86 250R carb/airbox questions

[dovesprings250R]

Sorry if this has been answered here before but I have the following questions

1. If I run a 39 mm Kehien carb on my 86 250R what exactly do I need to do to make it fit? I currently have the stock reed intake and stock airbox.

2. If I eliminate the airbox and go to a K&N type set up would that be better and or easier and what would be the downside to doing so? I don't ride in wet conditions if that matters.

3. With the 39 carb will my mileage decrease noticably?

4. Is there a different carb I should consider?

Thanks everyone.

[Black Sheep]

Sorry if this has been answered here before but I have the following questions

1. If I run a 39 mm Kehien carb on my 86 250R what exactly do I need to do to make it fit? I currently have the stock reed intake and stock airbox.

2. If I eliminate the airbox and go to a K&N type set up would that be better and or easier and what would be the downside to doing so? I don't ride in wet conditions if that matters.

3. With the 39 carb will my mileage decrease noticably?

4. Is there a different carb I should consider?

Thanks everyone.


Dove, the carb should fit in the stock intake with a little force. the best way to do it is buy a late model CR 250 intake. they are the same bolt pattern but to boot is designed for the 39mm carb the cr comes with.

i would not eliminate the air box. you need the still air it creates for better intake. without the airbox your filter is surounded by turbulant air giving inconsistant air intake. i would however remove the lid. If you want the best setup do what i did to copy team hondas air box. remove the airbox and pull the boot off that connects to the frame. remove the air boot that goes to the carb. cover hole up with a piece of plastic and rivit it to the air box. then buy a trx 250R air boot and install it were the frame to airbox boot was. only this time hook it up to your carb. this gives your air a straight shot to the carb. you will also need to use the TRX 250r air filter. this is not a simple bolt on you will have to take some time and do some small triming.

whenever you go to a bigger carb you will lose milage. its simple bigger carb needs more gas.

it depends on what your looking for. i ran a 39mmPWK on my R and loved it. you will lose a little off the bottom but there is a good gain on top.

[Dammit!]

For the airbox to carb boot, you'll need an empty Corona bottle and a heat gun. Add some grease and put the bottle into the boot (the end that connects to the carb), heat it up, let it cool to ambient temperature, then stick it in the fridge, then back to ambient, then heat it again. Repeat that about three times and it will remember the shape. Once it's all done it's still a lot easier to connect the tube to the carb with the airbox removed.

By the way, Rad valves have interchangeable adapters for different size carbs. If you're in the market for a new reed cage. I love mine.

I'm running a 38mm pwk for reference.

[Black Sheep]

By the way, Rad valves have interchangeable adapters for different size carbs. If you're in the market for a new reed cage. I love mine.




and if you are i have one for sale. its for a 39mm

[dovesprings250R]

:thumbsup: Thanks guys. I've had good luck all this time with my stock carb bored out a bit but it's time for more top end. I figured with the turner Hi Rev pipe a bigger carb will be in order.

[NOS_350X]

Brent, Just get an air box eliminator, The conditions we ride in it will be much better Performance and cost affective. Have you bought your carb yet? The esr airbox eliminator is just some raidiator hose and an bent piece of pipe and filter. If you really want some top end power get a 41mm carb. The biggest thing with the airbox eliminator is the 250r Filter to carb set up ist stupid not very good.

[dovesprings250R]

I haven't bought a carb yet, still thinking/researching it.

[NOS_350X]

I got a 41.5mm pwk body, needs slide, needle, cap and spring. $50 for you. Check out Sudco.com when looking for carb parts. They are the carb experts and have EVERYTHING.

[firefirefire90]

Dove I wouldn't eliminate your airbox. You may end up running into mud and I don't think an open air filter would fair well in that situation.

[Dammit!]

I ran without an airbox for a while and didn't care for it. I think the airbox even with no lid gives you some protection from blowing dust. The filter was getting dirty to quick without the airbox.

[NOS_350X]

Dove I wouldn't eliminate your airbox. You may end up running into mud and I don't think an open air filter would fair well in that situation.


Thats why you get a watterproof outerwear. :D Amazing what those thing will protect you from.

[Black Sheep]

DO NOT remove the air box. removing the air box is not a good idea. you loose H.P. every factory has tried this and while it may work on a dyno in controlled environments in the real world the turbulant air is harder for the carb to draw in. with the lid removed but the box on you have more then enough intake area. the still air creates a consistant environment and the carb has a steady supply of air.

[firefirefire90]

I have one of those to..i'd just rather be safe than sorry :shrug:

[Breastman569]

i run without the air box and i have never had any problems with it!
http://i74.photobucket.com/albums/i279/breastman569/Three%20Wheelers/PICT0691.jpg

[Black Sheep]

i run without the air box and i have never had any problems with it!

no but you'd have more h.p. if you did run one

[wild200x]

i am curently running the Alien w/no air box. but i am still learning. by the sounds of it, i may want to concider putting it back on?! i have so much more power w/all i have doen, but i eliminated the air box at the same time as i added the v-force reads and the 39 mm pwk. also got the port job. i still have the stock pipe and wow, i cant wait for my new one. i am amazed at what can be doen to these great trikes! i bought a new intake manifold for the new carb. just told them what i was doing and they had the right one in stock. Dammit's idea on how to change the size of the other end is awesome! hey, send me a Corona!!!!

[X053]

I havent bought it yet but
After doing a little research. I'm leaning toward this carb.
http://cgi.ebay.com/ebaymotors/HONDA-TRX-ATC-250R-38mm-KEIHIN-PWK-CARBURETOR-CARB_W0QQcmdZViewItemQQ_trksidZp1638Q2em118QQcategoryZ43979QQihZ005QQitemZ150191868401QQrdZ1QQsspage nameZWD1V

[wild200x]

I havent bought it yet but
After doing a little research. I'm leaning toward this carb.
http://cgi.ebay.com/ebaymotors/HONDA-TRX-ATC-250R-38mm-KEIHIN-PWK-CARBURETOR-CARB_W0QQcmdZViewItemQQ_trksidZp1638Q2em118QQcategoryZ43979QQihZ005QQitemZ150191868401QQrdZ1QQsspage nameZWD1VDude, you would love that! "buy it now"!

[dovesprings250R]

I'm torn between that 38mm as carb and the 39 pwk.

[jadleybray]

no but you'd have more h.p. if you did run one

Where are you getting this info from?

[Mr. Sandman]

The loss of HP without an air box argument sounds like it has some validity, but, I also think that a lot depends on riding conditions and the setup of your motor. After all, the engineers at Honda didn't have a clue about a lot of the mods that are in place now that were unheard of 20+ years ago.

My setup; I'm currently running a 38mm Air Stryker with no air box and have no problems whatsoever and it sure doesn't seem to be missing any horses either! However, because of the exposed filter I used to run an Outerwears over my K & N and it was so restrictive that it would constantly miss at WOT because it couldn't get enough air while hill shooting.

[jadleybray]

I wouldn't rule it out completely, but without actually sitting on a dyno and making one change at a time for a true comparison, I don't buy it. JMO but I would suggest that a larger filter might do the trick.

[Black Sheep]

After all, the engineers at Honda didn't have a clue about a lot of the mods that are in place now that were unheard of 20+ years ago.


I'm not talking about one particular machine. be it motocross bike, street bike, cafe racer. all the factories have a one time or another tried running without them on all there race bikes/quads. trust me those guys who designed your bike are pretthy smart.

I wouldn't rule it out completely, but without actually sitting on a dyno and making one change at a time for a true comparison.

it would be an inacurate test because there is no turbulance on a machine sitting still in a controlled environment.





look at it this way. your motor is nothing more then a glorified air pump. your lungs are nothing more then a glorified air pump.


imagine your in a car on a hot day. the windows are closed all you have is the small vent. its gonna get pretty stuffy in there. that is your airbox with its lid on. now imagine sticking your head out the window at 60 mph. you can breath but its an effort. thats without a airbox. now imagine being in the car with the windows down. thats your airbox with the lid removed.

[3razors]

Black Sheep knows what he is talking about. The best intake setup for the 250R for maximum hp was the TRX250r intake boot/filter. If you see one you'll see why, it is huge in volume and has a strait shot for air induction/tapers for turbulence. Honda put alot of research and design in it. Another note if you are not going to not run the airbox, dont simply just stick the filter on the back of the carb. There is not enough dead air space "volume". And at least use a intake track tube like pvc pipe or the esr deal. Just because something works doesn't mean its the best.

2 stroke mods are the SAME as they were 20 years ago. Porting, head mods, big bore kits, ect.

[Mr. Sandman]

Black Sheep knows what he is talking about. The best intake setup for the 250R for maximum hp was the TRX250r intake boot/filter. If you see one you'll see why, it is huge in volume and has a strait shot for air induction/tapers for turbulence. Honda put alot of research and design in it. Another note if you are not going to not run the airbox, dont simply just stick the filter on the back of the carb. There is not enough dead air space "volume". And at least use a intake track tube like pvc pipe or the esr deal. Just because something works doesn't mean its the best.

2 stroke mods are the SAME as they were 20 years ago. Porting, head mods, big bore kits, ect.

My air box is a "highly modified" stocker :lmao: that has been totally cut away to the point that all that's left are the mounts for the frame and the mount for the filter. It still uses the stock filter location, intake tubes, etc.

Yes, the basic mods 20 years ago are the same as now, but, power valves are now used, porting and carburetors are better designed (CAD), there's a variety of heads and domes available now to modify squish bands more so than just milling a head did 20 years ago and fuels & oils are more technologically advanced as well..

Now, I'm not trying to argue with anyone or hijack Dove's thread, it's just my opinion.

[dovesprings250R]

After researching a bit more and taliking with the guys at Ct and Trinity I hace decided to go with a 39mmpwk carb with the stock airbox and the trx 250R mod that blacksheep mentioned. Ct actually got the most HP with that set up in their testing. On a side note................If trinity knows your motor is for a trike they won't work on it, or even give you much help. That's a shame causr they're right by me.

[Dammit!]

Anybody got pics of the TRX airbox mod? This is the first I'm hearing about that.

[Black Sheep]

Yes, the basic mods 20 years ago are the same as now, but, power valves are now used, porting and carburetors are better designed (CAD), there's a variety of heads and domes available now to modify squish bands more so than just milling a head did 20 years ago and fuels & oils are more technologically advanced as well..


21 years ago the CR250R came with power valves. the 39mm PWK carb you buy today is the same one i bought 20 years ago. my motor was ported and the dome was rshaped 20 yrs ago but the head was never milled. basically what i'm saying is my 20 year old mods are still current. a port map is a port map and CAD has nothing to do with it. Cad just does the work for you instead of doing it by hand and CAD cannot port a motor. to this day a current CR 250 cylinder can bolt on a 21yr old ATC 250R. the best pre mix is still maxima 927. the same stuff i used 20 years ago.


Ct actually got the most HP with that set up in their testing


CT has been doing 250R's since the 80's. they are one of the best to choose from.

trinity wasn't around (or big) back then. i would not sweat them not working on your trike. your better off with CT. They built a sick ATC back then that was 40lbs lighter and STILL set up for MX. Trinity is more of a banshee specialist shop.



Anybody got pics of the TRX airbox mod? This is the first I'm hearing about that.

:nono: :nono: :nono: shame on you. you should do your homework:yup: :yup: :yup: I posted this tip years ago in the Tech forum:doh: :doh: :doh: ...:chuckle: :chuckle: :chuckle:

[Black Sheep]

hope this helps. while i got the idea from team Honda I came up with this on my own. Back in the day i saw a pic that dirt wheels snuck of marty harts 250r. he had a piece of plastic over his original air box hole on the side. it wasn't untill i saw my friends trx 250r that i figured out a way to mimick how Honda did. what Honda actually used i don't know

[Dammit!]

Not sure I'm getting exactly how it's done yet.

Cover up the airbox to carb outlet on stock airbox. Check.

Remove frame to airbox snorkel from stock setup. Check.

Purchase a TRX airbox to carb boot. Check.

Attach TRX boot to the hole where the frame to airbox piece was? Doesn't look like it would line up. Where do you attach the air filter and what kind of filter do you need?

[3razors]

Here is a setup I have seen alot of people run on both 3 and 4 wheel model 250rs.

http://web.archive.org/web/20050206040309/www.macdizzy.com/parts.htm

[Black Sheep]

Attach TRX boot to the hole where the frame to airbox piece was? Doesn't look like it would line up. Where do you attach the air filter and what kind of filter do you need?

my bad i'm sorry...us the mount from the trx (you'll need a trx air box) or fab your own like i did. I took aluminum coil stock cut it for length and width ( i don't remeber sizes) rolled it up and placed it inside the hole. then sealed it with silicone. the filter on one end and the boot on the other holds everything in place. then use a trx air filter. you'll also have to trim the opening in your 250R air box

[jenndnn3]

ill have to get picts of mine...

interesting feedback and read here...

Currently I use the macdizzy setup... Few exceptions are I use stuff from your local auto store...I used a reducer and hosing from the auto parts store, wasnt cheap but cheaper then buying it from trinity or Ct or whoever the hell sold it..I just copied it.. (Ill see if I can find the websight later) I kept the overall length from carb to air-filter My airbox is indeed gone... I dont ride My R in winter but if I did Blacksheeps mod would be the way I would go... Though It is easy to get the reducer and hosing from auto store..

I did get a gain in dumping my airbox... So this is a tough call..I definatly can see the points presented here.

Though the number one thing I love the most is the ease of getting to my Carb!! 2 mins its out no fighting....

How much HP loss/gain are we talkin about here anyway?

[Black Sheep]

this is what i mean. i exagerated the width for pic purposes. once rolled place it in the opening. then you can silicone it in place. the air filter and airboot help hold it in place. if you want to go farther with this design like i did purchase two hinsen air boot rings for the TRX and use them on either side. then have one taclk welded to the sleeve. and again seal it with silicone

[Black Sheep]

How much HP loss/gain are we talkin about here anyway?

you can lose as much as 5hp by removing the airbox. but on average probably closer to 2 or 3. depends on a lot of variables. a stock motor will lose about 4/5 while a heavily modified motor will lose a differant amout yet not be noticed because of all the other mods. while not huge numbers, in competition or the desire for max hp its a big differance for such a little thing.

the average trail rider may or may not know the differance. if you never use all your power then you won't know what your missing. it depends on how your ride your motor. if you are always over reving your motor past its peak spot in the powerband you won't notice it much because your wasting rpms anway.

for example it may be a differant trike but i remember when i first got mx 350x boy would it rev. i though it was insane. then i read the manual...peak power at around 7500 rpms ( i was screaming it past 10,000) bought a tach and re learned how to ride...and the differance in power was amazing.

so learning to ride in the "sweet spot" as it's called will help you learn a lot about your motor and the gains you acheive with each mod.

[jenndnn3]

I think you nailed it right there Blacksheep....

I actually was not going to say anything in this thread cause mine is kinda different to begin with.. It isnt your basic port and polish, carb pipe and so on mods..

But I do every mod systematically testing each mods as I went...(and am still going on)

I can tell it wasnt the airbox that brought about the most change, it was the pipe and especially the carb so far... I think even Ted can votch the carb difference and that not even being "dialed" in perfectly as he rode mine with the carb jump/change. (36 to 39)

I myself am average so I am not looking for the nats ass sorta speak, just the noticeable difference with ease... I do though have fun pulling what I can from each tinker I do...Failed or not..

[dovesprings250R]

Sounds like getting a trx airbox is the easiest. Less fabing it looks like. I'll let you all know how it goes.
Thanks Blacksheep.

[NOS_350X]

you can lose as much as 5hp by removing the airbox. but on average probably closer to 2 or 3. depends on a lot of variables. a stock motor will lose about 4/5 while a heavily modified motor will lose a differant amout yet not be noticed because of all the other mods. while not huge numbers, in competition or the desire for max hp its a big differance for such a little thing.




Where are you getting Those hp numbers from?

[Black Sheep]

your not going to get an accurate h.p number unless you can hook up a dyno while riding at 60+mph. if you notice i said ABOUT but there is a noticable differance. enough that can be felt by the right rider. there are two many other variables.

[jadleybray]

couldn't you say the same thing about your "seat of the pants" hp #'s?

[NOS_350X]

Well, when i take off the stock airbox and put on an esr aribox eliminator i gain, 5-10 hp. I can tell because im a highly tuned rider that rides every other day.

Seriously, TO ME, when i do go from a stock airbox, to an airbox eliminator I gain hp, Now im not going to throw out numbers because 5 hp is a TON of power on these little engines. It defently feels faster, NOW MRATC, the TRX filter to carb intake, is the best one, It has a nice taper to it. Im still going to say no airbox is best. The engine is sucking in, so if air is there its going to go in, where with an airbox the air just isnt there to be sucked in, the box is blocking it.

[jenndnn3]

Esr that was the name I was looking for thank you... Man that has been buggin me all day...

[NOS_350X]

Esr that was the name I was looking for thank you... Man that has been buggin me all day...

Yes lol, like you said earlyer the ESR airbox eliminator can be made with basic raidiator hose and some pipe. Im not a HUGE fan of it but it works and works way better than stock. KISS, Keep It Simple Stupid <---words i live by.

[MR ATC]

Well, when i take off the stock airbox and put on an esr aribox eliminator i gain, 5-10 hp. I can tell because im a highly tuned rider that rides every other day.

Seriously, TO ME, when i do go from a stock airbox, to an airbox eliminator I gain hp, Now im not going to throw out numbers because 5 hp is a TON of power on these little engines. It defently feels faster, NOW MRATC, the TRX filter to carb intake, is the best one, It has a nice taper to it. Im still going to say no airbox is best. The engine is sucking in, so if air is there its going to go in, where with an airbox the air just isnt there to be sucked in, the box is blocking it.



NOS, i seriously think you disagree with me just to start an argument. and in your blindness your hurt yourself. I remember ESR back when he went up against TEAM HONDA and they smoked him.

Listen we can go back and forth about this forever but your to thick headed to see any other way then some backyard hack way of doing things. obviously your smarter then EVERY FACTORY TEAM THAT RACES THE EXACT SAME MOTOR WE'VE BEEN TALKING ABOUT FOR 20+ YEARS. YOUR SMATER THEN ALL THOSE HIGHLY EDUCATED ENGINEERS THAT DESIGNED YOU MACHINE. YOUR SMARTER THEN THE WIND TUNNEL TESTING EQUIPMENT THEY EMPLOY. THATS RIGHT EINSTEIN DID YOU KNOW YOUR 250R's and 350X FRONT FENDER WERE ARYODYNAMICALLY DESIGNED FOR MAXIMUM AIR FLOW.

I DON"T KNOW ANYOTHER WAY TO PUT THIS BUT RE READ THIS AGAIN...



"imagine your in a car on a hot day. the windows are closed all you have is the small vent. its gonna get pretty stuffy in there. that is your airbox with its lid on. now imagine sticking your head out the window at 60 mph. you can breath but its an effort. thats without a airbox. now imagine being in the car with the windows down. thats your airbox with the lid removed."



NOW GO STICK YOUR HEAD OUT A WINDOW AT 60MPH AND TELL ME YOU CANBREATHE JUST AS EASY AS IN A ROOM OF STILL AIR.

THERE IS YOU K>I>S.S>

[NOS_350X]

Ya but the air filter isnt sitting out on the side of the bike, its under a seat, behind finders, engine carb shock all that stuff, your not going to get crazy airflow like your saying directly over the filter.


Now this may be completely rong but didnt TEAM HONDA have Pual Turner building there engines? Basicaly thats the same thing as Eddie Sanders. Now i know current day race teams, Team Honda, Suzuki, Kawi, Yamaha, can have anyone they want to build there engine, The Team recomends a builder but its up to the rider to go to whoever they want. For example Kawi recomends bubba stewert goes to Pro circut but He has an engine being built at Dasa currently.

I actualy worked for as a mechainc for a factory suzuki Rider for a few months. (suzuki recomeds they go to P2R)

When you told me you sent me the pm i told you i would respond with what i thought, i just waited. You had to know it would eventualy be comming. Im just trying to put out my best knoledeg out there, as are you.

[Black Sheep]

couldn't you say the same thing about your "seat of the pants" hp #'s?

ther not really seat of the pants. its a combination of things that give you an estimated result since it is impossible to bring a dyno on a ride.

I remmber years ago when i read a tech artical on this. a fan was used in a dyno room to simulate riding. under certain conditions up to 5hp could be lost.

not only are you exposing your filter to uncontrolled air flow but thier is also the possibility of heat from the exhaust warming the air that gets to your carb. the airbox acts as a shield and stores a consistent amount of fresh air.

i remember back in 96 when i was racing a CR125. the trick then was to cut open the slots just a little larger in the airbox. (something team honda learned and applied to the 97 model) however they also learned if the holes were TOO big it had a negative effect in the amount of 2hp. now on a 125 2hp is a lot. and that was just a small differance in size not a complete removal.

but no i can not say for certain the amount is exactly 5hp.

but 3 things i can say for certain

1. i will always trust the manufacturer who not only designed the thing but has been the most succesfull off road racing team in history and is known for its attentionto the tiniest of tiny improvements.

2. NOS will disagree with anything i say

3. common sense. still air is easier to breath then gail force winds!!!

[NOS_350X]

2. NOS will disagree with anything i say

3. common sense. still air is easier to breath then gail force winds!!!

I agreed that the 250r intake is a good route to go.

I dissagree that there are gail force winds under the seat, behind the finders, and behind the enigne

When running no airbox my whole filter gets dirty, that would tell me that the whole filter is being used to suck air. When using an airbox just the top does, that tells me that only the top of the filter is sucking in the dust ass air i ride in.

[Black Sheep]

I agreed that the 250r intake is a good route to go.

I dissagree that there are gail force winds under the seat, behind the finders, and behind the enigne

When running no airbox my whole filter gets dirty, that would tell me that the whole filter is being used to suck air. When using an airbox just the top does, that tells me that only the top of the filter is sucking in the dust ass air i ride in.


did you ever think about those two fat tires spinning wildly right next to the filter might have anything to add to the equasion(sp)

when i go riding in the mud the outside of my airbox is covered in it. Not because it "SUCKED" it in like you say but because my tires covered it. if my tires throw mud they also throw air. thank you your own argument proved my case to you.


as far as your other post i can't speculate as to what exactly the teams do with all there riders all the time. i do know this, no team runs without a airbox

[NOS_350X]

Dirt and dust dont quite move like mud, Try and thow a piece of paper, then wadd it up and throw it. Ever looked at the pro flattrack quads, and bikes, havent seen any airboxes in them.

IF the tires are thowing air twards the air filter then what is it?? Wind from you doing 50 mph or your tires?? because the tires are behind the aifilter, soo you gota pick, where is the gail force winds comming from? And since the tires are puting that much air right there by the filter why dont we use that as some sort of force induction. LOL Put your bike on a stand and put it in gear and get it wide open, The tires are moving that much air. Yes some but not enough to make a noticeable diffrence.

[Black Sheep]

IF you don't think that the combination of wind from riding and the air coming off the tires create turbulance then there is no explaining physics to you. this is not my rule, this is not team hondas rule nor is it flat track rules. this is a rule of the universe.

and still air is easier to breath. unlless its some kind of forced air induction which is totaly irelevnt in this discussion.


Team Honda Ran air boxes on OHHH What there 250R's which is the machine were talking about.


i can't explain COMMON SENSE you either have it or you don't


I' m DONE this tread had run its cousre. The author has made his decision based on his own research and this thread. Its job is done.


Good luck dove.

[jenndnn3]

Actually I think you 2 have a pretty decent discussion going...
If you could leave out the slight insulting and sarcasm both bring some legit arguments to the table. I can certianly read around em.. But really it aint half bad guys...

[3razors]

All factory teams whether mx or ATV still run airboxes on there machines. To me it seems that removing the airbox doesn't do much but get the filter more dirty. The engine can only breath a certain amount air in.

[Black Sheep]

Actually I think you 2 have a pretty decent discussion going...
If you could leave out the slight insulting and sarcasm both bring some legit arguments to the table. I can certianly read around em.. But really it aint half bad guys...

Jenn i'm always open for a good discusion but he's not arguing with me. he is arguing with what i call LAWS of the UNIVERSE. Still air is easier to breath in then moving air . Mankind can try all he wants but those laws do not change.


3razors also brings up a good point. most of these inacurate dyno test are done with clean air filters which will increase h.p. numbers but when they get dirty, which they will get worse without a box, then those controlled environment test are irelevent.

[NOS_350X]

Your directly relateing the speed your going with the amount of turblance you will get over the filter area. Im saying its guraded by everything, the components of the bike. So the high winds your talking abuot arnt there, so now your sayign turbulance. Well your not going to get 60mph tirbunial winds. Like i said if the filter was sticing out of the side of the quad maby but its tucked under the seat, guarded by many things of these winds. And physics, ok, winds cant go through thing.

3razrs, mx racing have to run them, there taking the chance of running in mudy or rainy conditions. Thats why im refering to flattrack. Thats a fair weather riding, and drag racers, every drag racer ive seen has never had an airbox.

[3razors]

I like topics like this. I see points on both, but a naturally aspirated engine will only draw a certain amount of airflow for the given size of the engine, if the airbox is the right size for the motor it doesn't make a difference if it was supposedly removed. That would only provide airspace that it doesnt use, and get the filter more dirty robbing hp.

[Black Sheep]

Your directly relateing the speed your going with the amount of turblance you will get over the filter area. Im saying its guraded by everything, the components of the bike. So the high winds your talking abuot arnt there, so now your sayign turbulance. Well your not going to get 60mph tirbunial winds. Like i said if the filter was sticing out of the side of the quad maby but its tucked under the seat, guarded by many things of these winds. And physics, ok, winds cant go through thing.

3razrs, mx racing have to run them, there taking the chance of running in mudy or rainy conditions. Thats why im refering to flattrack. Thats a fair weather riding, and drag racers, every drag racer ive seen has never had an airbox.

wow were geting waaay off base here arn't we. we went from a deserts 3wheel 250R in off road conditions and somehow flat track bikes and now quads are geting into the pic. not to mention you taking my "gail force winds" sarcasim waaay to literally.

Like i said if the filter was sticing out of the side of the quad maby but its tucked under the seat.

hmmm kinda kills your flat track bikes argument. since they usually stick out the side exposed to the air

mx racing have to run them, there taking the chance of running in mudy or rainy conditions. Thats why im refering to flattrack. Thats a fair weather riding, and drag racers, every drag racer ive seen has never had an airbox.


ever been to a indoor stadium SX race? ever raced inside a stadium.? can't get much fairer weather then that.


And physics, ok, winds cant go through thing. .


wind helped form the planet. again man (you nos) trying to be smarter then nature. if the "wind" can't get to your filter then were is it getting its air from...do you have a magic supply:lmao: :lmao: :lmao:


last but not least check out this photo of a 250R (original machine mentioned) in the desert (original environment mentioned) and the huge chocking dust cloud under and around the entire machine especially under the rear fenders. if the cloud of dirt is not enough to chock your exposed filter then look at it moving through the air...thier is your turbulance.

[NOS_350X]

You brought up hp and loss of it. Thats where i brought in the flattrack quads

I havnent seen any modern flattrack bike with a filter sticking out the side.

You said gail force winds, im just going off of what you say. Im not saying theres no wind over the filter you make it sound like theres a hurricane over the filter.

Lets just end this saying we dissagree, Neather is going to switch. The bikes i build will continue to have an airbox eliminator once i get to that point. Where yours wont.

[Black Sheep]

Im not saying theres no wind over the filter

ok now that you finally agree on that answer this


it is easier to breath still air vs turbulant air.

true or false.


no long speaches or examples from left field. just true or false.


Well your not going to get 60mph tirbunial winds.

if you are traveling at 60 mph then it stands to reason that the air around you is in motion. unless the laws of physics are differant were and how you ride. and since your airbox is removed then the filter is breathing in 60mph winds. that is unless you have some way to isolate the air that is in motion from around the air filter. hmmm like an airbox


Lets just end this saying we dissagree,

i tried ending this twice yet you kept pushing don't run away now.

[NOS_350X]

Ever have a cup in the bed of your truck? See it float around? now it wont fly out until it gets a nice gust to push it above the cab. Because its guarded by the cab, even with a flatbed or no bed ive see rags and such fly behind the cab and stay there.

I see where your comming from im just disagreeing that its going to take away hp. I feel that the way you see air moves and flows is distorted, and as do you about me. Lets just drop this, there will never be a winner. Move on to the next topic to b**** to each other about.

[Black Sheep]

Ever have a cup in the bed of your truck? See it float around? now it wont fly out until it gets a nice gust to push it above the cab. Because its guarded by the cab, even with a flatbed or no bed ive see rags and such fly behind the cab and stay there.

I see where your comming from im just disagreeing that its going to take away hp. I feel that the way you see air moves and flows is distorted, and as do you about me. Lets just drop this, there will never be a winner. Move on to the next topic to b**** to each other about.

thanks again, your truck anaology proves my point. the reason the cup can "float" is the amount of relativly dead air in the pickup that is provided by the bed and sides thus forming an "airbox". remove the bed altogether and see were the cup goes!!!


the only one who's thinking is distorted is you. your arguing against the laws of physics.


you still have not answered the one question i keep asking

is it easier to breath still or moving air.


For someone who acts so smart answer that simple question.

when you answer that then we can let it drop.

i told you i tried to drop this twice before, you did not , so don't back off now.

[X053]

What opinions can I get of this. :shrug:

http://i177.photobucket.com/albums/w236/X053/DSC01463.jpg

[firefirefire90]

I really don't understand it. I mean..does it replace the filter or no? If it does, that would be stupid because of the air coming through the frame. I guess it would just put more cleaner air. I would just think a filter cover over your filter and taking the lid off of the box would make just as much sense. That's just me though...

[Black Sheep]

that is a good set up. it provides more air then stock but also provides protection. This is a good mod for a rec/race machine or one with mild motor mods.


fire, it does not replace the filter. it alows more airflow like removing the lid but with some protection. just like thier are mild port jobs and full blown port jobs this is a mild air box mod.

[X053]

No, it does not replace the filter. Just a way to get more clean air into the airbox.
I was just wanting to see what people thought. Kind of on the same subject. :thumbsup:

[firefirefire90]

Would it work better than taking off the lid and just putting on an outerwear?

[X053]

It might keep filter cleaner longer. :shrug:
Would it work better than taking off the lid and just putting on an outerwear?This is how my 350X is!
Acutally no airbox at all. The only down side to running air box with no lid at all is that you can collect stuff in air box.

[Black Sheep]

Ever have a cup in the bed of your truck? See it float around? now it wont fly out until it gets a nice gust to push it above the cab. Because its guarded by the cab, even with a flatbed or no bed ive see rags and such fly behind the cab and stay there.

I feel that the way you see air moves and flows is distorted, and as do you about me.



here you go in your own words...

[Mr. Sandman]

21 years ago the CR250R came with power valves. the 39mm PWK carb you buy today is the same one i bought 20 years ago. my motor was ported and the dome was reshaped 20 yrs ago but the head was never milled. basically what I'm saying is my 20 year old mods are still current. a port map is a port map and CAD has nothing to do with it. Cad just does the work for you instead of doing it by hand and CAD cannot port a motor. to this day a current CR 250 cylinder can bolt on a 21yr old ATC 250R. the best pre mix is still maxima 927. the same stuff i used 20 years ago.

You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R. Sure, they were available but were they ever used on 3wheelers then like they are today? No.

Go ahead and bolt a current CR 250 cylinder and head onto your ATC. Will the power valves work just by bolting it on? No, so what's the advantage? Are power valved CR 250 cylinders used at all on ATC's? I've only seen one and it belongs to my brother and the adaption of it to his bottom end was not a quick and easy bolt on mod by any means.

Today's two stroke mods are basically the same now as they were then, I don't dispute that, but using CAD design for porting, carburetion, exhaust, etc. and being able to use a computer to test flow prior to building or grinding away has it's advantages to determine the best design. How well an engine builder follows that design and how good the performance will actually be is hard to say, but a computer program can take a lot of variables into play during design and hopefully the end result will be better performance.

Again, all of the above is just my humble opinion, which I believe I'm entitled to, just like you're entitled to have your opinion on everything you've posted in this thread (I don't agree with you on the Maxima 927 either).

[dovesprings250R]

Lots of good info on this thread. Thanks everyone. Not that they are the end all but I contacted CT racing regarding this issue since they are porting my spare cylinder. They said that in testing in various conditions that the trx airbox mod (or something similar) provided in their opinion the most overall power gain for a ported cylinder with a bigger carb. They cited turbulent air as the reason the no airbox set up provided less breathing. Jetting had to be adjusted to make up for less air.
They mentioned that very few tuners have really considered this as it is widely accepted that removing an airbox will provide better flow. A lot of the reason no airbox is popular with hill shooters is that the big 41mm carbs are hard to use with the stock airbox and for a short run the difference is very small. Their trx 250r's they raced in Baja had a trick airbox set up too providing better flow similar to the trx mod for the ATC. They used a Nacs blocker which I am not familiar with.
Anyway, for my specific use which is all condition desert riding I think the airbox mod is the way to go but Ct does say this will provide better breathing than a no airbox set up but is not as easy to do. (which is another reason no airbox is so popular) They also mentioned that in flat track riding and other shorter events the loss of weight might overide the better breathing making no airbox attractive to those riders.

[Black Sheep]

You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R. Sure, they were available but were they ever used on 3wheelers then like they are today? No.




then why would you even post this which is what i was responding too.


Yes, the basic mods 20 years ago are the same as now, but, power valves are now used,

what are power vaves used on that they were'nt used on 20 yrs ago. sorry my friend but the CR 250 is still the same basic motor it was in 1986. and the phantom non existing 87 r would not have a powervalve



Go ahead and bolt a current CR 250 cylinder and head onto your ATC. Will the power valves work just by bolting it on? No, so what's the advantage? Are power valved CR 250 cylinders used at all on ATC's? I've only seen one and it belongs to my brother and the adaption of it to his bottom end was not a quick and easy bolt on mod by any means.

you have a ESR kit. call up ESR they have a powervalve kit. Something Eddie learned from team HONDA back in 86 who ran CR cylinders on ther R's first without powervalves then later some with. part of the advantage was the chamber held more volume for the exhaust resulting in better low end. Again call ESR he will remember.

Today's two stroke mods are basically the same now as they were then, I don't dispute that, but using CAD design for porting, carburetion, exhaust, etc. and being able to use a computer to test flow prior to building or grinding away has it's advantages to determine the best design. How well an engine builder follows that design and how good the performance will actually be is hard to say, but a computer program can take a lot of variables into play during design and hopefully the end result will be better performance. .


what has CAD done for carburation??? the hot carb for a 250R is still a 39PWK same as it was back then. the porting will not change from 86 to now. what was most efficiant then still is today. What new pipe has come out from CAD??? CAD can only do what the person tells it to do. whether that person does it by hand or the computer does it its still up to the man running it. and he does what was done by hand before.


since this thread won't die and your entitled to your opinion i'm entitled to reply....:) :) :)

[3razors]

"You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R. Sure, they were available but were they ever used on 3wheelers then like they are today? No."

Well in 1986-87 Kawasaki had a 3 wheeler called KXT250 "Tecate" with KIPS powervalving, and in 1987 both the LT250 and LT500 were powervalved. I had a 1982 or 83 Yamaha YZ250 that was powervalved.

And I know for sure that Yamalube, Bel-Ray MC1, Golden Spectro were the same formulas that they are today. Just off hand I had a 1986 Dirtwheels with an ad with Maxima Super-M in it.

[jadleybray]

3razors also brings up a good point. most of these inacurate dyno test are done with clean air filters which will increase h.p. numbers but when they get dirty, which they will get worse without a box, then those controlled environment test are irelevent.[/QUOTE]

Few questions for everyone:
1- When did we start talking about dirty vs clean filters?

2- How can you run accurate comparison testing (any method for that matter) without a controlled environment?

3- And what testing would be used instead of the dyno for hp measurements like we are referring too?

[dovesprings250R]

3razors also brings up a good point. most of these inacurate dyno test are done with clean air filters which will increase h.p. numbers but when they get dirty, which they will get worse without a box, then those controlled environment test are irelevent.

Few questions for everyone:
1- When did we start talking about dirty vs clean filters?

2- How can you run accurate comparison testing (any method for that matter) without a controlled environment?

3- And what testing would be used instead of the dyno for hp measurements like we are referring too?[/QUOTE]

Good questions. As far as number 3 ct looks at the plug and are able to tell if a filter set up is breathing better or worse than another one. Not absolute science and hard to tell absolute power gain but enough to know that one set breathes better than another.

[3razors]

And what about K&N vs. Uni (dual stage foam)? :lmao: :chuckle:

Jeez I am way too bored and it is to late tonight...

[dovesprings250R]

And what about K&N vs. Uni (dual stage foam)? :lmao: :chuckle:

Jeez I am way too bored and it is to late tonight...

:lmao: Mee too. I didn't ask and don't think it would matter.

[jadleybray]

I know one thing for certain. I cannot fit a large enough filter inside a airbox for to get the amount of air that my motor needs!

Shoot it's still just a stock cylinder, lol, well started that way anyhow.

[NOS_350X]

How big is that stroker?? and do i see 2 spacerplates?? and a fuel pump so i would assume alochol. I bet that thing makes big hills small real quick.


Dyno runs for foam vs K&n
http://www.wppracing.com/ALL%20FILTERS.JPG700.jpg

http://www.wppracing.com/FILTER%20BEST.jpg



Good site with a ton of dyno runs

http://www.wppracing.com/links.htm

[Black Sheep]

K&N filters have always outporfomed foam filters in dyno rooms. However in the real world it is differant. Once a K&N filter gets a coat of dust on it it losse's a lot of ts flow. on the other end Foam filters when freshly oiled loose power vs. when they have a light coat of dust on them. I've seen many dyno runs to prove this as well. foam filters are designed to run slightly dirty. K&N are designed to run clean.

[Breastman569]

Black sheep you said something about sticking you head out the window at 60mph and trying to breath. well i tried it and breathing isnt the problem its exhaling and as far as im concerned the last time i checked engines dont ex hail through the intake.

also are you trying to say that the bike is going so fast the it is creating a vortex behind the bike making it so that there would be no air for the filter to breath?

and lastly im convinced that the air box was put there by honda so that you could ride through water.

[3razors]

There have been many independent test done about the filtering quality of K&N. In short they let too many fine dust particles in unless you use an outerwear (which does provide a decrease in airflow). Even K&N sell foam outersleaves for there filter and they need to be used in "extreme dust environments"

http://www.searchforparts.com/important_articles/k&n_vs_amsoil_air_filter.php

Again still every factory mx and atv team uses dual-stage foam because it protects the best while giving the most hp.

[jenndnn3]

I think the most reflective thing I am seeing here is for every mod there is definatly a trade-off. something gained something lost.

Nice engine Jadleybray hope to see it run at Rampage...

Extremely good discusion going on here...

[NOS_350X]

What 3 Razrs mentions i agree with, as black sheep did. A foam filter with no oil flows good, but there is no fliteration. A k&n flows better than a foam filter but lets dirt in the engeine. Here is how I pick.

Does every little half of a hp matter?
Is the cost of rebuilduing an issue?
Is the owner good at filter maintince?

For example my banshee has a k&n, I want as much hp as i can get out of it
My trx450 has a Uni/pro design foam filters. Rebuilds are expensive and the filters are cheap so we have 3 filters for the bike so theres always a clean one waiting to jump onto it. Yes its a race quads but the cost of rebuilding isnt worht the extra half a hp.

[3razors]

That is a good way to look at it....It all comes down to "Is the juice worth the squeeze"

[Black Sheep]

Black sheep you said something about sticking you head out the window at 60mph and trying to breath. well i tried it and breathing isnt the problem its exhaling and as far as im concerned the last time i checked engines dont ex hail through the intake. .

i did not say you couldn't breath i said it was more effort to breath moving air vs. still air. i used this as an example


also are you trying to say that the bike is going so fast the it is creating a vortex behind the bike making it so that there would be no air for the filter to breath?. no i'm not saying that. what i'm saying is without the airbox there is no "still" air for it ti breath.

and lastly im convinced that the air box was put there by honda so that you could ride through water.

unconvince yourself then. last time i checked supercross bikes don't run through water!!! last time i checked they all ran air boxes!

look your not just debating this with me your debating the factory race teams as well. factory race teams spend millions of dollars each year on the race efforts. don't you think if there were any benefits to runninig without one they would do it? they'll spend ungodly amounts of money just to save one pound. i'm sure if there was a benefit to removing a part for FREE even if to gain a 1/2hp they would.


if you still don't get it you never will.

[Black Sheep]

Well, when i take off the stock airbox and put on an esr aribox eliminator i gain,.



I just got off the phone with a guy at ESR (I won't say who) i asked him about this kit. he told me how it "allowed" the filter to breath more. I told him i read an artical about how the airbox was supposed to provide "stored" air for a consistant air supply. his response was no. the box was only for "mud and water" protection and was not needed. i then asked him why do the factories still use them on thier supercross bikes...there was a short silence then "uhhh uhhh" more silence then "do you know anybody with our kit so you could take a ride you'll feel the differance" i told him " no i do not. thats why i'm researching this. again i asked him "so you don't know why the factories still use airbox's" his response was "all i know is our kits allow them to breath more." he didn't give me any research numbers to back up his claime only that you could "feel" the differance.



i don't know about you ladies and gentalmen but the way i look at it, If he can't answer why the 5 most successfull off-road motorcycle race teams in history, the same ones who built the bikes, the same companie(s) that at one time hired him to race thier machines, the same companies who continue to win champinoships he's never won, why they still use airboxes if he can't answer that maybe just maybe he should think to ask "why do they?"


Dove, my congradulations on a Great thread topic. a lot of information was put out for all to read. issues were debated hard. it got heated at times but did not lose control (thanks jennn:thumbsup: ) and in the long run you did more research between this thread and calls you made then a man selling a kit.

[NOS_350X]

I Feel a diffrence, Dyno's feel a difference. Thats all im going to say about this. Esr has a dyno, They have a C&C, they have Fans, and they have fast bikes. IMO the no airbox is better. In yours it isnt. If everyone built engines exactly the same it would be boring. There has to be diffrences. This will be my last words on the subject

Stock ltr with no airbox with a 13hp gain.
http://sandsports.off-road.com/dunes/article/articleDetail.jsp?id=423507

Now another thing, Ive dynoed my banshee more than once and had other bikes on a dyno. Every time the dyno owner places 2 fans directly in front of the bike. To keep it cool and to simulate movement. I have never seen a dyno that they didnt do this with. On most the bikes ive built they start with airboxes, We remove them and it feels faster. Enough proof there??
Directly with me, On my banshee, about 6 months ago while working on it i dropped my airbox (YES MY SHEE HAS A AIRBOX) and cracked it between the filter and carb. With a race in 24 hours i had to Just clamp on 2 Uni filters (now theses where BIG MO-FO's) straight onto the carbs, I rejeted and had to go up 4 sizes on the mains, (from 165 to 175) and up 2 sizes on the pilots. During the race it was extremely hard to ride, I lost all my bottom end power, and it was all mid-top power. During the main i got it figured out and did extremely well, the bike was Much faster just harder to ride. I continue to run the airbox now on the shee, I would rather have the ease of riding than the extra power where it gave it to me. But if no airbox wasnt flowing better why did i have to jet up? Another thing is Every bike is diffrent, A bike with one type of reed cage or carb might work better with an eliminator or with a Box. Everything is diffrent on every bike or for each person, The best thing i can say is its $30 Give it a shot if you dont like it sell it on ebay and get your money back.

Im shure Black sheep you can make a bike fast, But it wont suit everyone. As can i, but its not going to satisfy everyone.

[Black Sheep]

This will be my last words on the subject


Now another thing,


which is it...your last word or not:lmao: :lmao: :lmao:

[3razors]

After reading the Suzuki article it states that all the mods total ie dasa pipe, power commander, filter setup, made 13 hp. It states just the filter mod is worth 3hp. I have a feeling if they did the dyno pull with the lid removed and K&N filter they would get about the same result.

[Black Sheep]

After reading the Suzuki article it states that all the mods total ie dasa pipe, power commander, filter setup, made 13 hp. It states just the filter mod is worth 3hp. I have a feeling if they did the dyno pull with the lid removed and K&N filter they would get about the same result.

i agree 100% just by removing the stock air filter and replaceing it will give you 1-2h.p. with the lid on. so this is not impressive. nor does it prove anything. if he were to do a test with his filter and airbox and then a test with his filter and no air box then it would have some merit here. but alas it is just another run of the mill dyno test comparison set up to get the results he wanted.

[jadleybray]

How do you "set up a dyno" to get the results you want?
I realize that one dyno to the next will read different, but a true tuner just uses the dyno for fair comparisons on products, setups and the like. The best thing you can do is try different combinations to see what works best for your motor.
Dyno numbers don't mean a thing, it's the base run then +or - from there that gives you feedback.

[Mr. Sandman]

then why would you even post this which is what i was responding too.

what are power vaves used on that they were'nt used on 20 yrs ago. sorry my friend but the CR 250 is still the same basic motor it was in 1986. and the phantom non existing 87 r would not have a powervalve

you have a ESR kit. call up ESR they have a powervalve kit. Something Eddie learned from team HONDA back in 86 who ran CR cylinders on ther R's first without powervalves then later some with. part of the advantage was the chamber held more volume for the exhaust resulting in better low end. Again call ESR he will remember.

what has CAD done for carburation??? the hot carb for a 250R is still a 39PWK same as it was back then. the porting will not change from 86 to now. what was most efficiant then still is today. What new pipe has come out from CAD??? CAD can only do what the person tells it to do. whether that person does it by hand or the computer does it its still up to the man running it. and he does what was done by hand before.


since this thread won't die and your entitled to your opinion i'm entitled to reply....:) :) :)

As pointed out by 3 Razors, other than the Tecate, production 3 wheelers never had power valves, even though CR's and other dirt bikes of that era did. Other than the Quadracers and possibly the Tecate 4, production quads never had power valves either. I may be wrong, but other than adapting a power valved dirt bike cylinder to a 3 wheeler back then, there were no other aftermarket options to go that route until the mid-90's or so like there are today. When did ESR's PV cylinder come out? and who ever said anything about an 87 R having a power valve?

As for CAD design of carbs, exhausts, porting etc. I guess I'm mixing things up a bit here as it's probably used more with the overall design of the above, but probably more so for today's new bikes, quads, etc. So calling the use of CAD a mod is incorrect.



"You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R. Sure, they were available but were they ever used on 3wheelers then like they are today? No."

Well in 1986-87 Kawasaki had a 3 wheeler called KXT250 "Tecate" with KIPS powervalving, and in 1987 both the LT250 and LT500 were powervalved. I had a 1982 or 83 Yamaha YZ250 that was powervalved.

And I know for sure that Yamalube, Bel-Ray MC1, Golden Spectro were the same formulas that they are today. Just off hand I had a 1986 Dirtwheels with an ad with Maxima Super-M in it.

You got me there! :doh: I forgot about the Kawi's but quads and dirt bikes don't count. I was mainly talking about Honda (production) 3 wheelers and power valves. As soon as I find that 87 though I'll let you know.

My reference to better oils is synthetics. Sure they were around back then but they've come a long way in the last 20 years. I totally agree with you on the other oils though. In fact, the Golden Spectro doesn't look like it has changed one bit since I use to use it in my old IT175 in the late 70's.

[Black Sheep]

How do you "set up a dyno" to get the results you want?



by setting the conditions to get the results you want. i'll use the artical as the example.

this company designed an air filter system based on this mans idea. he did this to make a profit. So right off the get go he has motive and is biased towords his filter.

the way to get his results were to take his filter and compare it to one filter (stock) in one sernario.

these are test and/or results he should have done/shown

1. stock filter in air stock box,
2. stock filter withour airbox.
3. his filter in air box,
4. his filter withour air box.
5. other filters in and out of airbox

any aftermarket filter breaths better then stock.

had he compared every filter in every senaro then it would be an acurate test.

I Feel a diffrence, Dyno's feel a difference. Thats all im going to say about this. Esr has a dyno, They have a C&C, they have Fans, and they have fast bikes. IMO the no airbox is better. In yours it isnt. If everyone built engines exactly the same it would be boring. There has to be diffrences. This will be my last words on the subject



Stock ltr with no airbox with a 13hp gain.
http://sandsports.off-road.com/dunes/article/articleDetail.jsp?id=423507

Now another thing,


Nick did you even READ the artical or are you so desperate to prove your point you mislead the results. He did NOT GET 13H.P. for removing the airbox. he added and exhaust system and did other mods..



..."Fuel ATV has developed a high quality intake system for the Suzuki LTR450 and coupled it with a Dasa exhaust system to add 13 extra horse power!"...


Additionaly his results are more atributed to his filter itself.


..."The increased intake velocity is due to a unique air filter design which has double the surface area than the stock filter. The air filter is unique because of a cone inside the filter to direct air into the carburetor rather than letting the air simply be sucked in. This means more air into the motor which translates into more"...



like i previously explained to jadleybray. had he compared his filter in and out of the box and did the same with the other filters then he could accuratly say or MORE YOU could say it was a result of airbox removal.

but then again he's an expert. he has a whopping 7 yrs experiance. Hell i only have 20+, Ct racing has like 40, Honda Yamaha kawasaki suzuki KTM they have like 60 70 yrs each. what do we all know.






and who ever said anything about an 87 R having a power valve?



You did!!!


You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R.

[Mr. Sandman]

Originally Posted by Mr. Sandman
and who ever said anything about an 87 R having a power valve?

You did!!!

Quote:
Originally Posted by Mr. Sandman
You show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R.

:wtf: Blacksheep, try again!

I said, show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R.

Now, how do you interpret that as me saying I'll show you an 87 250R with a power valve?

I have a feeling that you're so caught up in your argument with NOS350X that you're forgetting to breathe or can't because you've still got your head out the window at 60 mph.:D

[Black Sheep]

:wtf: Blacksheep, try again!

I said, show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R.

Now, how do you interpret that as me saying I'll show you an 87 250R with a power valve?

I have a feeling that you're so caught up in your argument with NOS350X that you're forgetting to breathe or can't because you've still got your head out the window at 60 mph.:D


try again at what???...you said it...your the one who mentioned it in the first place. i just responded by calling it the phantom. i never said you would show me one. you said...


"show me a 3 wheeler that was running a power valved motor 20+ years ago I'll show you an 87 250R."...

all i said was that even if the phantom 250R existed it WOULD NOT have one.


so in effect i was backing up your statement of 3 wheelers NOT having a powervalve...that is untill we BOTH forgot about the TECATE



i'm not arguing with him he's arguing with FACTS.

[jadleybray]

[QUOTE=Black Sheep]by setting the conditions to get the results you want. i'll use the artical as the example.

this company designed an air filter system based on this mans idea. he did this to make a profit. So right off the get go he has motive and is biased towords his filter.

the way to get his results were to take his filter and compare it to one filter (stock) in one sernario.

these are test and/or results he should have done/shown

1. stock filter in air stock box,
2. stock filter withour airbox.
3. his filter in air box,
4. his filter withour air box.
5. other filters in and out of airbox

any aftermarket filter breaths better then stock.

had he compared every filter in every senaro then it would be an acurate test.



So how does this show he setup the dyno to get the results he wanted. Apparently the test he did supported his idea, right. Don't you mean that he wasn't thorough with his testing? at least in your mind

[Black Sheep]

what i said was..."another run of the mill dyno test comparison set up to get the results he wanted...."

i did not say he set the dyno itself. i said he made the CONDITIONS of the test so it would support his idea.

he did not test every sernario so it is an inacurate test plain and simple.

any filter other then stock will show improvment so how does this prove it was the airbox...it doesn't

and if not doing a complete test...another words both filters with and without air box followed up by other filters with and without...is in your mind accurate. then there is no point continuing this conversation. Did he give resulte for the stock air filer without the box...no did he give us results with his filter inside stock airbox no.

then this guy has what 5-7 yrs experiance. boy call the factory teams tell em theve been wrong the last 30-40 years.

ANYBODY and I mean ANYBODY can take one idea and manipulate the end result to support there original idea. its ONLY when ALL facts are gathered that you have a true accurate test. To me the best way to test something is to try and DISPROVE your idea. that is unbiased.


this thread is a perfect example. one one end you have NOS who is sticking to his guns to support his idea. he is backing this up by his OWN test...of course he's not going to do test that would prove him wrong...why would he. his only defense is this..."


[QUOTE=NOS_350X] Stock ltr with no airbox with a 13hp gain.
http://sandsports.off-road.com/dunes....jsp?id=423507

did he mention in his thread that the 13hp. was the result of a filter AND PIPE.

NO! just..."Stock ltr with no airbox with a 13hp gain"

i've never seen a STOCK machine come stock with a hi performance aftermarket pipe.


on the other end you have my argument backed by CT racing one of the premier ATC race teams back in the day and still a major player in the ATV world. A team that has won severall championships plus 40+yrs of factory race teams. not to mention the majority of aftermarket hop up shops and satalite race teams. CHAMPIONSHIP AFTER CHAMPIONSHIPS. plus basic physics. and even NOS himself backed it up with his paper cup /pickup comparison.



so here is the score

Major championships won (profesional points championship)

NOS...0
ESR...0
Sandsports...0

blacksheep...0
HONDA...40+ (rough estimates)
Yamaha...20+
Kawasaki...20+
Suzuki...20+
KTM...20+
CTI...2 i know of
PRO CICUIT...15+
DG...5+



the proof is in the results

[NOS_350X]

Im done arguing the physics as to why no airbox breaths better. When i was the mechanic for the suzuki rider we count alter the frame, the bike must keep stock gemotery. This included pipe, intake, swingarm and such. AMP, Wants the bikes to appear as stock as possable, thus making it look like the bikes dont have a ton of money into it and that ricky charmacel is on the same or close to same RMZ450 that i can go pick up at the dealership. Now if they made it unlimited and we ended up with custom frames and crazy looking ****. Why do you think no racing has turbo's on the bikes, They wont let them, Rules limit what they are allowed to run. Come out in the dunes and watch the FAST bikes and count how many have ariboxes and and how many dont. From your math with the LTR, your saying JUST a pipe gave that bike a 18 hp increase, BECAUSE removeing the airbox takes away 5 hp AND THATS YOUR NUMBER!!! Air is everywhere, as long as the engine is getting it thats the importatn thing right?? If there was no air we wouldnt be able to ride, we would be sutck to little electric scooters, So lets just be glad where on earth. :) AND MARRY CHIRSTMAS BLACK SHEEP :)

[Troll]

DO NOT remove the air box. removing the air box is not a good idea. you loose H.P. every factory has tried this and while it may work on a dyno in controlled environments in the real world the turbulant air is harder for the carb to draw in. with the lid removed but the box on you have more then enough intake area. the still air creates a consistant environment and the carb has a steady supply of air.



I was amazed at the improvements with the lid mod's.........:thumbsup:

http://www.3wheeler.org/vb/attachment.php?attachmentid=9483&stc=1&d=1148182249


http://www.3wheeler.org/vb/showthread.php?t=24243

[Black Sheep]

When i was the mechanic for the suzuki rider we count alter the frame, the bike must keep stock gemotery. This included pipe, intake, swingarm and such.


oh that clears it up last time you said it was due to mud and water. now becaue of rules. thats a new one. only took 98 pages before that one came out! i wonder what you'll come up with next. hmmm could it be because they like to provide homes for mice when the bikes sit around!!!

pipe stock geometry huh. well have you ever built a custom pipe??? t0 get more H.P. you make it bigger (4 stroke) or change it shape (2 stroke) thus altering what class...

little jimmy raise's his hand..."oh oh oh i know MR ATC geometry!!"

intake? hmm you alter the opening in path of the intakes gasse's ( you know like V force reed cages Boysen reed cages, larger carbs.)thus altering what class???...

this time little suzie answers "I know that MR ATC that would be Geometry!!!"

Frames stock...huh? Ricky charmicle is like what 5' nothing. His subFrame is lowered 10mm (plus his seats are modified) thus altering what class???...

Little danny jumps right out of his seat "I know MR. ATC the frames geometry."

Thats right boys and girls so what do we have for our class??? well lets see

Jimmy gets an A+
Suzie gets an A+
Danny gets an A+
Nick (Nos) F



Why do you think no racing has turbo's on the bikes, They wont let them,


put down the video game. turbo are you kidding me???

seriously have you ever ridden a true Supercross track??? I have. the last thing you want aproching a 70' tripple is turbo.



Come out in the dunes and watch the FAST bikes and count how many have ariboxes and and how many dont.

Do you know why this is??? because I sure do!!! those bike are highly modified big bores and the STOCK air box is to SMALL so they remove it. IF however they built an airbox or used one sized for there motor then they WOULD see the diffence by running one.


but don't just listen to me...


After researching a bit more and taliking with the guys at Ct and Trinity I hace decided to go with a 39mmpwk carb with the stock airbox and the trx 250R mod that blacksheep mentioned. Ct actually got the most HP with that set up in their testing."


[QUOTE=dovesprings250R] I contacted CT racing regarding this issue since they are porting my spare cylinder. They said that in testing in various conditions that the trx airbox mod (or something similar) provided in their opinion the most overall power gain for a ported cylinder with a bigger carb. They cited turbulent air as the reason the no airbox set up provided less breathing. Jetting had to be adjusted to make up for less air.
They mentioned that very few tuners have really considered this as it is widely accepted that removing an airbox will provide better flow. A lot of the reason no airbox is popular with hill shooters is that the big 41mm carbs are hard to use with the stock airbox and for a short run the difference is very small. Their trx 250r's they raced in Baja had a trick airbox set up too providing better flow similar to the trx mod for the ATC. They used a Nacs blocker which I am not familiar with.
Anyway, for my specific use which is all condition desert riding I think the airbox mod is the way to go but Ct does say this will provide better breathing than a no airbox set up but is not as easy to do. (which is another reason no airbox is so popular) They also mentioned that in flat track riding and other shorter events the loss of weight might overide the better breathing making no airbox attractive to those riders.


well thats ends that argument you have. oh wait your more experianced then CT. after all you got a couple of months working at suzuki


From your math with the LTR, your saying JUST a pipe gave that bike a 18 hp increase, BECAUSE removeing the airbox takes away 5 hp AND THATS YOUR NUMBER!!! AND MARRY CHIRSTMAS BLACK SHEEP

ummm yes it is but i did say "UP to" and "ABOUT" depending on CONDITIONS


don't try and maipulate my words I know what i said. It's how you take it that's the problem your having!!!


HAPPY NEW YEAR NOS

[jadleybray]

somebody send me a airbox. I'll run the test

[NOS_350X]

ummm yes it is but i did say "UP to" and "ABOUT" depending on CONDITIONS


don't try and maipulate my words I know what i said. It's how you take it that's the problem your having!!!


HAPPY NEW YEAR NOS

Im just going off what you said, YOU said about 5 hp, Or up to 5 hp so thats what i went with, Based off of your highly tuned dynamoater you have built into your body.

If we all put bags over out heads what would happen?? thats what an airbox is doing to a filter.

Do your homework before you make **** up.


http://www.amaproracing.com/prorace/pdf/SX_MX%2007%20Rulebook.pdf

[jadleybray]

I am gettin the feeling that results would have to be team honda, suzuki, yami, for ya to accept the results though

[NOS_350X]

Ok everyone Mr atc and his engering degree is right Now everyone that has airbox eliminators take them off and put yoru box back on, hes right, im wrong. Open air filters cant suck in as good as guarded ones.

[Black Sheep]

Im just going off what you said, YOU said about 5 hp, Or up to 5 hp so thats what i went with, Based off of your highly tuned dynamoater you have built into your body.

Do your homework before you make **** up.


whoa space cowboy re read what i said before you make YOUR accusations

I remember years ago when i read a tech artical on this. a fan was used in a dyno room to simulate riding. under certain conditions up to 5hp could be lost.

or how about your words..

Seriously, TO ME, when i do go from a stock airbox, to an airbox eliminator I gain hp. It defently feels faster,


are your feelings more sensative then mine. im sorry did i hurt them!!!




not sure why you posted the rules i'm well aware of them but your still doing what you do best. skating around my questions like always.

in this entire thread i've answered rebuted your questions and post and stayed true to my position from 1-100. you've not answered 50% of my questions and keep brining in irelevent arguments and contridicting yourself.

[Black Sheep]

I am gettin the feeling that results would have to be team honda, suzuki, yami, for ya to accept the results though


now your just not making sense. your taking one thing i said and acting as if it's my only point.


if for some reason your think NOS is smarter then them they by all means listen to him.

but answer me this. CT racing is against it removing the airbox. when Dove called them they had explanations for both sernarios. However when i called ESR he could not give me an explanation he just skated the issue.


I do not go by race results only.
I do not go by seat of pants only
I do not go by 1 engine tuner only.
I do not go by my own opinion only.
I do not go by 1 dyno run only.
I do not go by a bunch of locals riding up a hill


what i do do is research the entire subject. factor in race results since racing has always inproved the breed. look at and listen to other tuners ESPECIALLY ones with MORE experiance then me. look at and study multipul dyno test and runs. I read research articals done by people not associated with the product being tested and have nothing to lose or gain by the outcome.





If we all put bags over out heads what would happen?? thats what an airbox is doing to a filter.


what size bag...lol would you like paper or plastic

thats about the strongest argument you've made this whole post. for the first time in this thread you made me think for a second. however if an airbox collapsed like a bag would when you breath in then this point would have some validity. but alas it won't and the bag will.

see with the bag as you breath the bag contracts thereby forcing the air supply to diminish. the airbox will always have the same shape therby the same air supply....ooops you proved my point again. not to mention you exhale into the bag. i've never seen a motor exhaul into its intake system

[NOS_350X]

are your feelings more sensative then mine. im sorry did i hurt them!!!
.

in this entire thread i've answered rebuted your questions and post and stayed true to my position from 1-100. you've not answered 50% of my questions and keep brining in irelevent arguments and contridicting yourself.


No not reay this thread actualy isnt bothring me one bit. I come on , check it, reply then go on with my every day life. Not like you, at least what your claiming in the pm's to "make me look stupid."

You say i skate around your questions what have "skated around"

You still hvent told my why i have to jet up when i removed the box on my banshee for the one race?? why answer that, YOU HAVENT,

Then i got thinkin. YOU said that the reason the guys here dont run them because, they cant fit a big enough filter in the box. WELL then thats my case, On every bike i build, the engiens are so built i cant fit a big enough filters in boxes.

[Black Sheep]

hmmm private messages hense the word "private" i mean yours are so flatering as well right??? to keep this out of the ight club hmm maybe thats why i pm'd you. maybe i was trying to motivate you??? see below.

i can't tell you why you have to jet up. maybe because you change everything???


[QUOTE=NOS_350XThen i got thinkin. YOU said that the reason the guys here dont run them because, they cant fit a big enough filter in the box. WELL then thats my case, On every bike i build, the engiens are so built i cant fit a big enough filters in boxes[/QUOTE]


Now thats what i'm talking about. THANK YOU!!! I'm glad this got you thinking. It took 100+ post but you finally got it.
That is The most inteligent thing i've read from you. You and I in our debate have taught our lesser mechanically inclined members something.

they now know that when running mildly modified motors with stock size air filters they should run an airbox. However if they are running highly modifed big bore motors they need a larger air filter and that larger air filter needs a larger air box OR it should be removed.

just like i said and you finally picked up on.


now i know you have mechanical skills, i know you like to tinker, i know you like to try differant ideas. so try this, build a larger airbox for one of your machines. keep it in proportion to the stock filter/box combination.

whats the worst that could happen?


K.I.S.S. right? larger motor needs larger filter needs larger air box. if you just modify the first two (engine, filter) without the last (airbox) then its not fair test to compare with or without the airbox. to do a true comparison you need to test a larger airbox.






p.s you never once answered if moving air is easier to breath then still
and if your exposed filter gets more dirt on it like you admited then doesn't a dirtier air filter breath less? hense negating any improvenment you might have gotten in a room?

[Red Rider]

Black Sheep & NOS,

I think we all agree that this debate over which is better, running an airbox/removing the airbox completely, has reached mythical proportions. That's why I've called in the experts. That's right, I called the MYTHBUSTERS, and they've agreed to do an episode on this very subject. Black Sheep, even you should be impressed & pleased with the Mythbusters scientific & thorough approach with their testing/fact finding to either prove or disprove this myth. Look for the episode this coming season on:

MYTHBUSTERS
8/7C on the Discovery channel. ;)

[NOS_350X]

Black Sheep & NOS,

I think we all agree that this debate over which is better, running an airbox/removing the airbox completely, has reached mythical proportions. That's why I've called in the experts. That's right, I called the MYTHBUSTERS, and they've agreed to do an episode on this very subject. Black Sheep, even you should be impressed & pleased with the Mythbusters scientific/thorough approach with their testing & fact finding to either prove/disprove this myth. Look for the episode this coming season on:

MYTHBUSTERS
8/7C on the Discovery channel. ;)


Im wondering if your serious, that would be awesome if you are.

[Black Sheep]

Black Sheep, even you should be impressed & pleased with the Mythbusters scientific & thorough approach with their testing/fact finding to either prove or disprove this myth.

thats what i based my pickup truck analogy on a myth busters episode. they tested whether or not a pickup got better milage with the tailgate up or down. when it was in the up position there was a pocket of air in the bed of the truck that let the oncoming air go over it. with the gate down it created turbulance and got less milage. hense the dead air that allows a cup to float around in the back. removing the bed would only increase the effects the gate did.

[3razors]

So when is this episode going to appear? I just learned that factory GP superbike teams run airbox's on their machines.