The ONGOING question!!! JETTING!!! NOOOOO

[ATCRYDER]

Welp--I boguht my bike pre-(re)jetted from my original owner...Im not saying he didnt due it great (he did) but his riding may have been differant from mine. On a 200x: I want to have the bestr possible top end with it. So: Im gonna ask you guys to help me out with jetting recomendations...ill also have to find my current settings asap. My *important*mods are as follows:

87 200X..stock carb (would buy a performance one...if i could get one--havnt found anythign yet)...also: carbs in the regular stock needle position...:

12:1 .020 over Wiseco
Kevlar Clutch Kit
K&N air filter
Mid range webcam
Cobra Full exhaust
Slighty polished exhasut port
14 tooth front, stock rear sprocket
Im running 20x10-9''s right now but will be running 22's soon.

Thank you ALL very much & im sure Ill be alot happier when I find out the best jetting to go with.

Rob

[Fuzzy]

The stock main for it should be a 108. Jetting isnt going to make as much difference as setting the carb up right for the motor. I would adjust the heck out of it. Try moving your clip on your needle down one notch at a time. And see if you can get it to get too much fuel. And start loading up. If you can then you dont need a bigger main. But if you want to try to pump some more fuel through it. Try a 110 or 112. You can buy jets 1 at a time from dennis kirk. And they are only 3-4 bucks each. So maybe order a few different sizes and keep playing around with it until you cant get it to burn all the fuel anymore. Then back down to the next smaller jet and adjust it from there.

Let me know what you come up with. I am kind of curious of just how big of a jet a 200x can take. Maybe a 115 or so. Just remember when trying a bigger jet to drop your needle down so that it dosnt get to much fuel at startup and flood out.

[markb]

i was up to a 116 main and a 45 pilot before i decided i was asking too much from a small carb. i couldn't believe how much that thing wanted a bigger carb. you can try the bigger jet the only problem is without changing needles you'll have holes in the powerband. and trying to do plug chops with race gas is useless since it wont color the plug.
mark

[Fuzzy]

Mark what did you go back to then a 115?. Or did you go down even more?. I run a 110 main in mine and it runs great. But i was thinkin of going maybe to a 112. At what jet size did you start to notice the needle becoming a problem?.

[markb]

i'll try to anwer this and make sense if i get lost please ask more.
it wasn't a specific jet size per say, going to a 116 was really a band aid for the needle. i really ran into a problem when i changed the cam for 2 reasons.
1: a cam change usually moves the peak power devloped to a different part of the power band ie more mid or top end which changes the fuel requirement in that area but doesn't alter the low end fuel needs that much. now if the only thing you change is the main jet say to a larger size so the top end power of the cam is realized the low end suddenly becomes sluggish because it's rich. this is where you would need to change the needle to one with a fatter lower section which lets less fuel thru the main jet at part throttle but tailor the needle to have the same top step diameter to allow the main to flow enough top end fuel. this is the problem i have with the 30mm on mine now, if i put a main in it thats big enough to give me good low end the wide open throttle falls on it's face because it's too rich. i really need to buy some more #5 mic needles.
#2 i didn't realize how under carbed i was, it was like trying to flow a gallon thru a drinking straw. when i put the 30 on i actually gained bottom end which isn't typical with a larger carb.

i'm not familiar with your motor or elevation but we had 112's in ours with 12:1 k&n and suppertraps and i thought they were jetted pretty crisp but i'm at sea level. when i put a 110 in my stock 200x with the cheap supertrapp it didn't like it at all and became sluggish. the thing is most people will never ride a properly jetted bike because it's alot of time to do it right and the brass isn't cheap when you get down to it but if you've ever been on one its an incredible experience, that 200 will rev like a 2 stroke. i'll tell ya that mine aren't always jetted spot on because i'm too lazy once i get something to work to mess with it.......unless somebody starts beating me. i guess you can try it because worst case is your out $4.
mark:lala:

[86waterpumper]

I too have serious issues with my jetting. I also have a 200x an 85 model. This motor was rebuilt not too long ago, it refuses to run lean enough. It carbons up the plug and blows soot over everything, but it always cranks in two kicks or so, and it will sit and idle, I ran it 100 miles at the sand ride the other weekend, but I'd like for it to run better than it does. I had to turn the idle screw wide open because it loads up so bad. Now the bike is on it's first or second bore, it's got a crappy cobra pipe, I took the airbox lid off which helped it some but it still isn't enough. I have tried everything just about, I've set the valve lash, I've checked the iginition timing, I've torn the carb down and totally rebuilt it, put a 108 main jet in and stock needle with the clip in the middle position which is already one notch leaner than stock. Should I just keep moving the clip on the needle leaner? I just can't understand why the bike can't be jetted at least like a stock bike when it should need to be a tad bit richer than stock w/o the airlid box and the pipe I would think.

[Fuzzy]

Thanks Markb that made great sence.

And 86waterpumper. When you say you had to turn your idle screw wide open. Do you mean your idel speed screw?. Or your idel mixture screw on the bottom of the carb?.

Also what type of
gas do you run?. I only run preium 92/93 octain. And have you tried other spark plugs?. Different brands or heat ranges.

As far as running stock jetting. That only works if the engine is set back to completely stock specs. And is still running stock intake and exhaust. Once the engine has been touched or things have been changed. Throw the stock jetting book right out the window. You will need to find the setup that works best for your motor.

When i set up a carb the first thing i do
is adjust idel mixture. Then idel speed. And then i adjust the needle to find what position i get the best midrange and top end from. Dont worrie about what notch it is on. Just read your plugs and see what they are telling you and how the machine proforms. And if you still cant lean it out. You might want to go through the carb and clean it out and check to see what condition your needle and seat are in. And also check your float level. It might just be flowing too much gas into the carb.

[86waterpumper]

thanks for the help fuzzy, well the airbox is still stock, it's got a unifilter on it, as far as the carb goes, I went over everything pretty good a few weeks ago when I had it apart, and put a new needle and seat all jets a whole rebuild kit in it. The float didn't appear to be off, everyone I've seen that is that far off leaks gas out the bottom of the carb and mine doesn't even if the lever is left to on. I have a little better luck running a hotter plug than stock, I am running the 7es plug ngk instead of the 8. I have set the air mixture screw to stock specs, I turned it all the way closed and then backed it off 1 1/3 turns or whatever the manual specified. The idle screw on the side is the one that I have to idle up all the way or the motor loads up at idle and dies. I guess I just can't understand why the motor isn't flowing enough air to need at least stock jettting, I don't think the needle is going to lean it out enough but I am going to try it tommorow and see. I'd like to get it fixed, because the bike runs excellant otherwise, and I know I'm carboning up all the motor innards hehe. I will have to get it alot better before any reading of the plug is possible, because it's always solid sooted up black. I know the bike is solid compression wise, it has new valves, the plug is never wet with oil, and the smoke is always just solid black, not blue or white. I am wondering if the silencer is partially plugged up or something. Would it hurt the bike or just the neighbors to run w/ the silencer off? :D

[86waterpumper]

oh forgot to add I run 93 octane exclusively in it.

[ATCRYDER]

Octane level isnt gonna make a differance in the way the jetting works...

I run 94 octane with the proper octane booster levle mixed in...but ive also ran standard 87 pump gas.

Rob

[250sx]

Dude, just buy you a couple of smaller jets and give it a shot. It may not be what you're supposed to run, but if it works then quityerbichin'. :D

[ATCRYDER]

ahaint*****, beetch

[Fuzzy]

Originally posted by ATCRYDER
Octane level isnt gonna make a differance in the way the jetting works...

I run 94 octane with the proper octane booster levle mixed in...but ive also ran standard 87 pump gas.

Rob

:ugh: WHAT!!!:ugh:
Octane makes a world of difference in the jetting. The higher the octane the easier it burns and the cleaner it burns. So the more fuel you can throw at it. If you run low octane crummy pump gas. And it has trouble burning it. You have to jet down to keep from fouling plugs. And it can also lead to hard starting problems when running a bigger jet.

Thats been my exsperience anyways.

[ATCRYDER]

>>><<><><>Dan--thanks for changin my name :headbang: ><<>><

Fuzz: sorry but I totally disagree frome xperience. Ive ran 87 in both winter & summer @ differnat times, and Ive run race gas in both seasons as well. Absolutely no differance to my jetting, or having it foul, or even starting easier (it starts on 1-2 kicks 87 octane or even 94).

Rob

[markb]

sorry some times i'm on the board all the time , you did the right thing.
time to start eliminating things
1 did you own the bike before thr rebuild? if you did was it running decent?
2 when you had the carb apart did you remove the pilot jet and blow the passage out, it's lower and next to the main
3 is the plug "wet black" or "dry black" when you take it out
4 when i adjust the valves i set them like this
when exhaust starts to move adj. the intake valve
when the intake just closes adjust the exhaust
this puts you in the base circle of each lobe it's kinda tough in these motors cause the stator want's to move the crank on ya but you can do it and it's very accurate this way. i set my roller cams this way because of the lobe shape and timing. try it out
5 after you put it back together did you loosen the timing chain adj. dolt to tighten the chain?
6 after that long ride did you notice if crankcase oil level was down?
rob do you have a digital camera so we can see a picture of the piston when the "death rattle" gets too loud and you have to pull it. high compression requires hi octane the only way around it is a large supply of pistons. i ran mixed 110 and 94 in mine and the pin froze to the piston from metal flaking caused by detonation. this is why i have to split the cases this winter to put a new rod in because the small end is oval now. i'm not saying this to start a pissing match it's just that less experienced people should know the other side before they make an expensive mistake.
mark
mark

[jenndnn3]

Ok I got several questions about this Octane level thing....Well more of statements. Yeah none of my buisness but here goes. I can understand where your coming from Rob and why you dont see a difference "Yet". When you play swap around you are gonna burn up some of the garbage from the lower Octanes. I have a test for you to run so you can see the difference. Since us newer 200x are able to pull the heads without pulling engine this is an easy enough test for ya. (except for me I have yet to find that stupid adjusting bolt) Run it 2 months with lower octane pull and look. Then run it with higher octanes pull and look. Also Havnt you said that you put additives in your fuel? A very apparant way is to find a older car. Listen to the car with 100000 miles when you put the 2 different fuels in it. You will hear a distinct rattle from a lower octane level, especially hill climbing (where you really need your gas to burn quickly and cleanly). if you get that in a car imagine what it is doing to your bike.

[ATCRYDER]

Jenn: I can tell you this:

Higher Octane -does- run cleaner to a point of preferance where you wouldnt want to bother going back. I dont plan on running pump gas again with my 12:1 ratio.

What i do is:

Mix high octane gas (94) with the adequete amount of octane booster & then some fuel/engine cleaner and thats my fuel source.

Rob

[markb]

jenn i would have never found the damage to my 200 by removing the head. my 200 damage was the same as the 396 in my chevelle, the pins are fitted at .0002-.0005 and the "mild" detonation picks up microscopic pieces of the pin bore in the piston and deposits them on the pin. over time the pin will bind in the piston and since the 200 or my 396 doesn't have a needle bearing in the rod it's gonna make the small end oval.
your newer bikes might have a chamber design that resists detonation much better than the older bikes i don't know.
the kind of detonation that would show by removing the head would be severe and very loud. the top of the piston would look like you took an ice pick to it. robs cam could be helping him also if it's big enough it would lower the cranking pressure at low rpm's enough to eliminate the detonation.
86 water pumper where did you go?
mark

[don250R]

okay guys...............
one more time......
the best place i have found about carburetor tuning is by Canadian Dave.
the numbers in the article deal with kdx's, but that doesn't mateer. The theory is still the same.
What works for one bike, won't work for another.
he explains plug-chopping, mixtures, etc.
every bike is different................
and on the octane issue........
any mechanic knows that with increased octane, you retard the timimg even more.
If you don't, ur wasting ur money.
not just an opinion, personal experience.

[250sx]

don't you mean advance the timing?

[ATCRYDER]

Retard the timing? That wouldnt be very nice. :chuckle: :chuckle:

[86waterpumper]

sorry markb didn't check the posts for a couple days. To answer your questions, yes I did take the pilot jet out and blow it out, clean it etc, and I had the bike before the rebuild, but not really enough to tell how rich it was running I maybe ran it around a few minutes in the yard. I will try your method and reset my valves again it can't hurt. The carb when I took it apart had a 80 main jet installed in it, which makes me wonder if someone had the carb bored way out or something. However it still ran too rich with the 80 main too. They had some weird fat needle in it so I put back the stock stuff it didn't seem to make a huge diff although it did run a bit leaner than before. I didn't loosen the chain tensioner up, this may be part of my problem, the bolt that holds the chain tensioner in the motor can be turned by hand, and never seems to tigten up, I guess I've been afraid to loosen up the chain tensioner and have it fall down in the motor or something. But if the timing is off it is definately not varying back and forth, the bike runs pretty consistent even though it's too rich.

[Mr. Richard]

hey 86 wp that might be a mikuni jet in a kehien carb the #'S aren't the same,,, or a kehien jet in a mikuni,,,,, you know what i mean,,,,,, so that could be why its real rich,,,,,,,,,

[86waterpumper]

hmmmm you mean the 80 that it had? That is a possibility I guess. I can't look at jets and tell any difference with the naked eye anyway. I don't believe that the jet in there now is a mikuni, simply because my rebuild kit came with two, and they were numbered 108 and 110, I believe the 83 200x got a 110? and the 84/85 received a 108 in stock form. At any rate I'll lean the clip off some more, and try that on for size.

[markb]

86 wp the thing we're really interested in at this point is if the plug is wet black(oil) or dry black (mixture). the main reason i mentioned the valves is so we have a baseline to start from since tn is a long way from ct.
are you sure it's a 200x carb? i saw one on a 78 kawasaki 250 street bike that would bolt on.
your right about canadian dave's article it's really good but the point of hi octane is so you can optimize timing without detonation, retarding it would be counter productive.
mark

[86waterpumper]

the plug on my x every time I've looked at it had a very sooty dry appearance...I've never known it to be wet at all...and it certainly looks like the 200x style carb. Looks very similar as well to my buddie's carb that is on his 200s...

[markb]

if it was my bike i would borrow a carb like your friends 200s unit and see if that clears it up. i can't see it being rich from jetting unless somebody really screwed with that carb.
if the carb doesn't fix the problem i would fix the tensioner, i don't know the duration of the 200 cam but under running tension with a really loose chain you might have the exhaust valve slightly open when the piston starts down again drawing in some exhaust charge.:confused:
mark

[86waterpumper]

yeah that's what i want to do is bolt his carb up and see how it runs with it on there. It is a smaller carb by a couple mm, and has smaller jet so if it runs rich with it on there I know something is def wrong elsewhere. I've got to get this jetting thing down, my klx650 is running lean, haha I need a whole book dedicated to jetting