Big bore ATC 250r

[3 or die]

need links to big bore sellers. ATC 250r

I would like a Super high rev for a insane top speed

Figure sombody knows who I sould contact

[MR ATC]

big bore motors are not the way to go for hi revs. a bigger bore will reduce revs.

[3 or die]

if you had a 85 250r, and you wanted it to run 85mph plus what would you do as far as motor, gearing, and rear tires. I weigh 255lbs.Thanx

[deathman53]

I have a esr 330 on my atc its ported for low-mid and the gearing is low 14/38, it still rips and is insanely fast. doesn't rev fast, but if you have it ported for top end it will scream. but a big bore isn't the way to go for fast revs, a stock clyinder with a cr ignition, ported for top end will do what you want and alot cheaper. get 14/37 gearing, 15t won't fit, top end ported, 39mm carb, cr ignition and you will be unstoppable

[3 or die]

will you describe the cr ignition. I assume you mean a cr dirt bike ign. Size, and year, and any adaptors needed to instal thanx allot

[2strokepower]

I am running a 15/36 with 20 inch tires and have a ported cylinder. I like the topend but i will be putting a 14 tooth sproket on soon to get back a little lowend for mine.

[MR ATC]

Originally posted by 3 or die
if you had a 85 250r, and you wanted it to run 85mph plus what would you do as far as motor, gearing, and rear tires. I weigh 255lbs.Thanx

i have the motor ported for top end power, run a top end power pipe (paul turner) run a 39mm carb, rad valve, run a cr ignition ( ESR sells them with adaptor kits) the lighter flywheel will let it rev more and quicker. run 37 toothe rear sprocket and 22" light weight tires. do this and you'll be over 90mph

[3 or die]

85/86 250r high speed project

PORT STOCK CYLINDER FOR MID-TOP END
? 39MM CARB
TOP END PIPE( paul turner)
? LIGHT WEIGHT FLYWHEEL
CR IGNITION(ESR)
14 TOOTH FRONT SPROCKET
37 TOOTH REAR SPROCKET
22" LIGHT WEIGHT TIRES
? SWING ARM

I added swing arm to this. It will have to handel as good as possible, Do we need a longer swingarm?

please post link to dealer for paul turner pipe, esr for cr ignition, and for carb, need to know make, model, and a rough jet guess till it is fready for fine tuning. I am gonna do all this right here step by step, with pics and prices.

think I have found a complete 85 250r with low compression for this project.:)

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2476240397

[MR ATC]

i would not use a 14 tooth front sprocket on a 250. a 330 ok but not 250.

longer swingarms do not always mean good handling. they do provide more straight line stability but at the expense of turning capabilities and handling. unless it's a straight line dragger i would not go more then 2"

yes that is a good carb but, try to find out if it's the newer designed striker carb

[3 or die]

r u saying 13, 37.For sprokets
Who has light weight flywheel?
and still need link for esr, for cr ign

Thanx

[3 or die]

had to double check, but yep, my 84r has fresh 22x11x8 titans.

cost- ON HAND

PS somebody sell me some used tires to go back on 84 stock rims for it.

[3 or die]

I found site, but cant find a cr ignition

http://www.esr250.com/search.asp?CatalogName=&keyword=cr+

[deathman53]

I used to use a 14/39 combo on my ported cylinder, 38 a/s, v-force reeds, esr atc 5 pipe and it pulled no problem, I used 20" tires too. 14/38 was faster and would pull it, but I wanted more response for mx. i'm talking about that cr250 igniton, esr sells the adapter plate and complete system to mount to a trx/atc. on a trx its real easy to mount, but the atc requres some createtivity to mount the coil. Now I'm using a 14/38 on the 330, top out pretty fast, but I use it for mx, so top end isn't a concern.

[Rocketman]

ESR's web site itsn't real up to date, and doesn't list everything they have or do. Best bet is to call them.
They can also lighten your flywheel. Or if you want to buy a new one that is already lightened check out www.rickystator.com. they sell one.

[3 or die]

got with esr today, cr ignition is 489.00, comes with light weight flywheel, and all wireing needed, to include new stator.( has been orderd)

out of 39mm air stryker carb.


having controversy about 38mm vs 39mm lets hear some argument for each!CURRENT MONEY SPENT $510.74

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=35597&item=7900949848&sspagename=STRK%3AMEBWA%3AIT

[SpeedBump]

Originally posted by MR ATC


yes that is a good carb but, try to find out if it's the newer designed striker carb http://www.keihin-us.com/pwk.htm

They don't make a 39mm PWK AirStriker. They only make the quad vent AirStriker in a 35mm, 36mm and a 38mm. (people may modify them and call them 39Airstrikers, but Keihin makes just those 3) I can get just about ANY Keihin or Mikuni carb you would want. Me and my partner are authorized Sudco dist. As far as top end, you may be better off buying a smooth bore 40-41mm from some of the top engine builders. You will pay more, but.....speed costs $$$$$$, How fast ya wanna go? :headbang:

[3 or die]

for this trike my goal is 85 plus. I have a fatty pipe, the 400$ for a hi rev is hard for me to swallow. I may see what we get with it first.

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2476240397

CURRENT MONEY SPENT $695.74

[250sx]

damn, guess I better go ahead & get that 300 kit for the T3 rebuild. :demon:

[MR ATC]

Originally posted by SpeedBump
http://www.keihin-us.com/pwk.htm

They don't make a 39mm PWK AirStriker. They only make the quad vent AirStriker in a 35mm, 36mm and a 38mm. (people may modify them and call them 39Airstrikers, but Keihin makes just those 3) I can get just about ANY Keihin or Mikuni carb you would want. Me and my partner are authorized Sudco dist.

your partially correct. you can't get one through Sudco. BUT you can get one through HONDA. they came STOCK on certain CR 250's. HONDA which OWNS Keihin only sells certain carbs to distributers while keeping other models as HONDA only items (meaning you can only get them through HONDA). that is why you have to buy some jets from them and them only.

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=43972&item=2476108171&sspagename=STRK%3AMEBWN%3AIT

curent money spent $704.24

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2476108293&category=43972&sspagename=STRK%3AMEBWN%3AIT&rd=1

CURRENT MONEY SPENT $730.24

[Mr. Kasey]

dude if you get that head make sure you have it surfaced,,, it has been cleaned up with a wire brush and thats not a good idea on aluminum,,,, you can see how uneven they brushed it in the pictures,,,, also i would be very careful with used reeds if you are spending all that money why take a chance ,,,, look them over very carefully to make sure they are not delaminating or have and cracks,,,

are you going to have the head shaved and rechambered?
how is doing your motor work?

[3 or die]

thanx allot, this is why I am doing this in front of crowd, need some help...Bill

I want a topend machine, high rpms. I planed on port, and polish for that. Suggestions would be great. Got resurfasing, what else while it is there?

[MR ATC]

well so far your going in the right direction with your motor but, there are some other areas you can work on that will help. removing excess weight from the entire trike. but before you do that what type of riding are you going to do. I ask because some areas you don't want to lighten if your going to do serious jumping/off roading. but even if you are some areas like aluminum rear wheel hubs will help, also lighter wheels, lighter brake/locknut hub, lighter sprockets, swingarm, you see for every pound of rotating weight you take off it is = to 7lbs of dead weight to your motors performance. lowering the entire trike will help too.

[3 or die]

currently I plan on spending as close to 1000.00$ as possible on mods. This pretty much gets the motor headed in right direction. After we get that, and the speed is around 85(radar verified), then I will have thread moved, and we r gonna do a frame up, make it perty, restoration. Powder coat, plastic, shiny stuff. I think then we will upgrade to some lightweight aftermarket items.

This basicly is gonna be a straitline, dont get muddy, dragrace, drive once a month trike.

[dunerash]

Mr ATC Is right get rid of all the unnessarey weight.. If your just going to straight line it make it longer, lower and lighter.. Some other things you might want to do is get rid of the skid plates grind off the mounts, lose the airbox, the radiator overflow rezzi, alot of the mounts that hold the radiators in can be taken off.. Some people take off the front brakes and disc.. You can also turn the front end around(So the tire/rim is in front of the axle.. makes it longer)... I tried this...Didnt like it for duning :eek:

[3 or die]

here it is for those who have not seen one. You would think for $510.00 it would have come with a kill switch.

[3 or die]

Well, I didnt think my trike was actualy gonna sell, but its official now. So I found this one here after a few days of surfing. Folks we r now doing a full restoration. This is a 1985 Honda atc 250r. It has little compression, no throttle assembly, no headlight, and no front fender. We wont need a headlight with the cr ignition in use. $600.00

[3 or die]

current money spent $1330.24

[3 or die]

current money spent $1330.24

[3 or die]

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=35580&item=7901463577&sspagename=STRK%3AMEBWN%3AIT



CURRENT MONEY SPENT $1380.24

It dont look like I am gonna be able to keep this under $2000. Eventhough I got the trike cheep. If the bottom end, and trans is all ok, still need new tires, oem plastic, powder coating, and and bearings and seals. We will see.

[250sx]

Bill, when it's done I would like to turn this thread into a webpage of its own. I'm going to just leave it in here instead of the lounge or pic board since it will still be dealing with perf. upgrades. Is that R the one that was for sale over near memphis on ebay?

[3 or die]

No dan, I found this one in upstate PA. At the moment the prices are coming up on them. Its funny how they vary from month to month. I have known about this trike for a while, when I noticed how expensive the rollers have become I went ahead and got this. The air rs are starting to come back up also. I have noticed them around 750$ this week. Two weeks ago they were around 400$-500$.

[3 or die]

well after driving 22 hrs I got this thing home and had to pull the top end to see what its problem was.........ewwwww. Been a while since I saw one busted this bad. Rings are completely melted to it also. Hey guys need some tec help. there is an arrow on piston. Point it down then read

at top of piston is h58e9
center is 1 50mm
526p6
co

trying to figure out what the size is so I can get next size bigger and have cylinder bored. Suprizingly its not real bad, minor damage from debri.

[3 or die]

i figured it out. Mine is 50mm, gonna get a 75mm and send it to shop for work, will get all surfaces redone so it seals up good, anything else?

[jsformenow82]

have a question i just bought a 15 tooth for the front and im lookin for speed what rear sprocket size should i get for my 85 atc 250r stock is 13/39 should i stay with a 39 rear or go smaller for more speed

[deathman53]

I wouldn't use a 15t sprocket. For the very simple reason that you can't use a case saver. If you case saver mounts are already broke, then go head. If they aren't, go with a 14t sprocket, a 36 or smaller rear sprocket and keep/get a case saver. You can still use a case saver on a 14t, you may need to grind it somewhat bigger to work. I would much rather sacrifice some speed to know that if the chain breaks or de-rails, it won't break the case and cost alot more in the end. Is the 10mph worth a $2,000 motor rebuild? Also, make sure, if you do keep the 15t, that is full shouldered and as wide as the stock sprockets. Some of the aftermarket sprockets are narrow and require a 3 mm? spacer. Those sprockets tend to destroy the shaft or strip it. It doesn't have enough meat on the sprocket to firmly grap onto the shaft and strips the shaft and/or the sprocket. 1 tooth in front is equal to 3 in back. I use a 14/36 it has more top end than what is needed for open mx, 5th is hardly ever used and 6th is never used, I have 18" tires also. I use it because it smooths the power alot and isn't quite as "jumpy". I can't see, unless you are doing, desert riding, why w/ 20" tires and 14/36, you would need more speed. It would be close to 90 mph with that combo.

[YAMAHONDAMAN]

center is 1 50mm
526p6
co

trying to figure out what the size is so I can get next size bigger and have cylinder bored. Suprizingly its not real bad, minor damage from debri.

p6 is 60 over .. not much left .... 2mm over is the same as YZ and TRI-Z .. 68mm
What we do is install the YZ piston with the 1/8" spacer plate when it gits to .08 over.... if my memory is right ?

[Mr. Kasey]

holy digem up 5 year old threads!!! i thought 526 pistons go to .120 over... ??? thats why the long rod motors use a spacer to use the short rod piston when they go over 080.. am i wrong?

[YAMAHONDAMAN]

Yes they can go to .120 over.. you are correct Kasey
what we did was "copy" the Curtis Spark's Cyl's.. he used the Long Rod with the YZ Piston along with the 1/8" Plate.. that set up worked much better than just a over bored Honda
on the short rod motor's we would take off like .07 from the bottom of the cyl,, then trim the same off the bottom of the piston because it would hit the crank..no spacer plate.. :headbang:

[jenndnn3]

You can use a 70mm Aircooled piston with long rod 4 mil stroker,, no spacer...

[YAMAHONDAMAN]

Jenn .... Re-Sleeve Required ?

[jenndnn3]

no sir :lala:

:burnout:

But you will need to cut/modify the head.

[ron]

I don't want to pay 12.00 a quart for honda fork oil is there a different brand i can use.

[NOS_350X]

You can use ATF.