my 84 250R is not runnin need help

[timberwolf78]

Well first off Im kinda new to the 3 wheeler world, been around them jus never owned one til now. I rebuilt the top end .040 over wiseco,stock reeds,and stock bottom end. I can get it to run but it will run good for a lil bit and can go wide open and sound good but then all of a sudden it just dies like you cut the fuel off,then you can pump the throttle bout 5 times wide open and kick it and it will run and then do it all over again. Its really starting to piss me off but I havent punched the tank or kicked it yet I jus walk away and try to think what in the hell could be the problem. The dealer has told me stuff but to me it seems like carb probs but other info would be more to my likeing. The dealer told me to check the crankcase bearings and seals that it could be sucking air but Im skeptical bout that . Please help if yall can it would be greatly appreciated.

[hrc200x]

Seems like carb problems are 80% or more of why trikes won't run or idle right. I think an air leek after the carb would make it idle really fast. Maybe check to make sure you have good flow going through the gas tank cap. Take the fuel line off the carb and see if the gas flows through the line and filter that should be inside the tank. The gas should come out very fast, not dribble. Now would also be a good time to see if your reserve and off on the petcock work.

What does the plug look like after it dies at full throttle? How is the spark? Is the air filter clean?

[DakotaDoc7]

It sounds like a shortage of fuel to me. See if the plug is wet, or if there is a decent amount of fuel in the cylinder. Other than that, maybe take the carb off and clean it up and see if anything is plugged.

[Dirtsquirt]

ok, definately a fuel problem.....


take off the tank and pull the petcock, Disassemble and clean the filter on that. pull the carb and clean that out good. use a high quality carb cleaner. Adjust the float level (I believe the stock carb should be 20mm). Reassemble.


if that doesn't lick the problem clean your air filter.

if even that doesn't do it, check out your reeds. they should lay flat against the cage and snap back when you bend them.

if the bike STILL has the problem try playing with the main jet
go down 1 or 2 sizes.


As always use a secondary fuel filter (cheap insurance, under $2.00) and if you just put the new piston in be sure to break it in properly....no full throttle running for atleast the 1st 3-4 hours...and NEVER start your bike up and go, always give it some warm up time. atleast 1 min.

[timberwolf78]

The reeds are in good shape,gonna check the filter and the petcock tomorrow, I just put the reed cage and the carb back on today because I thought it might be sucking air there so i made new gaskets, but it didnt help. The piston and rings are seated now. Do yall think that a pinhole in the float could also cause this.

[atc330r]

there is a brass screw at the bottom. side of float blow. its a fuel drain. run the motor till it dies. then open the drain. if there no fuel running out. the bowl is empty. you,ve checked everything the others have mentioned. did you make sure the float needle is clear? have you done a pressure check it,s the only way you can find air leaks. air cooled motors are real bad about that. you will need to use a sealer on, cylinder base, reed cage. maybe the head. pumping the throttle is not doing anything at all. there is no accelrater pump on those carbs. so whats happening is while your pumping the float bowl is filling with fuel via garvity. is the motor reving up by it,s self? the crank seals will cause this also. get a hold of the flywheel and jerk it up and down very fast and as hard as you can. if you feel any clucking at all. it can be bearings or a worn crank ( the end where the bearing is ). if the carb has the stock jets in it and you are not hooking up the stock air box. you will have to rejet the carb. be VERY CAREFUL with this motor they are unforgiving. let so know if that piston last you more than a week. you want to run about 2 tanks of fuel before you open it up. did you drill lude holes in the piston?

[timberwolf78]

atc 330r
Im fairly new to two stroke engines ,being that this one is the first that ive built im use to small block chevys.i can build them all day long but this little rice burner is starting to piss me off.ok to the question no it does not idle up on its own it has a dead spot when you gas it like its flooding out but its not,after it dies and i eventually get it restarted it will run for a sec then die, im hoping it aint the crank bearings and seals being that i dont want to sink any more money in this thing how would i go about pressure testing what you were talking bout

[timberwolf78]

duh you talking bout compression test

[atc330r]

even if the crank bearings/seals wee bad it would still run. to do a pressure check. you have to put 4/6 lbs of pressure in the crank case/cylinder and have it stay at that pressure for aroung 6/9 minutes. you can buy these set ups or make one. we made ours. you can get a rubber plug that fits the ex flang.then at the carb boot ( manifold ) remove the carb. heres what we did. a peice of pipe that fits in the the manifold. weld the end shut or?. tap a hole anywhere you want, now you need fittings, a pressure gauge that shows low pressure.and a air nozzle so you can use a hand tire pump. put all that together. i,ve also seen the same thing made out of pvc pipe. i looked easier. that was all glued together. i,am sure you could just go to home depot and get everything. the same thing is used to test pipe in a new home for leaks. any way with the pressure in the motor. spray soapy water ( simple green ) on all the joints, look for the bubbles. any place you see them will suck air when running. when it dies have a screw driver in your hand and open the drain, see if the bowl is dry. run 110 gas in that motor at around 28/32:1 you dont want to use unleaded in that motor. you gota be running out of fuel. even if the reedsare bad it will still run, crapy but run

[timberwolf78]

110 octane gas you gotta be kiddin its jus bored .040 with a cobra pipe thats all no head portin dont wanta race it jus ride it i mean i aint gonna be puttin around on it or nothin but i dont wanna have to be wide open all the time
right now its on 93 octane 50/1 factory specs and the honda dealer races them and he recommended that and to run the suzuki pre mix i know suzuki but that what he recommeded

[atc330r]

the factory specs on a air cooled 250r is 32:1 no matter what oil you run. the 110 is not for preformance its because its leaded fuel or if you can find lead in other octanes. that motor is going to run very hot. the 110 leaded will help to make in run much cooler. example: i have a sand dragster with a 356 porshce, no cooling system. if i run pump gas the ex will turn red hot in 15 sec,s on 110 leaded it never gets hot. in fact the ex pipe is painted and it will not burn the paint. i have 2 84 250r,s and went through a lot of headaches with fuel,pistons.problem sloved ( good gas, no forged pistons ). there a web site that real good on 2 cycle stuff. McDizzy.com i think thats how it goes. if not iam sure sombody will correct that, but check it out. they talk about the pressure testing. its the only why to besure your not leaking. a air leak will kill that motor real fast.

[timberwolf78]

if i run it and check the screw when it dies and fuel comes out then what

[timberwolf78]

also there is a giant sticker on the gas tank that says to mix the gas 50:1 and the mcdizzy.com doesnt come up

[atc330r]

pull the plug and see if its wet. i dont think it will be. you said after it sets awhile it will restart. most of the time when the plug gets wet she not going to start ( flooded with oil and gas ).

[timberwolf78]

the plug is always a lil moist but it doesnt have to sit but long enough for me to open the throttle a few times and kick it over 2 maybe 3 times and it fires right back up and it will go through it all over again

[atc330r]

both my 84,s have 32;1 and the 85 water cooled says 32;1. we run the a/cs at 28/30:1 amd the h2o at 40:1 on 110. i,ll check out McDizzy is got to be capital m & d made its .net or .org? god now gotta go look at the factory book to see what the ratio is in there. i wonder if that sticker is one that sombody put on it. it,s not a big one made 1 1/2" by !" white lettering

[timberwolf78]

no its a factory decal and man i appreiciate all your trying to help me with

[atc330r]

ok will it idle for any lenght of time? do you have an air cleaner hooked up?

[timberwolf78]

yes and no at the moment the air cleaner box and filter is off but it was doing the same thing with it on actually a lil worse with it on

[timberwolf78]

McDizzy.com .org . net none of them work

[atc330r]

ok i just went a checked my save file. its MacDizzy i think . com. what i have it his old site. some one referred to him last week and i linked to that ,came up with a newer version of what i have saved. much better. well it,s 1:30 here got hit it. i,ve got to put an 84 motor together in the morning. the air cleaner is a restriction. it works kind of like a choke. so with out it or if you put on a k 7 n filter you will have to go up on the main jet. with a fresh bore on it you will also need to go up on the main. it,s possible at a hi rpm your running out because the main jet is not supplying enough fuel, if itsjust doing it at a hi rpm. jetting is a real big thing with these. we run a mikuni 38 mm and with the last wiesco had a 430 main. just by switching to a art case piston. i dropped the main to a 380. the bad part is you need about 20 jets to do all this. go to a damn dealer they want 5 buck and a fair bike shop 2/3 bucks

[250sx]

man I don't care what that sticker says, you better stick with 32:1 at the worst. :eek:

[atc330r]

a man to that; the factory spec on any 2 cycle motor is for case piston. not forgd. he,ll be lucky to keep that wiesco going any way, but a 50;1 i it give it a few hours

[timberwolf78]

what kind of oil mix do yall use

[Dirt Digger]

I run golden spectrum 45 to1. No problems:)

[Dirtsquirt]

I currently run MC-1 at a ratio of 50:1 in my 1984 aircooled ATC250r. It has a .040 over wiseco piston. I'm ported for top end, have a Bassani pipe/DG silencer, and a Keihin PE 34mm.

My bike is a beast compared to timberwolf's, and I have been running 93 octane and this chitty wiseco for hmm, the past two years with my must be "super lean" mixture of 50:1. The previous owner ran this ratio since the early 90's. NO PROBLEMS

Ask Kasey, when I rode with him I didn't baby it and it hasn't given me one problem since blowing up the ART piston about 3 months after I got it.


Running 110 race gas is extremely unneeded in this case, and even if he needed it I wouldn't run that crap. AV is the way to go (and only about 1/2 the price)


-Dirtsquirt

(ohh, and Honda recommended 20:1 as thier ratio for the 1984 ATC250r....all they had back then was bean oil)

[timberwolf78]

my 84 also has a keihin carb no idea what size

[atc330r]

av gas has so much oxugen in it i cant run it in this motor. plus it,s 50 miles to get it the wrong way. 76 race fuel is only 3.65 a gal= the oil ( 927 ) comes out to about 6.50 a gal. what octane do you think av gas is? the # 1 deal here is to get leaded fuel no matter who makes it @ what ever ratio your plug will stay dry at. if you can keep a wiesco working for you great, but find me a 75 mm wiesco. like mr atc told us he can get a 300 piston from honda.( i cant, i deal with a honda dealer ? ) ask him for the part # no reply. that was 1 1/2 mons ago????? the bad thing about a case piston is it will come apart. where the wiesco wont.i like wiesco, but for us they dont last pro x doesn,t have them bugrat no deal. there are some venolia,s around. i,am now on our last rocky.

[timberwolf78]

the damn thing is gonna make me go postal,i ran it until it died and puled the plug on the carb no fuel came out .also with the filter off when i bumped it wide open there was a big mist of fuel that came out the back of the carb on the filter side i was wondering if this is normal or is that part of my problem

[timberwolf78]

i fell like a total dumass but what can i say im new to the wheeler worl but not really jus screwed up when it comes to 2 strokes i said the sticker recommended 50:1 but at closer look it said 20:1 would this make a difference in what the prob is with this thinf please help

[timberwolf78]

well i went and bought some more oil and 2 gallons of 110 octane leaded racing fuel ,mixed it bout 25/1 put the air filter back on and it helped a lil bit but still doing the same s#!t please help

[atc330r]

you,ve already cleaned out the tank,fuel supply line and the carb. go back the the carb and take out the float needle seat check behind the seat. there may crap stuck in there. if the neddle has a rubber tip it could be swollen and sticking shut. carbs seem to have a habit of sticking when they have been work on. when you put it back on. tap on the side of it. the fuel coming out of the back of the carb is called fogging. that will always be there. it should be a wrost a heavy mist. if it gets to a point of spitting, say almost like a spray of water then the reeds are not sealing. mix your oil in the range of 28:1 / 32:1. when you ride always carry 2 spare spark plugs and a wrench. good luck, dont give up. it just needs that old TLC. that thing will go like hell when you get the bugs out

[timberwolf78]

i have a dumb question but maybe it will solve my probs. what is the little brass elbow that comes out of the crankcase right beneath the carb it has a hose on it and use to have and extention that was plugged up is it a vent and does it need to be plugged off

[Dirtsquirt]

crankcase vent. (means your ATC is a US model) should not be plugged up.

[timberwolf78]

its not plugged up now cause i unplugged it when i first got it and it didnt run then because of a hole in the piston and now its still not runnin cause i dont know what the hell is wrong with it
:fire: :fire: :fire: :fire: im getting ready too :fire: the damn thing]

[Dirt Digger]

Replace your fuel line. It may be damaged on the inside. I have seen one act as though it had a check valve inside from a slither of rubber.:cool:

[timberwolf78]

the fuelline is fine ijus got my clymer manual inthe mail today. so today i changed the height on the main jet needle it was in the top slot so i put it down in the middle oneor 3rd from top it helped a lil but still runs for a sec then dies,also i jus ran it once since i changed this and when it died and i went to kick it back off on the second kick it back fired out the silencer (sounded like a 22 going off)no as loud as a shot gun but definately somethign is wrong , i left it alone after that cause my foot is starting to wana kick the crap outta the tank :mad: :mad: :mad: :bash: :bash: :bash: :mad: :mad:

[timberwolf78]

ha sanyone got any ideas what the hell is wrong with this thing , some thnik carb some think air leaks hell im open to suggestions

[timberwolf78]

also to me it only dies when it warms up i mean if i leave alone for a day and come back to it it will run for bout 2 min before it dies then after that when you finally do get it running again it only runs for bout 30 sec to a min so if that helps to find the prob please reply

[kyle]

just cheching,you ARE turning the choke off when it runs for two minutes and warms up right
kyle

[timberwolf78]

yes cut the choke of way before it dies

[timberwolf78]

if the float level was set to low would it run like this also to me it acts like the bowl is filling up then it runs all the fuel out of it and then dies , when i hold it open for a sec or two then the fuel fills the bowl again and then it will fire back up