im ready to pull my hair out!!!!!!!!!!!

well i give up, first off my bike lost all compression, and wouldnt run without choke, so i tore it all down and checked the valves 2 of them seemed gummed up so i pushed on them a lil to free them up, so i put it all back together the right way timing was all right on, i must of did somethign right cuz then i had compression back but still the same thing it would only run with choke on or if i gave it any gas it would just kill, so i figured carb might be plugged i cleaned all the jets out and then put it back on same thing again started 2nd kick but only ran with choke, on , so i figured maybe those 2 valves r still a little gummed up so i figure ill teaar it all apart again and take the head to a local shop to see if they cant get them to free, up well i tore it all down and now the valves move freely they arent stuck or nothing, u push right down on em and they pop right back up unlike before, so now i have no idea what to do ive tore it down twice and carb is clean, so i figure im gonna just take it to a shop this week and just let them figure out this problem, have any of u taken your bikes to a shop yet and what have u had to pay around total, times like this i wish i still had my 2 stroke, by the way its a 2002 250f only about a month and a half old, and im really getting frustrated with it fast. if any of u have any suggestions let me know, sorry its so long, i have alot going through my head, and am not looking forward to a bill that is gonna be huge after they r done with it , thanks alot

what i would do is actually rmove your valves, springs, and retainers, then if possible, soak them in a carb cleaning acid bath. if you cant do that, get some "casite grease out" and clean the valves really really well. Also check your valve guides, and if necessary, clean them. Also what about your jetting? are you jetted too rich? You may also want to check your electrical connections, namely your TPS. If it is loose and not properly working, it can do weird things. once my tps was dissconnected and i dindt know about it, and the bike would stall randomly while riding. hope this helps.


maybe I am missing something, Di you not say

I freed the sticky valves and all is ok.

If the bike is not running in outside of choke, have you looked at any of the electrics ?

Originally posted by Vanilla Gorilla:

Also what about your jetting? are you jetted too rich?

this really doesn't make sense if the bike runs okay with the choke. That would indicate that without the choke a lean condition exists. I'm not really implying that this is the answer, but it's just a thought.

whats tps?

Throttle position sensor TPS :)

Have you tried draining/cleaning the carb and filling with fresh gas? Sounds like carb problems to me.

i am so fed up with this bike, its brand new and in peices, i have gone through everything carb, i checked the needle the clip didnt fall off, and i made sure all the tps hook ups were togehter nothing came unplugged, the valves were gummed up so i cleaned them and i got them to free up, i never checked the vavle clearance cuz it starts first kick still and i dont think they should be out of whack this early since it ran one day flawless then the next day all of this, it starts up first kick up, only runs with choke on and if i give it any gas or turn the choke off it will die, looks like im off to the local shop to get screwed over :) thanks alot YAMAHA for a brand new bike that wont even run, this will be my 2nd race i have to miss now, if i had my 2 stroke i may have to spend 70.00 but it would be fixed the first day. does any 1 have any more suggestions, i love this biek when it runs and im not having these probs but right now it might be seeing a for sale sign very soon, i have done everything right maintenance wise, i dont understand it and help will be greatful

Well, if you now have compression and it idles with the choke on, then the valves are opening/closing, it's getting air, it has ignition, and it's getting fuel from the choke circuit. With choke off it dies, so the only change is loss of fuel source. I would almost positively say it was a carb problem(pilot circuit...could be a piece of trash stuck in there), but could be electrical I guess. Either way, if the valves are functioning with the choke on they won't quit working when you give it gas, so that should be ok. I'm betting the shop fix won't be bad if it's just carb cleaning/adjustments, or faulty electronics that I'm sure Yamaha will correct if it's that new...they always took care of me. Good luck, I don't think it will be that bad.

[ June 10, 2002: Message edited by: mxaddict ]

I don't know if you get oxygenated gas up there in Minn. but if you do, it can wreak havoc with that bike.

As for the loss of compression, make sure that you decomp lever has slack in it.

Also, make sure your float bowl is adjusted to within spec.

[ June 11, 2002: Message edited by: Hokie ]

[ June 11, 2002: Message edited by: Hokie ]

If he had enough oil in the filter to gum up the intake valves, I can almost gaurantee the pilot circuit is plugged.


Take the carb off and soak it in carb cleaner, I mean soak it. Let it sit for an hour or so in the carb cleaner.I use McKays. It comes in a gallon can with a little dipping basket. And if you have a safe way to warm the carb cleaner, like leaving the can in the sun or something do that too. Put the motor back together. Its not the problem. And make sure your hotstart knob is fuctioning correctly too. If the hotstart knob isnt seated properly, it will give you an identical problem.

If you have been trying to clean the carb with that spritzer style carb cleaner, your basically wasting your time. Air filter oil is sticky nasty stuff as you know. When you get that stuff in a tiny little circuit like the primary, its a pain in the ass at best.

I'm going out on a limb here but you may have the slide piece in upside down. There is a metal plate that will fall out when you pull the slide out. You grab the piece and hold it up to teh slide. You see what looks like the right way to install it by seeing the lower edge line up with the bottom of the slide. But this would be wrong. The hole in the plate goes at the bottom of the slide. With this piece installed this way, the

bike will hardly run, if it does at all.

Don't get frustrated with the bike. You have an issue that needs to be resolved (obviously, huh?). Once you figure out what has happened and get the bike set up right, you will absolutely love it!


Listen to MX Tuner's post!!!!!!!!!

I recently had the same exact problem with my WR. I think I tore apart my carb at least 10 times blowing out and cleaning the thing. The slide plate that Mark mentioned is really easy to goof up. It looks like just the opposite than the way it should be. My bike had the same symptoms: Only ran with choke,give it gas and died!!!!!

My valves get sticky from time to time and I loose compression every once in awhile. Next time just get the thing started and it'll work it self out and be fine.

Lastly, don't get so bummed out. I know you're frustrated but be patient. (and look at that plate)

Good luck!!!

DL :)

Relooking at this MX tuner is probably right.

I keep forgetting that assembling the carb incorrectly is possible, and easy to do.

no it ran funny like this before i took it all apart, its not like i put it together wrong and now it runs messed up , im just as lost as u guys r.


Check your pilot air screw adjustment on the bottom of the carb. This screw should be set approx. 1 3/8 turn out, depending on the alt. & outside temp.

One more thing to check.. make SURE the pilot jet isn't clogged. Had that exact problem on a two-smoke once and it had a little mung in the pilot jet. Any movement of the throttle would kill the bike...


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