BIG problems please help!!!

ok so I took the accel pump out and the linkage up by the the pulley and I cleaned it up. I put it back together and couldn't get it started!!! I noticed also that I didn't need to use my decompresion lever to kick it over(remember that this bike ran primo three days ago I just thought the accel pump was sticking) The plug was wet . well I took the carb back apart and checked it out put it back together put it back on the bike and it started but wouldn't idle and was sputtering bad. I had to turn the the idle screw in about 8 turns then when I reved it it would idle to high then it would go down it fluctuated all over. when I reved it up a lil black smoke came out so I thought it was running rich but i checked plug and it was tan like perfect well I hope this is enuff info to get some help?

I am scared!!!!

Mike 01 wr426

I had similar symptoms after installing the P-38 mod and doing other maint. to my YZ250F. I also seemed to not have any compression for about 50 friggin' kicks. Pulled the plug, but it was dry, suspected air trapped in fuel circuit or something. Finally got it started after about 100 kicks, thing has run fine every since. I was really bothered by this for a while, but seems O.K. now, bike starts on first or second kick. Good luck figuring this one out, let us know what you find out...


If there's a way to crash, Ill find it...

If a bike floods out it may lose compression when kicking it over. The compression will come back up after you get it running. The next time kicking it over it feels back to normal.

Check for air leaks, hot start pulled, choke pulled, anything you messed with. Hope you didn't take the plate out and turn it UPSIDE DOWN! :)

Mr. Bandicoot,

How do you like the performance after installing the P-38??



Life is too short, work hard

Sponsored by Yamaha of Cucamonga, Larry Roeseler's Stroker Fourstroke Speed Equipment and Answer Racing


I did several mods all at once, P-38, Dr.D pipe, DSP half c/f airbox, remote hotstart(Terrycable), Race Tech gold re-valve on forks and shock. I will have to say that I love the performance of the bike. I have tons of power everywhere and throttle response is exceptional. I had to get used to the bike all over again, but that's just part of the fun. I really have had to work on throttle control more now than before due to the added wheel spin. I still have the stock 48 tooth sprocket and now the thing climbes everything like a billy goat. Rode some cool trails in South Dallas on Tuesday and I really love the tight twisty stuff now. I am very, very happy with my YZ250F...



If there's a way to crash, Ill find it...

turn what plate upside down?

I had some problems like that a while back after I pulled and cleaned my carb. Hard to start and wouldn't run. Clark told me to double check the cover plate for the accelerator pump. There should be a very small O ring that fits in there. Well, there wasn't one, I had lost it when I cleaned it. I picked up a new one (and several more) and it ran fine after that.

I know of at least 2 cases where guys took the throttle valve (slide) out and when they put it back in they had the backplate upside down. This caused the bike to pop, die at idle and run rough. I can see where this would be easy to do because if you didn't look closely when taking apart you would assume that the "pointed" end of the plate would align with the "pointed" end of the slide.


I am at work and I want to fly home and see if thats what I did!!!

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