Rough-running 250X

[BigDaddyCMU]

I have a 1987 TRX 250X. I bought the bike from a friend who had just had the top end rebuilt with a new Wiseco high compression piston, Web cam (yeah I know not the best brand), new valves, springs, etc. After he got it back, it never ran right. He just thought it was a jetting problem. I messed with it forever, figuring it was the carb. I tried a ton of different jetting combinations, and tried a 400EX carb, but it never changed. I then took it to a local guy that builds racing bikes. He looked at it, and checked everything mechanical, and found nothing wrong. It still won't run right. It will start on the first kick with no choke, and idles OK. It runs very rough at middle and full, like it's bogging, but it's not. When held near WOT, it surges, and the RPM's go up and down, similar to a rev limiter. I was almost sure it was carb problems at the beginning, but now I think it may be something electrical. Has anyone else had a similar problem? Could it be a coil or cdi box? I'm totally mystified as to why it will not run correctly. Any help would be greatly appreciated.

[efilnicafesin]

I had something similar, and from what I've read, the 250x's have a problem with the stator coil going bad.... I replaced mine, and that didn't fix my problem.. Mine ended up being engine related :( The stator is easy to replace. It may also be a CDI problem..

[ghak99]

Originally posted by BigDaddyCMU
Web cam (yeah I know not the best brand)

I got to ask, what is your reasoning behind this statement?

[ghak99]

Originally posted by efilnicafesin
I had something similar, and from what I've read, the 250x's have a problem with the stator coil going bad.... I replaced mine, and that didn't fix my problem.. Mine ended up being engine related :( The stator is easy to replace. It may also be a CDI problem..

He is correct, check the stator and pickup, but I think your problem sounds carb related. Have you tore it down and cleaned every bit of the carb?

[BigDaddyCMU]

Well just from what I've heard, because the Webs are regrinds, some people say they're not as good as the brand new cams. I've heard hotcams are better, but I don't think they make one for the 250x.


I tore the carb down, and put it back together. I'm thinking about getting another carb just to try it out and see if that makes a difference. If not, then I know it has to be something else.