hey guys,

I have a 91 trx250x and about three months ago it just died on me, I was able to pop start it and ride it but I had to keep the RPMs really high. Today I finally got around to cleaning the carb out and put a new spark plug in there but it didn't help. I tried kicking it for a while with no luck so I was towing it behind another quad and it finally started. When I had it running I had to keep the throttle wide open to keep it alive, but it just sounded terrible it was coughing and backfiring the whole time.

I am going to tear down the motor tonight and see whats wrong with it. Is there anything I should pay special attention to? Is there any way the timing could have gotten off track mid ride?

 

Although it could be a problem with the engine, it could be electrical or even fuel again, dirt or water can block a newly cleaned carb. Check valve clearances and do a compression test before tearing into the motor. The later, lengthways crank 250 has a dodgy timing chain adjuster but I think your engine will be similar to the 300 which was fairly bullet proof.