Name that miss!! 250R problems.

[RUNMYTA]

I am stumped with the infamous miss on my R. I recently had to replace the left case after a chain break that bust the bottom out of it. While I had the cases apart I noticed that the left crank seal was ripped all the way around. I replaced all bearings and seals thinking that the ripped seal was the cause of the miss.

My R runs great for about 8-10 min. Then developes a miss from 1/2 to full throttle. Idle to 1/2 it runs just fine. I also replaced the coil. If I pull over and put in a new plug and fire it up it will run fine from idle to WOT. Plug looks good. What would cause it to miss just at times? Maybe the main jet is a little lean?
TIA, MIKE

[AtvMxRider]

When was the last time the carb was cleaned?

[airheadedduner]

Your stator could be going. Sorry, I know you don't want to hear that.

[RUNMYTA]

I cleaned the carb while I had it tore down.

The miss feels like it is only firing every other rotaton.

What year and make of bike will the CDI work on the R? I can probably find one on a used bike at my Honda Dealership that they will let me use to eliminate the CDI.

[joeroadking]

sounds like a weak spark stator on the way out? If you are still running the on off stock switch on the handle bar try elimating the switch , by jumping the wiresI have had a problem here a few times as well. and this cured it