I'm thinking it's in the tranny. I was racing my 250 on sunday and it seemed like every few seconds the rear end would lift a bit. Felt kinda like the chain was jumping .

All told, beat the hh by 3 buggies in 300 ft

did it do it on flat ground?

Flat road no bumps at all. Off road I never noticed it but then its bumpy. On the asphalt it did it a few times

When it happens did it seem like it wanted to kill the engine?

No not at all. The rear raised up a bit and felt almost like you pushed in the clutch then intantly released it. I dont think the motor skipped a beat

if you were missing teeth it would do it all the time.If you had floating junk in your trans Iwould think it would want to kill the engine .Did you try taking the shifter cable off or loosening it alot.Maybe going in and out.also make sure your sprokets are inline and tite.

check the chain adjuster for cracks and check to see if the motor mounts are moving

Another thing, I tried to get in Rev but it would'nt go. Then it finally went and would'nt go back to drive. I turned off the motor and it wnet right in. The cable was'nt tight either

All thats good Eric

I forgot yours had reverse, how high is the idle, might have to back it down a tad

Yea I think thats the problem with the shift. That would'nt affect the WOT issue. I turn the idle up till it warms and I never put it back. She dont like to idle cold and I just hate how high it idles on choke