engine will not run right????PLEASE HELP

[jimbo1073]

rebuilt motor and can not get it to run right. misses in mid range and no top end. changed the whole electrical system, rejetted many times. up to a 178 now. before rebuild and bore i was running 168 main jet. new reeds also. ive rebuilt this motor several times and never had this problem. should i rebuild the carb? what can possibly cause it to run this way. its runnin lean but when i move the clip to the leanest position(top groove) it runs better.still not good at all. ? 87 trx250r fmf pipe, 80over wiseco piston,cool head (21 dome), no airbox lid, Vforce reeds

[sangheraent]

sounds like you have an air leak. do a leak down test on the motor.

[Honda 250r 001]

I had trouble with a CDI box i bought from dynatek. I put it on and within an hour if ride time it started missing out in the midrange and wouldnt hardly rev up to high rpm under load. You didnt happen to put a different CDI on it did you?

[jimbo1073]

no test and i dont know how or where to get this done here in central florida. yes i changed cdi

[leager-n-ky]

might seem silly, but have you checked your gas for water ? had this prob once yrs ago..

[bansheeboyo]

did you ever get this fixed ?
if so what was the cause of the problem as im having the same issue
cheers scott