Motorcycle Repair: sputtering 3500 rpm, crankcase, cdi

Question
hey Mark my 1986 xt 600 sputters at 3500 rpm,and on the highway i just stops running .It has a super trap exhaust and has just been rejetted,new cdi and coil .Any suggestion as to what I do next,thanks

Answer
Check to make sure the crankcase is not full of fuel...This is pretty common for the fuel to drain into the crankcase and NOT allow the engine to "rev" up...Also, make sure the air box is in tact and it is properly sealed, this is also common...

Hope this helps!

~Mark