Just wont rev

[300ex07]

Runs perfect until half throttle and then it just cuts out. Reeds look good. New cdi. different coil, Different Harness. I have tried several jets from 178 to 195 and the engine still wont rev. To I decided to take the filter off and look in carb. When I started the bike and opened throttle all of the way there was exhaust comming out of the carb? Dont have any idea what is wrong, I need help bad.

[jon370r]

Try gaping a new spark plug at .018 to .020.

[300ex07]

but why is the exhaust coming out of the carb

[rea]

That dont seem right you would think your reeds wouldn't let it threw if they had pressure from the other way it would push them closed

[300ex07]

would having to much compression make this happen

[jon370r]

Its most likely not exhaust. Is just air and atomized fuel mist and some is normal. You could try a new set of reeds or a stiffer set that close faster but that will give you more topend revs.

[300ex07]

Any ideas why it cuts out though. I've tried everything, new dyna ignition, new coil new plug, new wiring harness, new carb, new pipe, every main jet under the sun, everything is new. Have not been able to get it to rev out since I bought this cylinder from M.E.T

[300ex07]

bump

[kiesta00]

1)Are your reeds good?
2)intake boot leaking?
3) are your ground points clean and on bare metal? no painted/rusty surfaces
4)any leaks from the cylinder? do a leakdown test

pull the stator cover and look for anything broken/loose in there. I had the same problem; my intake boot was slightly ripped at the top and the reeds were cracked. good luck