i have an 01 banshee with a few mods. i recently rebuilt the hole motor from the crank up this last spring and ran perfect for a few months.
now when i ride i cant go anymore than that first little bit into the powerband and then it drops a cylinder and i have no idea why. ive been through everything. its got gas. the coils brand new, and the gaskets are all good... everythings good. i just cant seem to find the problem. idk if its electrical either cuz ive been through the wiring also. just wondering if someone could point me in the right direction before i have to bring it in to a yamaha mechanic??? any new direction would be appreciated.
thanks rick

 

Does it die, or just fall on its face? It could be electrical, stator problem maybe, or cdi, but not likely. Sounds like your carbs are out of sync or maybe a leaky boost bottle fitting. Check those and let us know how it goes.

 

First thing I would do is a compression test. Have you done that yet?

 

did yo try checking the air filters? that happend to my buddys dirtbike before and his airfiltercome off where it ataches to the carb. im not sure if that could be it but jst a suggestion.

 

Check the reeds also, I've had a set once that one leaf was cracked and would idle up to the powerband and then just fall flat.

 

a bad stator or cdi can do this

 

Clean the carbs completly, and get new plugs. Had a similar problemb, and that fixed it. Rule out carburation and spark first, then compression, last on the list would be the CDI