I have a 2000 yamaha warrior 350. I just brought, that had a bad bottom end. So I replace the bottom end, and now it want hold a charge, and the motor is not raising up it just sputtler and backfire. Seem like it outta gas, but its not outta gas, I clean the carb. The spark plug look good, what can the problem be.

 

A few ideas that come to mind are the parking brake rev limiter could be stuck, there could be a problem with the stator or coil, you could have a crack in the intake manifold, or your valve timing could be wrong.

 

Sounds like timing to me.

 

I got it running right it was the parking brake swith.....