Zean's right, that could definitely cause your problem. Also check to make sure that the sprocket on the wheel and the cog on the motor are in line. If they aren't that would cause the chain to behave like what you're seeing also.
I checked to make sure they are in line
But i have a problem.
When i put the chain tensioner on the bottom.
The thing is not sitting straight
How could i bend it to make it fit the chain right?
Thanks for any advice guys
BTW i dont have very much low end on the bike.
It only has top end but it's sort of hard getting there lol.
It helps to assist the motor when i first start riding
Also i burned a hole in the paint near the downtube
The exhaust was alittle to close LOOOOL