i thikn im onna rejet my freinds rappy, ive never odnt i befre, if it is alittle lean, is it bad for the engine like on a 2 stroke, or well it be ok, cause i have a banshee and i know if ur to lean u can pop a piston.... and if u just intall a k&n should u rejet, and if so how much

 

If alls your doing is putting in a K&N and not modding the air box or anything else your jetting will probably be fine.