Hi. My engine have a rattle noise from the left side of the engine but its only there when i rev the engine not on idle. I have checked the cam chain and to me its tight but how do i know if its to lose or tight ? I can make it tighter if i whant but the tensioner spring should add the right tightnes right ? The bike always starts on first kick. It takes no oil. Dont smoke. Runs just great i think Good idle and realy strong from bottom to higher revs. I did think mabe the piston is slaping but if it did do that it should run wery bad to right ? Take oil and hard to start. Or do i need to check the piston ? Sry for my bad english but i rly need to know what i should do.