Well I picked up my first 4 stroke dirtbike and it skipped timing so I tore it apart and the engine would still turn over freely but the cam chain was bad and had some links seized on it. Replaced the cam chain and reassembled but when I got the timing set i tried to turn the motor by hand and when the camshaft lobs touch the valves it just stops moving and won't rotate. I haven't put much force on it at all. So I'm stuck and can't figure out why it's doing that. Could it be from not having the tensioner in? Or from turning the motor over several times after having the cam chain and cam shafts off it. I'm just stuck and can't figure this out. It's an 01 yz426.