I am doing a new piston and sleeve on my bike. When I'm trying to put on the new cam chain over the cams, I simply just do not have enough chain to get over them. The tensioner is not in. And I have triple checked the guide positions. It is seated on the crank sprocket. I even tried to get the old chain back on, and couldn't get that one over the cams either. Anybody have any clue.?