i took off my head because i needed to do some valve work cuz its a gay four stroke anywyas i put it back together and i cant get the sproket back on the camshaft it needs to go only about an 1/8 of an inch but it wont give enough slack to get back on whats going on chain is still on the crank is the tensioner just that hard so i cant get it back on never had this problem be4 any help would be good. thanks guys, justin