well we had a problem with with my cam at first, i threw the chain, so got a new chain and tensioner, so now that worked, and stayed timed, but we got it started and then it stopped real abruptly, but it would keep kicking over, so eventually we took valve cover off, saw that none of the valves were moving, then saw the cam shaft wasnt moving and it had snapped in half, now i am wondering first why this happened, its possible the first time when it threw the cam chain, that one of the exhaust valves became bent, so im not sure if that would have been the reason, and my second is if anyone has an old cam shaft for a 91 650 dr, and then im not sure on which valve it is, probably be best to replace them all, but if you have any information on this is you could email it to me, or write it on here, that would be great, thanks