SZR 660 cam re fit

[Stuart]

Hello, first time of using this site, in need of some help. I'm trying to rebuild an SZR 660 engine top end, I can't find the way to get the cam back into the head, and get the chain on the sprocket. Obviously it can be done, as it was, I've watched all the you tube posts and films I can find, but none actually show the cam going in. One of the problems is the chain coming off the bottom sprocket, bloody morse chain, also can't find the way/angle to approach the cam bearings to wrestle the cam in. Does anyone have experience or knowledge of this procedure, better still know where I can find a video of it being done, I'm a retired mechanical fitter machinist, with years of experience of building and racing motorbikes, but this bugger is beating me.
Stuart

[droy]

it can be done with cam chain tensioner removed and a lot of feting of the cam.

Other method is the take the cam sprocket off and install the cam and then install the cam sprocket but be carful that you don't drop the bolts into the bottom end.