Hi, I'm rebuilding the top end of my XT350 as the Clymer manual states and I'm at the stage where I've put back the camshafts, lined up the marks (T mark on rotor, camshaft end marks and caps) but when I try to turn over the engine to see all works fine the chain jumps off the sprockets thus losing the timing. It says this should be done before the chain tensioners are fitted but time and again the chain jumps the sprockets as the cam lobes come under valve spring tension. Should I just line up all the marks, then fit and adjust the tensioners and see if it's still all lining up after turning the engine over by hand - or what? Any comments and help greatly appreciated! Thanks.

I recently bought an XT350 project and in the process of putting the top end together, ran into the same problem. I even tried having all cam chain guides in place and the tensioner bolted in. The cam chain still jumps when I try to turn the engine over. I've examined each of the guides and they all look like new. I'm convinced that the cam chain is stretched. At this point I am going to order a new chain and a new tensioner.

I recently bought an XT350 project and in the process of putting the top end together, ran into the same problem. I even tried having all cam chain guides in place and the tensioner bolted in. The cam chain still jumps when I try to turn the engine over. I've examined each of the guides and they all look like new. I'm convinced that the cam chain is stretched. At this point I am going to order a new chain and a new tensioner.

Hmmm the problem is that if the chain is worn out then so may the sprockets be...have you ever put a new bicycle chain on a worn out sprocket set? I have and it jumps like crazy...good luck though

...Paul