Topic: CB650C - Not enough slack on cam chain to fit on sprocket and cam

[650N00B]

Hello,

I'll try my best not to waste time on this, but I haven't been able to find the correct help in this forum, other forums, youtube, etc.

I have a 1981 CB650C. Did a top end rebuild, everything going well. Went to put the cam chain on the sprocket, then on the cam and bolt down. However, there is enough slack to get it on the sprocket, but not for putting the chain on the sprocket, then putting the sprocket onto the camshaft.

What I've checked.
-Engine is TDC as it should be.
-Camshaft is in the right orientation to the head.
-Chain guide and tensioner seem to be fitting correctly.
-Can turn the engine and get the chain to turn with it. So hopefully that should be fine.

What i haven't done.
-Torqued down the cylinder head bolts yet. Maybe i should but I've seen people say not to do it yet.
-Haven't tried removing the timing guide. I don't see how i would get it back in after getting the chain, sprocket, and camshaft installed.
-I've seen a lot of people discuss the chain tensioner. I know there are differences between years and models. Mine doesn't have the adjuster where you use a flat head. Just the bolt and a nut. Loosening, tightening, and pressing it in to release any slack makes no difference.

I'm almost at my wits end here. Any advice, for something i haven't already done, would be greatly appreciated. I feel like I most likely overlooked something stupid, or missed a simple step.

[Sw1ssdude]

i just did the same thing on my CB550. it was the fiddliest sh*tshow.

problem was that i had to rotate the sprocket so it sat in one of the cam  lobe cutouts, so it sits a bit lower, this way, i could get the chain on the sprocket. to clock the sprocket to the Camshaft, you need slack in the chain, which i got from gently pressing the chain and tensioner in with a long and clean screwdriver as a lever (not pry-bar)... very gently! the manual says for removing the camshaft you should lock the tensioner in its slackest position, they forgot that part in the assembly section. but it helps remarkably...

i too wasnt able to push the sprocket on the flange, but i got close enough to fit the screws, and pull it on with them.

hope this helps.

[bryanj]

Cant remember on 650 but 500/550 the front guide goes inside the chain and if fitted outside gives exactly your problem