Motorcycle Repair: cb 900 Honda exhaust cam install chain, 1980 honda cb900, honda exhaust


Question
I am attempting to re-assemble my 1980 honda cb900 and find that the exhaust cam chain is too tight to allow normal assembly.  I have the chain guide and chain tensioner in place and depressed or adjusted according to the shop manual, but the chain is way too tight once it is on the sprocket to slip on to the cam.  What am I missing?

Answer
Hi Tom,

(Just revised this a bit as the exhaust tensioner
has to be pushed down to release cam chain tension.)

Sometimes the tensioners are just sticking when you think
they are fully retracted.  The tensioner screws make
a dimple on the rod that makes it stick in the usual
position it is locked to.

I would turn the engine slightly
back and forth to make sure the chain is seated on the sprockets
and try pushing the tensioner down with something
like a piece of hardwood that won't damage or splinter.
Have someone help you if possible to lock the tensioner
in place when it is pushed firmly down.
If the tensioner locknut screw is loose it might
be the rod is sticking and stopping the tensioner.

If the camshaft is not seated well it might help to tighten
down the camshaft holding caps to pull the shaft downward
so the chain will fit. The cap bolts can strip out easily
so be careful with those.

It should go together if you can get the tensioners to back off far enough
without causing any damage to them.

Wayne S
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