Motorcycle Repair: Honda 400A knock, cb400a, bikebandit com

Question
I purchased a Honda CB400A 1978 with 5100 miles in very good shape,needed full choke to run so full carb rebuild with all new parts also found right manifold leak,fixed that now runs great starts easy but has a knock in engine,gets louder as it warms up,loud at idle,changes to a purr at speed,At certain no load speeds no noise at all.I read somewhere someone had a exhaust leak that sounded like a knock is this possible? the pipes have been off 2-3 times and I can't find anything wrong with it.

Answer
Stephen,

-many things can make noise in an engine,
in your case I would suggest it might
be the balancer chain is loose. It can be
tightened if the chain is not worn out.
Take it to a good shop and let the tech
listen to it. The chain should be replaced if
it can not be tightened.
The adjustment is made inside the clutch cover.
http://houseofmotorcycles.bikebandit.com/parts/Honda/CB400A/1978/2330570

-Loose cam chain is another possibility
if adjuster is stuck.
-If it is a light tapping or ticking
noise, that is just valve clearance,
a normal sound for these engines.