Honda 1982 CM450C Tapping sound

Hello,

I was wondering if anyone could help.

My engine seems to tap most noticably after it is warmed up. i did adjust
the valve clearance as stated in the clymer manual (intake 0.08 - 0.12mm
exhaust 0.12 - 0.16mm) and also adjusted the camshaft chain tensioner as
described in the manual..my question is how do i tell if it is the valves
tapping or something else tapping in the engine like .. the balancer chain
adjustment that is on the right side engine cover.. the little screw cap
(inspection)this is a different chain than the camshaft chain.


thank you for your help,
dave

 

Are the carbs synched? If they aren't, and either the camchain or
balancer chain are loose, out of synch carbs can cause all sorts of
rattling.

Taking the slack out of the balancer chain will make a lot of difference,
follow the procedure in the book, it's not difficult.

Did you adjust the camchain tensioner while the engine was running?
I found that is the best way to minimize camchain noise.

Adjusting valves is tricky, when the feeler gauge has a certain amount of
drag you have it right. The feeler should not slide loosely in the gap.

 

thanks mark,

i remember you from another question i had in the past, and u helped out
quite a bit.

i am not sure if the carbs are synched or not. but i did adjust the cam
chain while the engine was idle at 1100 rmp. and the feelers did have a
nice drag to them so i think they are adjusted correctly.

so i will try the balancer adjuster.. but it does bottom out.. so i think i
am going to have to adjust the adjuster plate.. which means i have to take
off the right side cover to get to it. will i need a new right engine
cover gasket or can the original be resued.

thanks again
dave

 

By far the WORST way to adjust the cam chain is while the engine is
running. If done this way the tensioner can get forced back in a very
loose adjustment. Best done with top cover off while turning engine over
with a wreb=nch and observing the tensioner travel and tightening it
when it is at its tightest position. Best to be shown this by someone
who has done it, if you can.

 

How many miles has it done?
Those Dream based engines had the camshaft running directly in the
head without shell bearings. The bearings wear and the camshaft
rattles.

Beware of over tightening the balancer chain.

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thanks bruce. i am not sure.. clymer manual says do it with engine on...
dont matter i can try it with engine off and top cover off. thanks for
your input

dave

 

It's tapping because it's tired of idling around waiting for you to
ride the damn thing!

 

Use a screwdriver as a stethoscope. Place the "working end" on the engine
and then put your ear on the handle. Keep moving the screwdriver around
until the sound becomes distinct. This will get you to where the noise is
coming from and then you may have a better idea as to what is making the
noise.

Good Luck.

 

If the noise goes away/gets quieter when the clutch is pulled in then
it's likely to be out of synch carbs.