1979 CB750K clunking noise

gimgim · Posted: Tue Apr 08, 2008 9:54 am Post subject: 1979 CB750K clunking noise

I've noticed today, on my way to work, it doesn't change when I rev the engine.
Sproket/chain or clutch basket?
What should I look for?
Thanks

hondacustom · Posted: Tue Apr 08, 2008 10:07 am Post subject:

clunking, setting still

clunking moving

or both ways

gimgim · Posted: Tue Apr 08, 2008 11:16 am Post subject:

Clunking moving. Still (with the enging on Smile

) it's OK

hondacustom · Posted: Tue Apr 08, 2008 1:45 pm Post subject:

sounds like your clutch basket, inside the basket , there are shock insulating rubbers, they tend to get hard and shrunken, [kinda like me ]

did you synch your carbs?

gimgim · Posted: Tue Apr 08, 2008 2:20 pm Post subject:

LOL...

I haven't synch'd the carbs yet, I have to take them apart again because #2 is slowly leaking.
Thanks for the suggestion though, I'll check the rubbers in the clutch basket...
It's still a work in progress but I am riding it anyway Smile

hondacustom · Posted: Tue Apr 08, 2008 2:39 pm Post subject:

the only way , you can check those rubbers is by taking apart a basket that is not meant to come apart

if your carb is leaking, its running on 3 cylinders sometimes, which causes rough running, which causes the chain which runs from the crankshaft to the transmission to slap and pound

this chain is kept taut by an oil pressure tensioned adjuster

fix your carb, set your idle @ 1500 , synch your carbs and all will be well

kinda like the knee bone theory

gimgim · Posted: Tue Apr 08, 2008 2:55 pm Post subject:

Not sure I understand...
Are you suggesting the noise is because of the rough running?

Sorry I wasn't clear, but the noise is not occasional but periodical, when I am riding. At "regular" speed (I have no tach or speedometer) it's about 1 or 2 clunks per second...
This is why I thought about chain/sprocket. Perhaps a stuck chain link...

hondacustom · Posted: Tue Apr 08, 2008 3:05 pm Post subject:

if your carb is leaking , it will run rough

if your drive chain is shot, well thats anothermatter andshould be replaced , before you hurt yourself