Topic: 79 CB650, help please with clutch issues

[Barneycanoe]

 
Hello, I own a 1979 CB650 (Second time around, that model was my first bike in 1979!) I have two questions for my fellow SOHC enthusiasts.

First, when taking off from a standstill, I have to rev 3,000-4,000 and sort of slip the clutch to get going. There is not a clear engagement point. At all other times and in all other gears, clutch does not slip and gear changes are fine. The clutch is properly adjusted as per the Honda shop manual. I have read somewhere that this is not abnormal for the 79 CB650. Can anyone confirm?

Second, when the bike is at idle, warm or cold, I am getting this sort of bock-bock-bock-bock-bock sound. When I put a screwdriver on the cases I can hear nothing abnormal or knocking. Just this morning I realized this sound increases when the clutch is out (in neutral) and diminishes when the clutch is pulled in. Does anyone have any ideas?

Bike has 9,000 miles on it and is in excellent mechanical shape. I've adjusted everything including valves this year.

Thanks

Dave

Ontario, Canada

[cb650PK]

Did you synchronize the carburetors? Did you tensioned the cam chain? If yes to both, wear full face helmet and ear plugs(that is what I do, since my bike makes the same noise.I believe it's the clutch.) If you want quiet bike buy Suzuki

[DsKing416]

My CB550f was doing the same thing then it stopped one day, I just broke open the cases for a rebuild. I found that a piece of the cast aluminum case that holds the kick-start return spring in place broke off. It apparently stopped the noise and the clutch interference when it rattled its was to the oil pan. You could check that out next oil change. no garauntees but that was the same problem I had and it's an easy fix. The kick-starter still works so no fix really just remove the aluminum.

[cb650]

There is some clutch noise normaly.   Adjust the clutch then the cable then at the lever.  I jet mine going at 2k but then I've had one forever.