Shim a clutch spring?

[redblk63]

At the risk of offending someone, does anyone know if the CB77 clutch springs can be shimmed to reduce slipping? (engine # CB77E 1005392)

I remember that all (just 3 so far) my CB77s that I have had since 1967 had weak clutches. And going for weeks between rides seems to make it worse. My clutch disks have decent material thickness, but cannot withstand full throttle at the RPM at which torque peaks without slipping.

Back in the day, adding springs from Barnett was the hot tip. Being one to avoid spending a dollar whenever possible, I figure I can increase the spring force by adding preload using a washer under each spring. Of course, I would check against spring binding at full release, and I realize the lever force required will increase. :-)

Does anyone have experience with or theoretical advice on this bold suggestion?

Larry - Pasadena-CA-USA

[LOUD MOUSE]

Yes we added spark plug washers.
The clutch didn't slip but your left hand was shot after a good long ride.
The 820 spring is shorter/thinker wire and may be what you want. ............lm

At the risk of offending someone, does anyone know if the CB77 clutch springs can be shimmed to reduce slipping? (engine # CB77E 1005392)

I remember that all (just 3 so far) my CB77s that I have had since 1967 had weak clutches. And going for weeks between rides seems to make it worse. My clutch disks have decent material thickness, but cannot withstand full throttle at the RPM at which torque peaks without slipping.

Back in the day, adding springs from Barnett was the hot tip. Being one to avoid spending a dollar whenever possible, I figure I can increase the spring force by adding preload using a washer under each spring. Of course, I would check against spring binding at full release, and I realize the lever force required will increase. :-)

Does anyone have experience with or theoretical advice on this bold suggestion?

Larry - Pasadena-CA-USA

[G-Man]

Larry

This is an interesting bulletin from Honda UK from 1966 regarding clutch slip with the 5-speed gear set.....

My 1961 CB72 (with 350 kit) had some thick spring washers under each clutch spring but, as LM says, those stronger clutch springs should help.



Here is the hub that they are referring to, I think.... Also the pressure plate with the holes works in conjunction with that to centrufuge the oil away from the plates.



G

[cknight]

If you can find them, use the solid copper spark plug washers. Much better than the crush type. Regards, Chase

[leonvjames]

Lots of years ago, I made spacers from pieces of pipe, electrical conduit I think. Made the clutch a bit harder to operate but you soon get used to it. Somewhere between 2 to 4mms thick.

[redblk63]

Wow, thank you guys.

It is encouraging to find that others have gone before, and found success. With respect to Honda's well thought out solution involving new components, I think I will go the simple route. The idea of defeating the oil holes to increase clutch bite makes me nervous. That is educational to read, though.

Four mm of pipe would add a lot of preload alright. Maybe if I were racing..., not going to happen.

I think it will be the spark plug (non-crush) washers for my Super Hawk!

[leonvjames]

It is a long time since I saw the spacers and I don't really want to take the bike apart just to check, start at 2mm.
Leon.