1972 GP292

[Ferg72]

Howdy all. Looking to bump up the engagement on my GP kidney clutch. Can you use any big washer under the weight tips or does it have to be the SR kit part. and is there a primary spring chart for these old clutches? Any info would be great Thanks. Setting up for vintage single ice oval.

 

[BornYamaha]

Howdy all. Looking to bump up the engagement on my GP kidney clutch. Can you use any big washer under the weight tips or does it have to be the SR kit part. and is there a primary spring chart for these old clutches? Any info would be great Thanks. Setting up for vintage single ice oval.

Hi Ferg,
This is what I have. You can install a washer or washers to raise the engagement. Yamaha say no more that 3mm thickness so you do not create spring bind when fully compressed. I reality I think you could go a fair amount more and be fine. It would vary from spring to spring. You could put the spring in a vice to see how much room you have at full compression. Adding shims will also raise your shift rpm some as well. If you are using an original spring it has probably lost some of it's strength over the years anyway so a little tighter squeeze might be a good thing. Many of these part #s are discontinued but if you contact a good Yamaha dealer they may be able to find a dusty one still on someone's shelf. This has worked for me several times.

Good luck.

 

[BornYamaha]

I don't know if you will find this helpful but it is an interesting read from back in the day.

 

[Ferg72]

Thanks for the info. The main thing i was thinking about was the SR cam 809 17623 00 or could a normal large washer thats cut to fit over the outer sliding half and contact the weight tips work?

 

[BornYamaha]

Never really had much experience with that type of clutch. Just the roller ramp enticer, YP, and newer. I just know the springs fit.