Interest in 8 plate clutch conversions?

Would you be interested in an 8 plate clutch conversion?

  • Yes! my money's on the way

    Votes: 18 60.0%
  • Are you kidding? Those are not genuine Yamaha!

    Votes: 0 0.0%
  • Clutch? no one ever has clutch problems!

    Votes: 1 3.3%
  • Maybe later on, after I get my build/restore done and on the road.

    Votes: 11 36.7%

  • Total voters
    30
I think it might work. That 3mm stock plate thickness is the "new" spec for them but most used ones I've checked still measure at that. 6 plates @ 3mm would "fill" 18mm of space. 7 Alto plates @ 2.5mm would fill 17.5mm of space. But, the wear limit on the stock plates is 2.7mm, so 6 worn to the limit would "fill" 16.2mm. The clutch would probably still be functioning (although maybe slipping) at that wear limit stack height, so it just stands to reason it would function fine with a 17.5mm stack height.
 
Yes - you'd also be adding another 1.4mm steel, so maybe the stack would end up too thick. The stock 7 plate set-up is 21mm. The Alto 8 plate + an additional 1.4mm steel is 21.4mm. Apparently there's enough clearance for that to work. On the 6 plate, you'd have 18mm. 7 Alto plates + a 1.4mm steel would give you 18.9mm. I don't know if there's enough space under the cover for that to work. It might fit together but when you pulled the clutch lever and the pressure plate moved out, it might hit the inside of the cover, like this .....

yofTGSu.jpg
 
Funny you bring that up..
One of the oil changes on Madness the oil looked like metallic paint, no other issues next change was fine.. I should look inside that clutch cover!
 
Well, I pulled out my notes from several years back when I did some pressure plate movement measurements and also checked the clutch cover depths .....

U2fQDFr.jpg


I found a slight difference in cover depths between my original '78 cover (68mm) and the '81 or newer oil sight glass cover (70mm) I was swapping on. Relaxed or engaged, the pressure plate sat about 64.6mm above the case gasket surface. Most pressure plate movement I could get (with worm and cable adjusted snug) was about 1.54mm. That would move the pressure plate out to just over 66mm from the engine case gasket surface and leave just under 2 to 4mm of space between it and the cover, depending on which cover was used. So, it looks like that additional .9mm of stack height wouldn't be an issue.
 
Well, I pulled out my notes from several years back when I did some pressure plate movement measurements and also checked the clutch cover depths .....

U2fQDFr.jpg



I found a slight difference in cover depths between my original '78 cover (68mm) and the '81 or newer oil sight glass cover (70mm) I was swapping on. Relaxed or engaged, the pressure plate sat about 64.6mm above the case gasket surface. Most pressure plate movement I could get (with worm and cable adjusted snug) was about 1.54mm. That would move the pressure plate out to just over 66mm from the engine case gasket surface and leave just under 2 to 4mm of space between it and the cover, depending on which cover was used. So, it looks like that additional .9mm of stack height wouldn't be an issue.
So 7 plates and one used steel? shipped $84 sound OK?
 
I wouldn't need the steel plate, I have extras, but let me give it some thought. Both my clutches are working pretty good. I haven't been into the '83 one at all so no telling what the P.O. replaced, if anything. The starter on that bike also works quite well with minimal grinding so I didn't plan on going in there right away. Besides, I'm knee-deep in muffler baffle work at the moment, lol.
 
Gary, don’t hold one for me. Funds are too tight right now. If someone wants mine and has money, let it go. I took a hard hit when my Geothermal AC went out over the holiday weekend. That and I already over extended myself on Mrs Willis 40th birthday present this weekend. If I can come up with the scratch I will reach out and see if you have any left.
 
Great Beags! No worries Willis, good luck with the AC! Man it's a scorcher, storms rolling through here now. but right back to hot tomorrow.
 
Last edited:
Received Alto plates on Monday. Installed this morning.Went for a test ride this afternoon.
I had asked Gary if the would work in a early clutch. He wasn't sure. I think they would with no problem if you replaced the steel plates with the newer thinner ones. Since I knew I had a broken cush spring and a couple of loose ones I was going to replace the outer basket. I liked the design of the oil holes and the fact the outer pressure plate locked onto the inner basket in the newer clutches. I picked up a few clutch assemblies during the winter. I ended up putting the Alto plates in a 76ish clutch.
Ok new clutch in, fresh oil and out for a test ride. 15 miles on county and city roads (30 to 50 MPH), 10 miles on Highway (60 to 65 MPH and then 15 miles home on the local super speedway (70 to 80 MPH) .Is it better than what was in it? NO. My old clutch worked just fine. It had Barnett fiber plates in it. Does it work worse? NO. It engages smoothly and doesn't slip. Does everything a clutch should do and nothing it shouldn't. Now my engine is 2nd over but stock other than a 2 into exhaust. Is it an improvement? I can't say it is unless you are having a slipping problem. Some of the guys that bought the plates have higher horse power engines than I have and ride more aggressively than I do. Be interesting to get their thoughts.
Time is the final judge. My old clutch lasted 40+ years, don't think I'll be around to see if this one lasts as long. :(
 
I did forget to mention the "Cool" factor. You can offhandedly mention to your friends that you have a 8 plate clutch. Bigger is better and more is also better.:) They don't need to know your engine doesn't make enough horsepower to need it.
 
A free trip to beautiful, scenic and exotic.....Dixon, Illinois!

...in the rain, at night...on all the twisty mountainous roads in Illinois...
 
Last edited:
Back
Top