8 plate clutch

Ratranger

XS650 Junkie
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I did not pioneer this set up, Ippytattoo used to sell the Alto 2.5mm friction discs as a drop in 8 plate upgrade and Hugh and a few other did write ups on machining the basket. If you machined the basket with the 2.5mm discs you could probably do a 9 disc set up. But using where Ippytattoo had posted the Alto part number I found out they fit the xs650 ans gs1000. I know the XS stock plates where used is a bunch of yamaha bikes, but for this to work you need the 2.5mm discs. This means finding the "extra plate" clutch kit.

So I started my 8 disc conversion by ordering APE kit CKGS1000. This is their extra plate kit that has the 2.5mm discs. The kit has 9 discs, but unless you machine the basket you only need 8. The stack height ends up being .4mm more than stock, so you might need to adjust your clutch after. But you just stack it in like doing a stock replacement, with an extra steel and friction disc. No machining, no fuss, took about 1/2hr to do.

I haven't ridden enough yet to do a full report, but it doesn't shudder and grab like the stock plates did cold. Seems to grab nice and linear, and no slip I can notice and I tried to make it slip.

Here are pics of it installed. You can also see I drilled out the stock screws for the clutch to take allen bolts.
 

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Cool! I used the ippytatoo pack on madness and it has been torture tested for several years and thousands of miles, never a slip, the previous clutch would not hold against the 750 even with stronger springs. Glad you found this replacement. Thanks for the write up!
Sorry, power is out, working from phone lol.
 
This is a very useful modification - that extra disc represents nearly 15% more torque capacity over the stock seven disc unit, even with the stock springs. A nine disc setup could transmit nearly 30% more torque ( 9 / 7 = 1.29 or +29% ). If you upgraded the springs, it would obviously be even more.

I suspect the folks who do a 700-750+ cc big bore upgrade would find it helpful in absorbing the extra torque.

Pete
 
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Very true, I did it because I thought I felt the stock clutch slip on me once after going on a longer ride. Since I'm going to the dyno tuesday I wanted to be sure the clutch would take it. The 8 plate is probably overkill for a basically stock rephase, but I'd rather not waste a dyno trip to a slipping clutch.

This isn't the cheapest option out there, it'll end up about $120-130 once you get the kit and upgraded springs, but it should take almost anything the stock cases can.
 
Forgive me if I missed it, but dId you use the stock XS650 steel discs or are the replacements thinner too?
 
have had ippys kit on my bike for yrs and really happy with it BUT did have intermitent shuttering probs after first instaling it , enough so i broke one of the springs , after settling down ,couple of thou kls was working great and very happy did the conversion
 
Believe it or not the Alto clutch plates have shipped!
Any takers around yet? 8 plates n shipping about $90 (my cost) for early adaptors. You will also need one Yamaha steel (not included).
I have 200 plates coming or about two dozen sets.
I have not ordered any steels from Yamaha yet.
 
Since this topic is back up and I finally got to do some work on the XS, here is the 8 plate setup installed with high ratio primary gears. I did skim a couple thou off the inner basket to get the surface running true and bring it down to stock height, not needed but I have the tools.
20200704_153909.jpg
 
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On the earlier how to. It says to rmove the spring clutch boss and adjacent...is that necessary for the 8pac, is was the spring clutch boss added in later clutches to help w smoother 1st gear engagement.
 
Depends on the year clutch you have. I think it's 80 and later has the spring damped plates. Earlier has 7 friction with no damper, and I think early oneals had a 3rd different clutch.
 
Ippy and the partzilla diagrams show 78 is the year the spring assembly was introduced.
Looking for verification.
 
All the parts manuals from thexscafe.com......Biker.net parts manuals also correspond with the list below

78E/79F Old style clutch hub

78SE/79SF/80G/80SG and on ........spring assembly Clutch hub

79F SII old style clutch hub.
 
I really want to do this for my chopper. Where do I get these parts lol. I wont be able to go over the forum for a few days.
 
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