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A couple of updates for anyone who cares:

After my track day at Miller, I did a track day here at Firebird and after the 4th or 5th session the clutch started slipping big time under full power. Turns out that leaving just the base of the judder as a spacer was wearing a groove into the friction plates that it was stuck between, and the stack height was getting too low for all the plates to stick together and transmit power through the clutch. I took the judder base ring out and replaced it with the extra steel plate I had removed when I first installed it, and now the stack height is at 7.5 mm; pretty good. I took it for a quick spin up the street, and the bike actually wheelied under full power in second gear (hasn't done that before!). No slipping at all. So I'm now running the stock clutch pack with the exception that the judder spring and base ring are removed; I've only got steels and friction discs in there. My next track day is in April and I'll update after that.

Also: you can remove the clutch cover with oil in the engine; the level is well below the cover, especially when it's on the side stand.
 

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Help!

I installed my Yoyodine slipper clutch and have a couple of questions to those of you that have installed one. By the way, my clutch drum nut was a 30mm and not a 32mm.

The directions from Yoyo specify Loctite 620 on the clutch drum nut. This is a high temp retaining compound. Although it can be used on threads, its primary purpose is for press fit retaining pins, sleeves, liners, etc. My concern is Loctite specifies heating the object to 400dF for disassembly. I'm trying to figure out if I need to open it back up or not. Regular 'medium' permatex is good to 300dF, and its available, so that's what I used. I need to sort this out, I'll be 'on track' in two weeks. I also installed the stock washers; both the flat washer and the 'market' washer with "out" labeled on it. this causes the nut to just barely (or just barely not) fully engage all the threads of the nut. I am wondering if the first washer (flat one) could be removed.

Did any of you use a thread locker? If so, which did you use? Also, If the nut was to come loose...would it lock in gear or permenantly slip? If this were to happen, How deep would the damage be (replace entire clutch assembly or have to pull the motor)?

thanks in advance for your time.
 

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I didn't use any loctite and so far have 4 high-abuse track days and no problems. If the nut did come loose, the clutch would just start slipping and eventually no power would flow to the transmission at all because the hub would just spin on the crankshaft.
 

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Disregard last post; looks like the hub, or inner drum, splines onto the crankshaft, so the clutch would still operate because the hub is still spinning with the crank. Obviously, the biggest problem would occur if the nut came all the way off while the engine is running. But the clutch should still work even if it comes loose.
 

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The Yoyodyne came with a spring washer... where does it go? The instructions that came on the CD are HORRIBLE. Translated very badly into english...

Thanks!
 

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Nice and helpful tutorial. FYI - I mounted a STM on my bike this weekend and its quite different to the design of Yoyodyne and Sigma. The dismountal of the clutch is identical, but STM have a totally different spring design. The only thing used from the OEM is the plate package (judder springs excluded), the pull-rod and the bearing.

Thank You, BrettMess:thumbup:

EDIT - some pictures to display the mounting of a STM instead of the Yoyodyne can be found in the thread http://www.triumph675.net/forum/showthread.php?t=21942
 

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Nice write up on the slipper clutch....except please use the correct part name so noobs don't get confused. The thing you are calling a "drum" is a clutch basket.

Unless you are in the UK. :rofl2:
 

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Gonna pull the one out of my bike and put it into a newer, lower mileage engine, so I'll be utilizing the clutch plates out of the newer engine... I didn't install the first time, any pointers to help with dis-assembly & re-assembly?

Also, what happens if the judder spring & friction plate were not moved to the 3rd position, the stealership AZ Stupidbikes seemed to of not installed it correctly...
 

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Talked to Yoyodyne and they said no big deal, but I will be reinstalling correctly... I also had a 30mm nut... Anyone else? Is that just a misprint??
 

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Did you use the conical washer that was provided by Yoyo for the clutch basket or re-use the Triumph washers that were on the stock basket?
 

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wow, great write-up. how much was it?
 

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The directions from Yoyo specify Loctite 620 on the clutch drum nut. This is a high temp retaining compound. Although it can be used on threads, its primary purpose is for press fit retaining pins, sleeves, liners, etc.
when i worked at Tesla and we were doing transmission builds, we used the 620 stuff (its green) for tapped threads. since the clutch generates a bunch of heat, best not to skimp. McMaster-Carr sells it for~$15.
 

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when i worked at Tesla and we were doing transmission builds, we used the 620 stuff (its green) for tapped threads. since the clutch generates a bunch of heat, best not to skimp. McMaster-Carr sells it for~$15.
I sell it at NAPA Auto Parts aswell Permatex section
 

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When installing the Yoyo clutch basket, did you:

  • Re-use the stock flat washer and belville washer before putting on the 30mm nut
  • re-use the stock flat washer, belville washer, AND conical shaped washer that yoyo provided
  • or just use the conical shaped washer that yoyo provided?

Thanks!
 

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When installing the Yoyo clutch basket, did you:

  • Re-use the stock flat washer and belville washer before putting on the 30mm nut
  • re-use the stock flat washer, belville washer, AND conical shaped washer that yoyo provided
  • or just use the conical shaped washer that yoyo provided?

Thanks!
Still interested in help with the question above. :cool2:
 

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Feedback on mine.
great write up. torque to 8nm as per yoyodyne instructions. they are held by spring pressure anyway.
use old flat and bellville washers. yoyodyne conical remains in box.
relocated judder springs/plates as per instructions

works a treat. should have done it ages ago.
great sticky!
q
 

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I just installed the Yoydyne yesterday and wanted to say thanks to Brettmess for taking the time to do an excellent write up.

I do have a couple of questions for those with experience.

I installed in a brand new bike, so no miles or wear on the original clutch pack, and found that even after removing the judder spring and thin plate, that my stack height was about 2mm. It says to have a minimum .4 and ideal is 1mm but nothing about a max.
Is 2mm ok or should i remove a friction plate?

When removing plates, can you put two friction plates together or do you need to put 2 steels together?

Once completed I had to take quite a bit of slack out of the cable. Is this what you all found?

Lastly, I have not been able to road test, but when running on stands, I could feel a pop / click in the lever and also hear it in the clutch pack. From what I've read this sounds like it is somewhat normal, but thought I'd ask here to see what others have experienced. Also if normal, do you think it is worse without having a load on the drive train, being up on stands?
 

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Installed mine with a new clutch pack and did not measure stack height...I have a similiar little "notch" at the end of the lever pull. Everything works fine for me...Good luck!
 
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