Yoyodyne clutch parts??

[The Snowman]

Well, as some on here know, I had an "issue" with the Yoyodyne slipper clutch on my Aprilia at the 6/14 TTD event.

I thought that one of the pressure plate bolts had backed out and popped the center portion of the case cover off.

As it turns out, it was more than the bolt that's missing. It looks like the one whole set of parts that fits into the clutch hub went missing, and that's what most likely popped the cover off:



The rest of the clutch, incliding the pressure plate, sustained next to zero damage. The pressure plate has some cosmetic nicks, but it remains fully functional.

Has anyone here had to replace these parts on a slipper? I sent an email to Renz at Yoyodyne, asking him this question, but I figured that I'd query local riders as well.

[Paul_E_D]

I don't have a yoyodyne, but parts are available for my STM, they just come on the slow boat from Italy.

[Tricky Mike]

I disassembled my yoyo slipper before I installed it. It was super easy. Just some small clips (AKA potential shop missiles) to contend with. If you can source the parts you'll be fine with the disassembly.

[The Snowman]

Finally got around to taking the hub off (had to wait a little while for the universal basket holding tool). Thanks to Tricky Mike for suggesting to use a wrench to compress the hub spring retainers to remove the clips. I ended up using an 11mm box wrench for more leverage.

Damn thing snapped clean off...

[The Snowman]

Some interesting information . . .

I called Fred at Yoyodyne and talked to him about the sheared stud. He said that what happened to me isn't common at all. He said that usually when something like this happens, that it's the result of bad mechanics, such as using the stud to hold the hub in place while removing or installing the nut (at a force of 170Nm). Knowing the bike's PO, he didn't use this method, since he's pretty damned meticulous.

Anyway, I mentioned the scratching on the other 5 studs and told Fred that I was thinking about replacing those as well. He advised against it, saying that the wear I see is normal and he has seen bikes with tens of thousands of miles on them with worse scratching and none of the studs failed.

Also, the studs are put together by machine, they are threaded and locktited into position and then the base is drilled and a press-fit pin is pushed into it. I have already removed the press pin on mine in order to unscrew the stud. The new stud that I will get from Yoyodyne will not be drilled for the pin, since it's done after it;s screwed into position. He also advised not to reuse the press pin I have, but instead to drill and tap for a set scres and to red locktite the set screw into the base of the stud. He says that has worked the best. He mentioned that the threads in the base plate may get weakened by removing the stud and one of the reasons to keep the other 5 studs is not to weaken the rest of the threads. 1 of 6 is fine. 6 of 6 is not.