Product Reviews


Product/Service: Yoyodyne Slipper Clutch
Manufacturer/Provider:
Yoyodyne
Reviewed by:
Jeff


What is a slipper clutch?

Glad you asked. It's a neat little gizmo that allows the clutch to ratchet forward with a wheel speed greater than the engine speed. That equates to having the ability to downshift multiple gears VERY quickly without locking the rear end or hopping it around. Engine braking still exists and is quite effective, but now you don't ping off the rev-limiter, but rather about 2/3 of the RPM range.

Again, looking for ways to cut down on lap times in a repeatable fashion, I started looking at a slipper clutch. The choices in slipper clutches are pretty slim. The main 2 brands are STM and Yoyodyne. I leaned towards the yoyodyne because I've dealt with Fred Renz, owner of yoyodyne, and his products are VERY high quality. Plus the price was about $300 less (retail - $795).

When I got the clutch, I held it up and proclaimed "that's it?!?!?" Nothing more than the center clutch drum and the end pressure plate.

Install was simple plug-n-play. Remove the old clutch, paying VERY CLOSE ATTENTION to where all the plates & steels go, and what direction the washers go as some are 'sprung' washers (cupped to provide a pushing resistance). Make sure you install the washer BEHIND the clutch basket exactly as the OEM install was.

On my 05 600rr, I ended up leaving OUT one thick washer on the INSIDE of the clutch drum. It was one between the clutch drum and the stake nut. I did this so that I could stake down the stake nut on the shaft. The inside of the slipper clutch drum has a little groove which is raised up and takes the place of the washer.

So, does it work?

Well, the one thing I could feel was a click in the clutch lever as I'd pull it in. I'm told this is normal. Getting it out onto the track I figured I'd hear it or feel something, but I felt & heard nothing. Well what the heck? Is this thing working?? So down the cold track I went hard in 4th gear. I grabbed the brakes and dropped it to 1st and dumped the clutch. The back tire locked. Hmmmmm that's not right... Looking back (after I determined it was indeed working), the move was pretty stupid as I was hard on the brakes unweighting the rear end and the track was pretty cold so there was little grip to cause the slip, so the tire locked.

Talking to another dealer of Yoyodyne parts, I was told "if you don't feel it working, it's working. You won't notice it, you won't hear anything, it's working.". Then I thought... I'm flying into corners, going from topped out in 6th gear dropping down 4 gears as fast as I can fly through them with NO wheel hop or rear end waggle. In fact, the bike doesn't redline when I do this! Yes! Indeed!! It IS working...

The more I got used to it, the more I realized I could brake MUCH later. No longer do I have to worry about taking my time between downshifts. I can bang through them as quick as I can work the controls and it's all SMOOTH AND STABLE!

I never thought the slipper clutch would make as big a difference as it does, but I'm an absolute - sold - believer. This could quite possibly be the best race upgrade since suspension work. By far, this is my favorite gadget on the bike, and you can't even tell it's there.

Talking to some of my race friends who were watching me race, they commented on how obvious it was as I'd go through the downshifts in about 1/2 the time as those around me, and they would all be hopping around trying to stabilize the bike.

Without a doubt, the Yoyodyne slipper clutch goes into the "MUST HAVE" category for all racers.



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