STM Slipper Clutch Review

[Paul_E_D]

This winter I bought a used STM slipper for a reasonable price. After some long delays due to a missing washer, I finally installed it last week and spent monday and tuesday putting 260 track miles on it at Thompson Speedway.

After I put the thing back together with the old plates minus the anti-judder springs I took it around the neighborhood. Everything seemed perfect right out of the box with buttery smooth downshifts with zero modulation at the lever.

At Thompson I started cautiously as the only downshift point is coming down from 150MPH to about 40. After one lap though, I felt supremely confident and started pushing right away.

Every single downshift in about 130 laps over two days was absolutely perfect. I was able to brake later and harder with less stress than before STM. The bike rarely stepped out, and when it did it was so control-able that it was a non-issue.

For those who have never used one, there is still engine braking where you need it, but it is greatly reduced where you don't. Like magic.

I give this a 10 out of 10...so far.

[jwm2k3]

I'm in....

[Mr. Kurtz]

Does your STM have a provision to adjust the amount of slip? I'm curious because you mention "just enough" engine braking...and the Kawi with the Yoyodyne provides ZERO engine braking as it is set up.

[Paul_E_D]

The STM doesn't use the stock springs at all. It uses a big spring washer instead. They do sell different guage spring washers to adjust the amount of slip. When I say that there is still engine braking, I mean that it kicks back in as you lean the bike in to the corner, which to me is right where you want it.

Having ridden you bike, it does slip a bit longer than my STM, but not much. I loved that one too. I think yoyo uses stock springs? If so, you can adjust by getting heavier springs. or some combo of stock and heavy springs.

[xxaarraa]

Yes, I am a believer in the STM slipper also. Different models for different bikes of course, but I run one in my 848 with the stock plates and it is great. Install was a bit of a pain, the outer spider clip broke off in two places during install, but it's held up over many thousand miles of hard use. I bang out downshifts way early and bike is unfluttered. My new bike has a factory slipper and is noticeably not as good as the STM slipper.

[Paul_E_D]

That's funny, whoever owned mine before did the same thing breaking those little tines. Was it just not lined up? I don't even see how it happens.

[xxaarraa]

That's funny, whoever owned mine before did the same thing breaking those little tines. Was it just not lined up? I don't even see how it happens.

It's more to do with the clutch holder tool holding the hub down while you tighten. I have the motion pro tool that's made for dry clutches. You can use it on the 848, but you have to use it backwards (hard to explain - see photo) on a wet clutch. If the hub slips as you tighten, the spider clip is likely to pop. I am not looking forward to the day when I have to put new clutch plates in. I miss the dry clutch.

[Paul_E_D]

OK, I see. I used the holder tool on the outer part of the basket to torque the nut. There were a few spots where I could get it to bite enough.

[Tricky Mike]

A slipper was arguably the best upgrade on my 848.

[Kurlon]

A slipper was arguably the best upgrade on my 848.

So lets argue... I say, with no basis other than starting an argument that your paint job was.

[Ductard]

So lets argue... I say, with no basis other than starting an argument that your paint job was.

Since I bought his motard and he said he was selling it to buy parts for his 848, don't I have a basis to argue with him about what he's spending my money on? :-p

[kumpy]

wow, that sounds so awesome Paul!

[PainfullySlow]

I havent run the STM, only the Yoyo but I can say that I will never again own a track bike without one. They are THAT awesome.

Glad to see that you are enjoying the power, Paul! They really are amazing contraptions...