Dr. Pulley Clutch Life

[davidh]

Anyone have experience with the life expectancy of the friction material on Dr. Pulley clutches? Here's what I have:

-- 2013 BMW C650 GT
-- 55,000 miles
-- Dr. Pulley HIT Clutch 302002 V4
-- Stock clutch bell
-- New belt and sliders (30G)

I replaced the BMW clutch at 40k miles and have been happy with the response. Starting last week, however, it was REALLY sluggish off the line but had good response above 15-20 MPH. I'd seen some wear on the leading edge of the clutch material last time when I replaced the belt late last fall and checked with Michael at Buggy Parts (always SUPER helpful!) and he advised the following:

Leading edge clutch wear is completely normal, as that is the part that most often comes in contact with the clutch bell. The shoes pivot out from one end, and the far end is always going to be the first thing to touch and get worn more. The good news is that as that front edge gets worn down, more of the rest of the pad will then come in contact with the clutch bell. You only need to worry when that leading edge of the clutch pad is completely gone or less than 1mm thick.

Seeing that I had enough material on the leading edge (closest to the pivot point) I put everything back together and got back on the road. Taking it apart today, however, discovered that the base metal now been contacting the clutch bell (likely explaining my poor off-the-line response) at the trailing edge (furthest from the pivot point) and I'm not sure what should be my next step. The clutch has only 15k miles on it and is significantly more worn than the OEM clutch with 2.5x the mileage (see pictures).

I'll be eMailing Michael to see if Dr. Pulley has re-engineered their friction material but I can't see replacing them ever 15k miles -- it's a big pain in the butt and I'm not sure the increased performance is really worth the effort.

Thoughts?

 

[TwoPort]

- Was my next planned purchase now that I got lights. But this is the first I've heard about Dr. P issues.

 

[RollaCosta]

I have had about 60000 km on mine now and the pads are fine, hardly any wear. Also no issues on the bell.
The issues were mostly spring tuning, and one more thing...
With springs, they ship with Yellow 11Kg pillow springs, those are fine.
However, the clutch springs are too tight (I think they are 10Kg) and they engage at significantly higher rpms.
Causing two issues :
1) when trying to crawl in a traffic jam, your engine ROARS and then moves maybe 3ft forward, shuts up. Repeat. Silly!
2) when riding technical and tight mountain twists, in a corner you set throttle to zero and brake, but then transmission goes to "Neutral" because it disengages at high rpms (tight clutch springs) and you get this 'icky feeling' without ending braking and then on corner exit you add throttle and it "jerks" with re-engaging transmission. Very bad for confidence.
So what have I done to resolve both issues?
I have found blue 6.5Kg clutch springs - they came with HiT clutch for my Aprilia SRV 850.
The model name is SP1532407095-BL 6.5Kgand they are perfect! You probably have to ask Dr. Pulley to supply those.
Please note that previously I had used even weaker (the weakest from Dr. Pulley) 5.2Kg springs but what happened after 20000km is they have stretched and the clutch started to engage too early, causing judder and ATC reaction at the very start and some vibrations on the go.
The 6.5Kg seems perfect for now, will see what happens after 10-20K kms...
The other issue with HiT clutch is that there are "spring dampers" mounted inside the moving metal pads, perpendicular to the base plate (coaxial with the shaft they rotate around). These are for quieting the pads so they rattle less.
Well, the issue is that on the other side of the shoes there are two "support pins" that the damper springs on the other side press against. They wear. They also scratch "channels" in the 2mm base plate, and shoes may catch there at certain rpms.
This is probably the last and quite minor issue (causes rattle at idle).
We have tried to smoothen the scratched base surface with a light Dremel but there is only so far you can go on a 2mm thick plate.
So some rattle remains, after 60000 km run and many spring experiments.
Compared to original clutch, there never was "floating torque" at high speeds, but I would really prefer if Dr Pulley's have shipped HiT 30202 with BL-6.5Kg clutch springs so I have not wasted time and effort on the tuning experiments.
And finally, why do they NOT make a torque spring washer for the C650s?