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BMW Slipper Clutch

Unread postby OldButNotDead » Sun Sep 10, 2017 2:53 pm

I have a 2016 R1200GS LC. They come with a hydraulic slipper clutch. I've had numerous hydraulic clutches before but this is the first with a slipper clutch. I'm having issues when trying to feather the clutch. Let me start with a worst case scenario. I'm on a two lane road and come up on a 180 degree hairpin that climbs significantly. So significantly I have to go way left to start the turn, have it in first gear, but I have to slip the clutch to adjust speed through the turn. What I'm experiencing is while it is slipping rpm's go up then the clutch fully and rapidly engages and wants to pull the front wheel off the ground. I don't need to wheelie in that situation so I have to pull the clutch all the way in. It's a truly herky jerky affair and has you on the edge of dropping the bike. The best way I can describe it is the range of lever travel that translates from slipping (feathering) to fully engaged is extremely small. Any suggestions?
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Re: BMW Slipper Clutch

Unread postby Bob » Sun Sep 10, 2017 3:41 pm

Sounds like White Oak Mtn Rd. lol.

I read an early review of the LC bikes, I think it was in MCN, and they said exactly what you stated---the slipper clutch doesn't like the friction zone. It was bad enough for them to make note of it in the review. On both my 2015 GS and 2017 RT I do notice a little of this but find that revving the motor higher (much higher) than normal, while slipping the clutch more than normal seems to work better, probably because I'm sacrificing some clutch material each time I do this. It seems to tone down the jerky-ness you feel. Also, I'd make sure you run the exact spec oil recommended by der fodderland.
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Sun Sep 10, 2017 5:39 pm

Two things I have noticed is that it is much worse in Dyna mode and it got better when I adjusted the clutch lever to have the minimum amount of distance between the lever and the grip.

What really sucks about this problem is that it happens in really dangerous situations. I'm making an appointment for the fork recall and I'm going to ask the service manager some pointed questions about the issue. He is a good guy so I might actually find something out.
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Re: BMW Slipper Clutch

Unread postby Bob » Sun Sep 10, 2017 7:00 pm

OldButNotDead wrote:Two things I have noticed is that it is much worse in Dyna mode and it got better when I adjusted the clutch lever to have the minimum amount of distance between the lever and the grip.

What really sucks about this problem is that it happens in really dangerous situations. I'm making an appointment for the fork recall and I'm going to ask the service manager some pointed questions about the issue. He is a good guy so I might actually find something out.


Not sure how Dyna mode would figure in--maybe the throttle is a little snatchier in that mode---try RAIN mode next time in that situation to see if that helps. I used rain mode the first 4K miles or so until my wrist re-calibrated itself, since then only Dyna. (coming from a cable-throttle camhead)

Yep, I also found having the clutch lever as close to the grip as possible does help in modulating the the clutch action. In fact I'd like mine to be a little closer even. But do try "over-slipping" like I mentioned to see if that works, and let me know what your guy has to say.
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Mon Sep 11, 2017 8:33 am

As soon as the rain/wind event passes I am going to try that over-slipping. I have found that Dyna is snatchier in first but is fine everywhere else. Actually I'm not sure snatchier is the best description. The clutch just seems to fully engage much quicker.
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Re: BMW Slipper Clutch

Unread postby Bob » Mon Sep 11, 2017 8:54 am

One other clutch issue with the LC bikes---the engagement point is a moving target, not always consistent. This can figure in to what you describe. There have been times that I almost dropped the bike in a low speed hairpin because the clutch didn't start to engage at the point my hand thought it would (i.e. later) and by the time I corrected it I was already leaning too far and barely got the power back on in time. This doesn't happen often but I have become aware and am on alert when operating at low speed in corners.
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Mon Sep 11, 2017 11:36 am

Bob,
Yep, I know what you mean. You have to hunt for that engagement point and those climbing hairpins are NOT fun even if everything is exactly perfect.

The tinkerer is at work. <olfart> I've found a couple of guys who mention that the reservoir should NOT be at the fill mark. <bugeye> One even said there were a low and a high mark (not on mine). So I've done two things: one was to make the reservoir as near to level as is practical which changes the angle between the fingers and the lever; and reduced the level of the fluid. While doing this and making the lever set to position number one, I watched the engage point of the rear tire while it sat on the center stand. That gave me a much better look at how the clutch and lever were behaving together. Field testing will begin when I can see the sun again <toast>
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Re: BMW Slipper Clutch

Unread postby Bob » Mon Sep 11, 2017 7:10 pm

I saw your thread in ADV and went looking for that article I mentioned, couldn't find it but did spot this blurb from the adjacent link-->>

"My only complaint is that, when using the clutch, I found its very narrow friction zone at the end of the lever’s throw difficult to manipulate. Slow speed maneuvering was met with a herky-jerkiness I hadn’t mastered by the end of our ride."

http://www.motorcycle.com/manufacturer/ ... -ride.html

Article is about the RT but everything's the same.
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Mon Sep 11, 2017 10:23 pm

"they also have an unfortunate centrifugally energized
pressure plate design that creates control difficulties during hard
launches. Attempt a quick start on the new water-head, and its
clutch will bounce in and out of engagement, making the bike
hop instead of drive forward."
I found this in MCN when talking about the new R-Nine-T while talking about that model's dry clutch they referred to new wet head clutch issues. There is also a thread on AdvRider that talks to over filling the reservoir causing issues but it wasn't explicit on which issues. When I popped my res open a significant amount of fluid did come out. I did not refill and it is below the top mark, but I have yet to see the bottom mark some folks mention. My logic is it is "a RESERVOIR" and does not have to kept at full. If "full" causes problems a lower level won't hurt anything.
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Re: BMW Slipper Clutch

Unread postby Bob » Wed Sep 13, 2017 7:20 pm

I guess I should check my clutch level since its a new bike--that may be part of the issue. Also, I was reading that all 2017 LC motors have a judder damper added to the transmission output shaft (and a few other internal tranny improvements). Not sure if I really understand what was considered judder on previous LC bikes...but whatever it was/is mine is now DAMPED! <grin>

Edit: just checked my clutch reservoir, filled exactly to the top-line indicator which is well below "too full".
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Tue Sep 19, 2017 11:11 am

Isn't it amazing when you describe a problem, in this case "judder" and the service manager says "never heard of that before" along with the just about all the inmates on AdvRider, the 1200GS forum, MOA forum, etc, etc; AND THEN the elves in the Black Forest add a judder damper to the tranny. Hmmmm, something may be rotten in Bavaria. That same logic might apply to the res level. The documented cases all seem to be 2016 and prior LC models. Maybe conspiracy nuts aren't so crazy after all <grin>
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Re: BMW Slipper Clutch- Vindicated!!!

Unread postby OldButNotDead » Fri Sep 22, 2017 11:04 pm

A post from another forum:
Motorcycle Consumer News also spoke of the problem in an October, 2013 review of the R1200GS:
"The new 8-plate wet clutch is a big change. Unlike the automotive
style dry clutches used on previous boxers, the wet clutch
promised to be a big improvement as it should easily handle more
abuse without overheating in demanding off-road conditions.
And perhaps it could have been a purely positive experience,
except that BMW chose to fit a centrifugal pressure plate assist
to reduce lever effort and provide a back-torque limiting effect.
While its lever effort is commendably light, such a design also
changes engagement feel with rpm, becoming lightswitch sudden
at higher revs. Attempting jackrabbit starts from lower revs, the
clutch didn’t generate adequate grip, oddly grabbing and releasing
for a hopping launch that didn’t inspire admiration. From
high revs, its sudden action made wild wheelies too likely, so
conservative launches were the only way to go, and we didn’t
set any records as a result."

This description seems to be saying that the "centrifugal assist" and the slipper effect may in fact be due to the same mechanism. Still sounds like the only way to prevent a hopping launch is to have the clutch fully engaged before the rpm gets very high?
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Re: BMW Slipper Clutch

Unread postby Bob » Sat Sep 23, 2017 9:53 am

I think thats the original article I was referring to. FWIW my '17 RT doesn't seem to have this issue the way my '15GS had it.
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Re: BMW Slipper Clutch

Unread postby OldButNotDead » Sat Sep 23, 2017 11:54 am

You probably have the judder damper version that started on 2017 versions.
Just a FWIW, there have been lots more guys having this issue but didn't attribute it to the new clutch. I got a response on another forum where the guy just thought it was the traction control running amok. Never thought of that angle but it has some merit when you think about it. Maybe I'm brain dead, but have no clue when the traction control does anything or not <dope>
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