Author Topic: Clutch Issues on Cold Start  (Read 4966 times)

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Offline rcb78

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Re: Clutch Issues on Cold Start
Reply #20 on: May 04, 2021, 03:31:20 PM
Ok that makes more sense and you're right that it is the slipper/assist function that your feeling though it should be predictable.  I only feel it in my lever on downshifts and once the negative torque (engine braking) is removed or power is applied it returns to normal almost instantly.  When the engine is cold I can barely make out the assist function working but it's gone once the engine reaches operating temp.  FWIW this is on the replacement clutch that is from the 850gs, not the original one that lurched on cold starts.  That one felt like it had no slip/assist feature at all except when it was 'over' assisting when cold.
Is your clutch original and if so how new is your bike?

Offline PhilippeUSAG

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Re: Clutch Issues on Cold Start
Reply #21 on: May 04, 2021, 03:58:02 PM
*Originally Posted by patgm [+]
"Hung up" meaning, you're releasing the lever through its stroke, but the clutch mechanism seems to stop in a disengaged or partially-engaged position. You can feel this in the lever, as you'll have normal spring pressure against your fingers, but once it gets "hung up", it's as if the mechanism has become caught on something that the springs couldn't overcome, then as you release the lever more, the mechanism is able to overcome that resistance, and is suddenly engaged to wherever you currently have the lever. All of this happens in a fraction of a second. I wouldn't characterize it as slipping, once it is engaged, it is firmly engaged. it's definitely not shuttering, it is just failing to engage smoothly and controllably. I almost want to describe it as "notchy", but normally that's something that you would feel while both engaging and disengaging the clutch, and it wouldn't normally be intermittent.

If you were watching it happen while someone else was riding, you might think "that person hasn't quite figured out how to use the clutch yet." They would look like a new rider who has limited experience operating a manual transmission.

I saw something similar described on another motorcycle with a slip&assist clutch as well, I suspect that it has something to do with pressure on the assist ramps causing some uneven wear or some type of binding.

I've been trying to figure out a way to make it happen, since most of the time it is fine. These are things that I *think* might make it more likely to happen.  Though it is so intermittent that anything that seems like a pattern one day seems like superstition the next.
    Sitting for at least 48 hours, and being ridden gently/conservatively. The issue is definitely more likely at the start of the day, but I've experienced it at all operating temperatures, even when hot enough to have the fan running, and even after periods of extended riding.

    Cold/humid/wet weather; I noticed it a lot more frequently and more severely in February than I did in April.

    Coasting to a stop with the clutch disengaged at neighborhood speeds (i.e. 30mph, 3rd or 4th gear, pull the clutch in and progress down to first gear without engaging the clutch again until after you've made a complete stop).  This seems to precede this issue more frequently than if I were to downshift through all of the gears using either the clutch or the quick-shifter. I often do this within the neighborhood just to be polite to neighbors and pedestrians.

    Starting on an incline: it seems to happen more frequently when there is a bit more load to overcome from a stop.

    Bringing revs slightly above idle before engaging the clutch: if the revs are just slightly elevated, such as in a situation where you are on an incline stopped in dense traffic, then it is more likely to occur.  Notably, attempting a more aggressive launch with the revs far above idle is always smooth, I have not had this problem in spirited riding situations, it is almost always in traffic or neighborhood scenarios.

I hope that explanation makes it a bit more clear, I'm struggling to find the best way to describe the issue, and its infrequency is making it impossible to demonstrate to the service department as well.

Very good post!  I concur, same feeling here.
the gears are amazing in spirited riding with throttle open and revving 6-8,000.....then in traffic...clunky and exactly same feel as what oyu describe.
The way I found to mitigate it is by pulling the clutch handle only slightly (1inch?), shift gear, open throttle gradually smoothly, and release clutch... then it goes smooth.  If I pull the clutch handle all the way and then release, then it is likely to do the hangin stuff
If I release the clutch handle quickly....well, it doesn't jerk immediately...it hangs...then jerks...like if th ecable got caught for a sec.
Just weird.

Offline patgm

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Re: Clutch Issues on Cold Start
Reply #22 on: May 04, 2021, 05:35:34 PM
*Originally Posted by rcb78 [+]
Ok that makes more sense and you're right that it is the slipper/assist function that your feeling though it should be predictable.  I only feel it in my lever on downshifts and once the negative torque (engine braking) is removed or power is applied it returns to normal almost instantly.  When the engine is cold I can barely make out the assist function working but it's gone once the engine reaches operating temp.  FWIW this is on the replacement clutch that is from the 850gs, not the original one that lurched on cold starts.  That one felt like it had no slip/assist feature at all except when it was 'over' assisting when cold.
Is your clutch original and if so how new is your bike?

Mine is a 2021 F900R delivered to San Jose BMW in November 2020, currently at ~2700 miles, still on the original clutch. For the first 600 miles it was smooth, one of the best clutches I have ever experienced. After the first service (Performed by SJ BMW), I started noticing this issue, it became increasingly problematic over the course of ~3 months. Within the last 6 weeks or so, it has become slightly more mild and slightly less frequent. Until it was mentioned in this thread, I didn't know that the 850 clutch was now being installed from factory in the 900's, I thought the only 850 clutches were the ones that were replaced under warranty.

Offline Husky56

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Re: Clutch Issues on Cold Start
Reply #23 on: May 10, 2021, 03:10:31 PM
Man I thought it was just my sub par riding skills!   :008:  I'll have to take my bike in to get checked out.

Offline rcb78

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Re: Clutch Issues on Cold Start
Reply #24 on: May 10, 2021, 07:44:53 PM
*Originally Posted by patgm [+]
Mine is a 2021 F900R delivered to San Jose BMW in November 2020, currently at ~2700 miles, still on the original clutch. For the first 600 miles it was smooth, one of the best clutches I have ever experienced. After the first service (Performed by SJ BMW), I started noticing this issue, it became increasingly problematic over the course of ~3 months. Within the last 6 weeks or so, it has become slightly more mild and slightly less frequent. Until it was mentioned in this thread, I didn't know that the 850 clutch was now being installed from factory in the 900's, I thought the only 850 clutches were the ones that were replaced under warranty.

That's how mine was too.  It was trouble free (or so I thought) until around 2k miles, then it turned into an on/off switch on cold starts.  I will say this, I 'knew' the clutch was supposed to be a slipper but had never owned a bike with one before.  I just thought that it was underwhelming because I tried dumping the clutch on a few downshifts with the original and sure enough I backed it in.  Turns out that was the first sign of a problem as the slipper feature in the new clutch works very well.

Offline riderron

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Re: Clutch Issues on Cold Start
Reply #25 on: May 14, 2021, 03:12:51 PM
Hi, I posted on April 15 that I had an issue where the bike lunges forwarded after a cold start takeoff . I did take it up with the dealership and they found nothing wrong. Fast forward to yesterday it happened to me again May14-2021. This time I paid attention to what the circumstances that led me to believe that the bike was standing for approx. 8 hrs.' on the side stand and I started it in Neutral and this may be a wrong assumption, but I think because the oil drifts to the side away from the clutch on the side stand - this could cause the bike to lunge forward in its first movement. I usually start the bike when it is in first gear and the clutch is depressed this may circulate the oil better in the clutch area. Whoever is having issues with the clutch cold start, please try starting your bike while in gear and the clutch is depressed. Let me know in the comments.

Offline 10tenmen

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Re: Clutch Issues on Cold Start
Reply #26 on: May 14, 2021, 03:38:32 PM
Nothing to do with how you start it or how itís left for 8 hours, itís a diagnosed clutch fault and fortunately for me it happened to the mechanic when he test rode it the next day.
Mine went in on the 19th May and Iím hoping itís back by the middle of June. The BMW dealership have loaned me two brand new bikes 1st RS1250 then an R9T, now BMW UK have delivered a new 1250RT for the duration of the repair, the delay is a new sump pan.

Offline 10tenmen

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Re: Clutch Issues on Cold Start
Reply #27 on: May 14, 2021, 03:39:23 PM

Offline F9XRay

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Re: Clutch Issues on Cold Start
Reply #28 on: May 17, 2021, 04:35:23 PM
*Originally Posted by 10tenmen [+]


Now thats a great replacement vehicle for sure.
Shout out to your dealer.
~Don't surprise the front brake~

Offline Grumpyolgit

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Re: Clutch Issues on Cold Start
Reply #29 on: May 24, 2021, 01:48:28 PM
Hi all.Took my XR900 to dealer with clutch and neutral selection problems Told there wasnít a problem. Told them Iím not happy. Filled in a BMW customer device satisfaction E/mail not a good write up. 24hrs Later got a call from dealer to bring bike back on Saturday now Monday they phone and tell me they fitted a new clutch. I think great at first then because of there previous attitude. Iím thinking are they bull#####g. (Why?) because they stripped it this morning and out of the blue they just happen to have a spare clutch in stock. Think I will have to have a look at my old clutch or if not available Iíll ask to see the Job Card. Hopefully Iím wrong as Iv always had excellent service from them. Find out tomorrow.

 



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