Why won't BMW make a decent gearbox ?

[Engineer]

I'd still l like to know what BMW mean by 'self energising' clutch on the LC and the details of how it works - I am sure that there is a clue in the design somewhere that will explain the compromise between the very light action and the little bit of drag.

Is there anyone who really knows how this particular clutch works or can point me to a link that explains it in proper engineering detail?

 

[cookie]

I'd still l like to know what BMW mean by 'self energising' clutch on the LC and the details of how it works - I am sure that there is a clue in the design somewhere that will explain the compromise between the very light action and the little bit of drag.

Is there anyone who really knows how this particular clutch works or can point me to a link that explains it in proper engineering detail?

isn't it just a slipper clutch that clamps itself down with the force of rotation?

you know, like KTM use.

 

[alp]

I'm also curious like yourself about the details of this clutch. I've never seen one in pieces or have access to an exploded parts diagram.
In my mind I picture a GS LC clutch which has some (maybe not all) of the features of the latest Ducati wet clutch, e.g Multistrada, Diavel and others. The Ducati clutch has a lighter clutch lever action by way of the clutch's design which tightens up the clamp between the plates when under power load, thereby surviving with lower spring clutch rates than would otherwise be needed. Could this be what BMW calls self-energising?
The Ducati clutch also releases some of the plate clamping force to allow clutch slip when reverse loaded by banging the gears down too early/soon relative to engine speed/gear/road speed which would otherwise cause the rear tyre to lock, which is useful on big twins which have typically higher reverse torque resistance than fours.
While the GS LC clutch may have some similarity to the Ducati clutch, my Ducati with this design didn't show the same traits as the GS, so the detail design is going to be different in the way the design engineers tried to accomplish the result they wanted.
Post up if you find details of the GS clutch.
Cheers.
P.S. My '13 GS LC clutch also experienced an occasional spurious variation in lever biting point causing a kangaroo pull away which would catch me by surprise. This confused me as something unique in my experience so there is something equally unique about this clutch. Keep digging!

 

[DING-DONG]

Is there anyone who really knows how this particular clutch works or can point me to a link that explains it in proper engineering detail?

Why not ask BMW top technical bod !

[email protected]

(The email is a guess, but seems everyone whom works there has a personal email address, that starts first name . Surname)

 

[Giles]

I genuinely feel so sorry for the guys that have invested thousands into a dream bike and are now so disappointed. What's gutting is that once you get a serious niggle, that little doubt in the back of your mind ... it just ruins the love affair.

Alan - Hope yer well (I can't pm you ..) I have a KTM 1190R now . Ill be going to Corsica with P & G in September ...

 

[Engineer]

I'm also curious like yourself about the details of this clutch. I've never seen one in pieces or have access to an exploded parts diagram.
In my mind I picture a GS LC clutch which has some (maybe not all) of the features of the latest Ducati wet clutch, e.g Multistrada, Diavel and others. The Ducati clutch has a lighter clutch lever action by way of the clutch's design which tightens up the clamp between the plates when under power load, thereby surviving with lower spring clutch rates than would otherwise be needed. Could this be what BMW calls self-energising?
The Ducati clutch also releases some of the plate clamping force to allow clutch slip when reverse loaded by banging the gears down too early/soon relative to engine speed/gear/road speed which would otherwise cause the rear tyre to lock, which is useful on big twins which have typically higher reverse torque resistance than fours.
While the GS LC clutch may have some similarity to the Ducati clutch, my Ducati with this design didn't show the same traits as the GS, so the detail design is going to be different in the way the design engineers tried to accomplish the result they wanted.
Post up if you find details of the GS clutch.
Cheers.
P.S. My '13 GS LC clutch also experienced an occasional spurious variation in lever biting point causing a kangaroo pull away which would catch me by surprise. This confused me as something unique in my experience so there is something equally unique about this clutch. Keep digging!

This is my understanding of how it works in general terms too, it is curious that the bite point on my 13 GS LC has in almost 22,000 miles never shown any varying bite point issues.

One thing I do notice with the clutch though is that when I engage 1st gear with the engine off and then paddle the bike forwards and backwards is that the clutch drag varies - I can feel it trying to turn the engine and feel the difference as the crank rotates the piston through its travel BUT sometimes there is a 'clear' spot and if I start the engine at this point there is no 'lurch' whatsover. Also if the bike is really, really stone cold (less than a few degrees C) then it always goes into first (with the engine running) with no clonk at all.

I really would like to know how this clutch works.

 

[Engineer]

Why not ask BMW top technical bod !

[email protected]

(The email is a guess, but seems everyone whom works there has a personal email address, that starts first name . Surname)

I will email him but I suspect that they won't give me the design details, I'll let you know what his reply is.

 

[Engineer]

isn't it just a slipper clutch that clamps itself down with the force of rotation?

you know, like KTM use.

I guess so but I want pictures and an explanation of how the BMW one works

 

[Matty589]

I noticed recently, as someone with a GS with 8,000 miles now and can never find neutral up from 1st (but can most of the time down from 2nd) that if I pull the clutch right in as far as it can go I can always find neutral no matter what. Something to do with clutch adjustment maybe but the bite point is exactly the same every time and in the right place.

 

[alp]

Alan - Hope yer well (I can't pm you ..) I have a KTM 1190R now . Ill be going to Corsica with P & G in September ...

Yep, all well here and still a BMW enthusiast, I've been to the BMW Fest at Garmisch for the last 2 years. I rented a F800GT for the 2014 though.
Brave man going to Corsica again, hope you don't end up in that hotel in the sticks again! If so, ask Peter to tell the chef to properly cook the salmon next time.
Cheers mate.

 

[peterh]

I guess so but I want pictures and an explanation of how the BMW one works

I believe (might be wrong) that the principle behind the GS LC clutch is the same as that on the K1600. A copy of a BMW description and diagram of that clutch is at post #3 here http://www.k1600forum.com/forum/bmw-k1600-general-discussions/48426-clutch-plate-clunk.html

 

[alp]

Thanks for the info Pete.
It seems we have the principles guessed right if we can assume design similarity with the 1600.
I'm not too clear about the 1.6mm stated as the release distance since the release distance will vary with the clutch lever setting i.e. lever set furthest out or in.
A reduction in the 30mm diameter of the slave cylinder would increase the clutch release e.g 26.5mm diameter would give 2mm release. This seems such a simple change to make that surely they have tried this? Maybe not.
It's interesting that BMW have stated that '...when this (self energising) is active, it may cause slight movements in the clutch lever'. My occasional problem with changing lever bite point seems to be related to this.
Cheers.

 

[yankeedoodledandy]

I noticed recently, as someone with a GS with 8,000 miles now and can never find neutral up from 1st (but can most of the time down from 2nd) that if I pull the clutch right in as far as it can go I can always find neutral no matter what. Something to do with clutch adjustment maybe but the bite point is exactly the same every time and in the right place.

If your lever adjustment is already on 4 and it is not disengaging enough to find neutral, you can also adjust the master cylinder plunger using a small (2 or 3 mm, can't remember which) allen wrench. Loose the cross (locking) screw and then screw the plunger in or out to adjust as needed, then tighten the locking screw again.

 

[alp]

If your lever adjustment is already on 4 and it is not disengaging enough to find neutral, you can also adjust the master cylinder plunger using a small (2 or 3 mm, can't remember which) allen wrench. Loose the cross (locking) screw and then screw the plunger in or out to adjust as needed, then tighten the locking screw again.

Hey Matty589 any chance you can try this? My GS has long gone.
If it works then maybe, just maybe, this is why some experience neutral finding problematical and others don't, if the adjustment varies from the factory?

 

[Voz]

2015 GS with 1800 klm, GSAP, gearbox and clutch are like silk, completely different and much better than my 13 GSW.

 

[GrinningGSer]

If your lever adjustment is already on 4 and it is not disengaging enough to find neutral, you can also adjust the master cylinder plunger using a small (2 or 3 mm, can't remember which) allen wrench. Loose the cross (locking) screw and then screw the plunger in or out to adjust as needed, then tighten the locking screw again.

Where is the master cylinder plunger because I thought it was somewhere behind the front cover ?

 

[mcinlb]

If your lever adjustment is already on 4 and it is not disengaging enough to find neutral, you can also adjust the master cylinder plunger using a small (2 or 3 mm, can't remember which) allen wrench. Loose the cross (locking) screw and then screw the plunger in or out to adjust as needed, then tighten the locking screw again.

This may be some good info, but a couple of pics would help greatly

 

[Titto]

I wonder if this is a major factor in why so many of us have different results, if the adjustment is different at the factory then its got to be looked at. Pics please!

 

[alp]

Where is the master cylinder plunger because I thought it was somewhere behind the front cover ?

The master cylinder is actuated by the clutch lever and is therefore on the left bar. The slave cylinder which pushes the push rod which passes through the engine to the clutch release plate is at the back of the engine casings.

 

[Mozz]

Come on then pics please