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#765812 - 03/14/12 05:18 PM General question about clutch fethering
cpayne Offline
Member

Registered: 02/08/12
Posts: 145
Loc: RIchmond, VA
Just finished MSF basic class at Fort Lee, so I can ride on base.
e used Susuki 250. Big difference from 1150. During the entire class we were abusing the clutch and brakes. Never smelled clutch on any of them. I sometimes smell a little on my bike after a ride with very little feathering taking place.
I asked the instructor if this was normal. He said he has been teaching for years and has never had a clutch go out on him. only changed front pads.
He did mention that in the advanced riders course a guy with a big cruiser burned his out after 10 minutes of doing what we did for two days. I assume something was wrong with his clutch from the get go.

What are your experiences with BMW bikes as feathering (control) is a major technique in Motorcycle riding.

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#765822 - 03/14/12 05:38 PM Re: General question about clutch fethering [Re: cpayne]
Penforhire Offline
Member

Registered: 10/18/08
Posts: 465
Loc: La Habra, CA
I use more care with dry single plate clutches (such as my RT's) than with wet multiplates. It will not stand up to as much abuse. It doesn't mean I don't feather it for control but more often I'm conscious to lock it up sooner and slip it less than I did with wet clutches.

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#765826 - 03/14/12 06:00 PM Re: General question about clutch fethering [Re: cpayne]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8489
Loc: Ohio
Evening cpayne

The clutch on your bike is what's known as a dry clutch. That means it is not oil cooled & doesn't run in oil.

The clutch on your motorcycle is a rather large clutch disk (about the size of a VW beetle) so you can feather it a bit at low engine RPM's if needed. High RPM slippage will kill your clutch in a hurry though as that make tremendous heat.

You really do need to be a bit careful with it as you can fry it if you slip it very long with raised engine RPM's.

If you are smelling the clutch after usage you are probably using a bit too much feathering at too high of an engine RPM during the feathering.

If you know what you are doing the BMW dry clutch can be slipped or feathered a fair amount without damage but on the BMW dry clutch there is a very fine line between light feathering & destructive slipping.

On my BMW GS I abuse the heck out of that clutch when off-roading in deep sand or real tight narrow trails but never at raised engine RPM (that means high engine torque) & not for long. Haven't fried a clutch yet.

I don't use a long term high rev feathering though-- it is more of a low engine RPM thing while pulsing of the clutch lever (continuously pulling the clutch lever slightly in & out at the engagement point).
_________________________
D.R. ___
Sent from my rotory dial wall phone!

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#765867 - 03/14/12 08:21 PM Re: General question about clutch feathering [Re: dirtrider]
cpayne Offline
Member

Registered: 02/08/12
Posts: 145
Loc: RIchmond, VA
Thanks for the detailed information. This explains quite a bit. I haven't had the bike very long and I didn't know the difference. I may have been a little aggressive the first couple of times i rode the bike. Hence the smell.
I went for long(to me) rides yesterday and today and feathered quite a bit in and around intersections lights etc... No smells of clutch!

Seems that wet may be more reliable or durable? If so why would manufacturers use dry clutches?

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#765874 - 03/14/12 08:40 PM Re: General question about clutch feathering [Re: cpayne]
bgf50 Offline
Member

Registered: 08/23/05
Posts: 172
Loc: State College, PA.
I've only smelled my clutch burning twice. Once when I was starting out on a steep hill with my wife on the back ( I almost always ride solo) and once when I was riding with my brother. He has a LOUD cruiser and when I was behind him I couldn't hear my bike at all and I revved the engine too much. I really wasn't even sure my bike hadn't stalled because his bike was so loud.

Bill
2012 RT
09 KLR

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#765920 - 03/15/12 12:03 AM Re: General question about clutch feathering [Re: cpayne]
Rex R Offline
Member

Registered: 07/14/10
Posts: 188
This issue has been covered several times on this forum (and others.) You can search for related threads if you would like to find more info and other opinions.

The info I'm posting below is a cut-and-paste from a brochure for the 1200RTP. It backs up what Dirt and other posters say and further explains why you have to keep the revs low in the grey zone and why you might not need to slip the clutch at all during maneuvers that would require other bikes to stay in the friction zone.


Whats Up With BMWs Clutch?
BMW utilizes a different clutch system than some of our competitors. BMWs clutch is a hydraulic (self-adjusting) single-plate dry clutch as used in cars and trucks well proven for long life. Our competitors utilize a multi-plate wet clutch, which runs in an oil bath.
The primary difference between the two designs is that the dry clutch operates at the end of the engine crankshaft before the primary gear reduction. The wet clutch design operates after the primary gear reduction. Meaning, that for a given RPM on a dry clutch design, the same RPM on a wet clutch design will be turning that wet clutch surface approximately half as fast (feet-per-second at the plate surface). Conversely, if you have been trained to ride a wet clutch motor, you will need to greatly reduce the RPM on the dry clutch motor to keep from over-heating it. How long would any wet clutch last if you grey-area slipped that clutch at 5,000 rpm?
Furthermore, the unique BMW opposed-twin engine design enables the motor to pull itself at idle with no throttle in either first or second gear. Consequently, the motor works best at slow rpm grey area operation below 2,000 rpm. Most fleets that have received indoctrination training have experienced no clutch issues and are seeing clutch life as high as 60,000 miles! Lastly, the BMW warranty covers the clutch for wear in the first 12 months while your officers acclimate to the motor!





CHPs (who are the biggest user and therefore the most experienced with these bikes in this country) train their cops to perform slow speed maneuvers without the use of the rear brake (using only clutch, throttle control and perhaps counter-balancing ) The reason being dragging the rear brake, although it tends to stabilize the bike and makes it easier to ride the training/cone courses, also forces you to raise the revs putting more wear on the clutch and input spline shaft.

Good luck with your new wheels, and thank you for your service.

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#765967 - 03/15/12 08:50 AM Re: General question about clutch feathering [Re: Rex R]
cpayne Offline
Member

Registered: 02/08/12
Posts: 145
Loc: RIchmond, VA
Originally Posted By: Rex R
This issue has been covered several times on this forum (and others.) You can search for related threads if you would like to find more info and other opinions.

The info I'm posting below is a cut-and-paste from a brochure for the 1200RTP. It backs up what Dirt and other posters say and further explains why you have to keep the revs low in the grey zone and why you might not need to slip the clutch at all during maneuvers that would require other bikes to stay in the friction zone.


Whats Up With BMWs Clutch?
BMW utilizes a different clutch system than some of our competitors. BMWs clutch is a hydraulic (self-adjusting) single-plate dry clutch as used in cars and trucks well proven for long life. Our competitors utilize a multi-plate wet clutch, which runs in an oil bath.
The primary difference between the two designs is that the dry clutch operates at the end of the engine crankshaft before the primary gear reduction. The wet clutch design operates after the primary gear reduction. Meaning, that for a given RPM on a dry clutch design, the same RPM on a wet clutch design will be turning that wet clutch surface approximately half as fast (feet-per-second at the plate surface). Conversely, if you have been trained to ride a wet clutch motor, you will need to greatly reduce the RPM on the dry clutch motor to keep from over-heating it. How long would any wet clutch last if you grey-area slipped that clutch at 5,000 rpm?
Furthermore, the unique BMW opposed-twin engine design enables the motor to pull itself at idle with no throttle in either first or second gear. Consequently, the motor works best at slow rpm grey area operation below 2,000 rpm. Most fleets that have received indoctrination training have experienced no clutch issues and are seeing clutch life as high as 60,000 miles! Lastly, the BMW warranty covers the clutch for wear in the first 12 months while your officers acclimate to the motor!





CHPs (who are the biggest user and therefore the most experienced with these bikes in this country) train their cops to perform slow speed maneuvers without the use of the rear brake (using only clutch, throttle control and perhaps counter-balancing ) The reason being dragging the rear brake, although it tends to stabilize the bike and makes it easier to ride the training/cone courses, also forces you to raise the revs putting more wear on the clutch and input spline shaft.

Good luck with your new wheels, and thank you for your service.

More great information. Thanks and I'll try to find some of the posts you mentioned.

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#766088 - 03/15/12 07:06 PM Re: General question about clutch fethering [Re: cpayne]
lkchris Offline
Member

Registered: 11/19/02
Posts: 803
Loc: NM USA
Boy, does this miss the point.

The real point is that driving around a parking lot has so very little to do with motorcycling in the real world and is of course the fatal flaw with MSF.

Granted "political correctness" dictates that MSF isn't going to be able to get state funding to give you race track experience, but that remains indeed the best sort of motorcycle training.

Now that you're past MSF, clutch feathering is irrelevant for the most part. You can start shutting your motor off with the ignition key, too.
_________________________
Kent Christensen
Albuquerque
'12 R1200RT, '02 R1100S, '84 R80G/S

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#766098 - 03/15/12 08:07 PM Re: General question about clutch fethering [Re: lkchris]
Huzband Offline
Member

Registered: 06/02/06
Posts: 7415
Loc: Cowford, Fl.
That is so wrong on so many points, I hardly know where to begin. But I'll try.

1; Parking lots are a great place to work on the basics, ie, accelerating, shifting, clutch work, basic manuvering...

2: Track days don't teach beginners how to ride, they teach riders how to ride better.

3: Clutch feathering...ever try to turn a moto around in a tight space, or negotiate a tight corner, without paddling like a duck?

lkchris, I think YOU miss the point.
_________________________
Danny

'07 R12GSA (Moose)
'04 Sherco 2.9 (Sherpa)
'97 KTM 400 R/XCe
'90 RMX 250 (woods weapon)
'08 Black Lab (Auto)
IBA #30344


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#766099 - 03/15/12 08:09 PM Re: General question about clutch fethering [Re: lkchris]
David13 Offline
Member

Registered: 02/20/09
Posts: 1911
Loc: Los Angeles, CA USA (Lomita)
Kent
I don't think I'm being politically correct by saying I disagree.
Anyone can make the motorcycle go fast. What takes skill, and most importantly control, is to make it go slow.
I do agree. Shut the bike off with the ignition key.
dc

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