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Clutch Slipping


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Hi All,


I was hoping I could get some combined wisdom from the people on the board.


I have one of the last R1150T manufactured with 28,000 km on it, as I was riding yesterday with my wife on the back I noticed the clutch slipping in 6th gear on the highway.


I did a search yesterday and today on the board, and from what I can make out the most likely cause is a seal gone in the transmission causing oil to get on the clutch plate.


Would appreciate if others think this is the diagnosis.


If this is the case and I have to split the bike to repair the seal, what clutch components will need to be replaced considering the mileage of the bike ?


Would also appreciate if anyone else has inputs as to other possible reasons for the problem.






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There are two possible seal failures here - the transmisison input and the crankshaft rear seal. The other possibility is that the clutch is plain worn out. These dry clutches can wear very rapidly if the bike is slowed using down-changes rather than the brakes.


Check the clutch fluid level, if this is at the top of the window, try taking a little out - the correct level with a new clutch is the bottom moulded step in the resevoir - the fluid level rises with clutch wear and if over-filled this can prevent the clutch from fully engaging when the lever is released.


If the level was high and draining fluid did not help, then you are into the bike to discover why.


Personaly, I would by a clutch 'pack' for simple reason that it is a BIG job getting to the clutch, although in theory if the problem is seal related, a new plate and degrease of the cover and pressure plates is all that is required.



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28,000 km seems too soon for the clutch to have worn out, unless horribly misused. I like Andy's idea of checking the level in the clutch fluid reservoir.


So few km on a bike this old suggest that it may have been left sitting for long periods without being ridden, which can lead to seals drying out. Unfortunately, if the clutch disk is contaminated, you are in for a major effort to resolve the problem.


Also check the fork tubes for signs of leakage. If the tubes are oily, and there is no evidence of rust or damage to the fork tubes, leaking fork seals are fixable just by adding some ATF seal conditioner to the fork oil, without bothering with disassembling and replacing the seals. The only "special" tool needed is a 22mm spanner to prevent the tube from turning when you remove the top nut, and a syringe with a long hose to suck out the old fork oil. For my first oil replacement, I drained from the bottom; the second time, I sucked the old oil out, and was amazed at how much "crap" came out from the same tube.

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Thanks Andy,


When I got home from work I checked the fluid level and it was at top of the sight glass, no space visible at all.

When I took off the fluid reservoir cap and took out the diaphragm, the diaphragm was actually pushed inwards. So i guess it really was overfull.


I have noticed in the last 2,000 km that the clutch lever was engaging at the very end of the lever travel.


I removed some fluid to bring the level to just below mid point on the sight glass and reinstalled the diaphragm and cap.


As it is late here I have not had chance to give the bike a run, but the clutch lever now bites at an earlier stage of the levers travel.


I find this board invaluable for assistance with the bike, living in the Philippines it is not easy to get expert help. This board and the people who use it are a great resource to someone like myself.


I will give the bike a good run at the weekend and update on the situation.


Once again thanks.




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There are two possible seal failures here - the transmisison input and the crankshaft rear seal.

On the R1150xx there is a third possibility – the input shaft rear seal and subsequent migration of the transmission lube up the clutch push rod and onto the clutch disk.

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Hello very interesting about the clutch fluid level, will have to check mine!


My clutch has never been the same having done two slow riding Dexterity & Control courses on very hot days, with the lack of cool air flowing through the oil cooler everything got too hot. Could be these were expensive lessons unless removing fluid resolves the issue. :cry:

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My '04 had the rear trans seal go bad at 14k miles. I noticed a "hot oil" smell as I would be stopped at a stop light for several weeks prior to the failure. The smell came from the transmission oil getting hot from the clutch disc. It was already slipping, just not enough to feel it and building a little heat. After taking the RT apart and repairing the seal ( you do NOT have to split the transmission to replace the rear seal) I replace the clutch disc and all has been well since.


I would be tempted to try an in bike repair. I believe it may be possible to remove the seal with the transmission in place and then replace it. Next you would have to clean the clutch disc. I would be willing to try removing the starter and with the clutch released spray brake cleaner on it while rotaing back wheel. You might have to vacuum out the spent brake cleaner but most would evaporate.

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