The Zephyr Zone

Hi all! I run into clutch problems yesterday and now I want to understand a bit more about this topic before open the engine. My bike clutch started slipping on hard acceleration. If I accelerate normally, then no problems but during hard acceleration it starts slipping around 4000-5000 rpm. Oil has been changed in May 1000 km ago, I use MOTUL 5100 4T 10W-40 ESTER. Leaver moves freely and has small gap so no tension there.

So I guess it can either be disks or the springs are starting to die. Bike has been driven 48 000 km. How long usually the clutch lasts? Anyone else had problems with that?

To inspect/change disks and springs, you don't need to 'open the engine'. It is one of the easiest things to do, however the 1100 has a hydraulically operated clutch, and this is also another system which may require some maintenance.

zep93 wrote:I use MOTUL 5100 4T 10W-40 ESTER.

Before you go pulling anything apart, dump the Motul out, and stick in a straight mineral (no such thing really, but trust you know what I mean) motorcycle oil. What have you got to loose other than the cost of 4? liters of relatively inexpensive oil.

Been down this exact same road, exact same oil with a 750.

I can only speak for a 750, but the friction plates do not wear much at all. I've had a few issues with slipping clutches on a 750, and the reasons were fully synthetic oils (especially Motul 5100), and springs loosing their tension. I have replaced friction plates, but when I measured the thickness of the old ones, there was next to no difference to the OEM replacements.

Thanks for the advise! As the season is already ended I will try this in the spring. Any recommendations for the oil that has not caused any problems?

zep93 wrote:Thanks for the advise! As the season is already ended I will try this in the spring. Any recommendations for the oil that has not caused any problems?

Just for the experiment use a straight motorcycle friendly mineral oil. Any oil, even if marketed as car oil, that states it meets the JASO-MA standard on the back of the bottle is fine. Oil sold as car oil is generally cheaper than the exact same thing stuck in a bottle with a motorcycle picture on the front. JASO-MA means 'suitable for use in a motorcycle with a wet clutch'.

If that works, then next oil change try a semi-synthetic. It's an Australian only oil brand, marketed at gas powers cars. That's as 'high tech' as I go with my 750 D1 (which has a stronger clutch than the C models) and I also have to use stronger than OEM clutch springs. Otherwise, full throttle at say 5000 rpm overtaking, and just watch the tacho spin up to 9000 with no increase in speed.

I am afraid it is just more than oil. I drove yesterday to my winter garage and noticed vibration when releasing clutch on starting to move every time. And it was starting to slip even easily than las time.

I will take it apart next spring.

So after opening clutch assembly it turned out that the plates were worn out and I changed all the plates and springs. Now clutch is operating perfectly and I am happy with the result!

Sorry for bumping these old posts but thumbs up to guys for contributing to the threads. There aren't always enough Zephyr contributors around to get a quick answer

Changing the clutch plates on the 750 takes about 30mins - if you have the right tool.
On my BMW dry clutch takes days to change and requires the removal of practically everything.