clutch take up point and clutch Life

[kennykeg]

Hi Everyone
I'm trying to work out if my clutch is near the end of its life or if it is common for the clutch on an St1100 to fully drive only in the last few millimetres when letting the clutch lever out.
I have owned her for just over two years and the clutch action has always been the same but when accelerating hard uphill onto the F3 the other day I had the slightest impression the clutch slipped a bit extra  during a change from 3rd to 4th. She is a 2001 model ex police bike. I'm running Penrite MC-4st 10w-50 semi synthetic oil and she has 75000 on the clock.
Any insights into clutch behaviour would be greatly appreciated
 

[Biggles]

The ST1100 clutch commonly only engages in the last couple of centimetres of travel.  The sense the clutch slipped a bit might have been because you brought the revs up a bit too quickly on the up-change.  Replacing clutches on these bikes is virtually unheard of. 
The "clutch issue" that is most commonly discussed is the noise they make if you hammer them when they're cold, e.g. a high powered acceleration with high revving gear change.  It's a rather disturbing noise associated with the basket structure, and again, something owners live with rather than fork out $800 to fix.
Saaz will be here shortly with further insights.  (He's our resident 1100 guru    )

[Pezzz]

+1 for me as well.. Eagerly awaiting Saaz as I have similar experience with "clutch slip" in 5th just rolling on throttle to overtake from around 90 on highway. Old bike would just rattle and then proceed. The ST1100 seems like winding up rubber band and then all engages and wham... Off you go....

Mine has only done 52000 km.

[alans1100]

I can't say I've had that issue as mine is quite happy in 5th gear at anything above 80/90 for overtaking but down to 4th for a B double and larger.

As for clutch travel on mine the clutch is disengaged within the first 1/3 of the clutch lever travel.
 

[saaz]

The clutch takeup on the ST11 is a narrow band near the end of the lever travel. I fitted an adjustable clutch lever as it was a bit too far out for me when it had to be used a bit in town.  I have the original clutch in mine at 210,000kms and it works fine.  It does sometime make that 'clacky' sound when taking off, more when cold but it can be when hot. It might not do it for months.  Because of the narrow band it is easy to not match up revs with gear changes so it might seem like slipping

The clutch should not slip in top gear roll ons.  Some ex police bikes used for escort duty can get a hard time as the clutch is ridden hard for slow speed work.  STroppy has one that he thought might need changing, he bought the plates, but at 140,000kms has not gotten around to fitting them.  Bleeding the clutch slave cylinder is a start, as it can gum up, but most times it leads to the clutch not disengaging.  Sticking to a known oil that is rated for wet clutches if you suspect a problem is another key factor.  If the wrong oil has been used in the past it might take a few changes to get rid of the wrounf oil from the clutch plates.

After all that, it is possible that the clutch is slipping - but it does take big mileages and abuse.

[kennykeg]

Thanks everyone for your replies

I feel a lot more confident now that it is an ST trait and not a failing clutch.

 

[Pezzz]

Thanks saaz.... I know there are threads and threads on oil but what signifies one for a wet clutch?

Sent from my GT-I9100 using Tapatalk 4

[Brock]

Any oil with PTFE or other "Friction modifiers" are no good, as the clutch plates need friction to work..

[saaz]

As Brock says, any oil that mentions friction modified for fuel economy is not good.  Usually oils like 10W-30, 5W-30 and lower should be avoided, unless the oils says it meets JASO MA or MA2 standard for wet clutches.  For example, Honda sells a 10W-30 oil for bikes.

Most of the oils for diesels are good as they have extra anti wear and anti shear additives compared to normal car oils, are readily available and relatively cheap compared to over priced bike oils.  Penrite also make a number of oils that have the MA rating, including bike specific oils.  The ST11 and ST13 are easy on oils so any decent quality oil will do fine.

[Brock]

A good guide to what works for your bike, is that if the gear changes start to get clunky and harder to do after a few thousand Ks, then the oil isnt right for you. Currently, I'm using Penrite HPR 20W-60 extra ten Diesel. Its been in there about 6000Ks so far.