So how do I know it's not the driveshaft?

[The Grey One]

I have been checking through old threads about clutch failure and come across mention of drive shafts failing and giving the same symptoms.

My 1150 developed what feels like clutch slip, it came on quickly, one day OK the next it "slipped" under load at high revs. Bike has done 33,000 miles. I took it out again and at first it appeared OK but within a few miles it was slipping again.

I have removed the starter to check for oil/fluid on the clutch and today I dismantled the final drive to check for rubber in the housing as mentioned in the posts about drive shaft failures. No sign of anything so does that mean the shaft is OK? Is there any way to check it when I get the thing apart to look at the clutch?

John-very pissed off at the moment-fantastic biking weather here and with the season winding down I could be out there most days!

 

[JayC]

Just curious , before the partial strip down did you try having the bike stationary (whilst sat astride), start the motor, select a lower gear, apply brakes firmly , and gently feed out the clutch to see if the bike stalls or not.

 

[The Grey One]

Just curious , before the partial strip down did you try having the bike stationary (whilst sat astride), start the motor, select a lower gear, apply brakes firmly , and gently feed out the clutch to see if the bike stalls or not.

Yes tried that, it stalls. I only noticed the slipping when gunning it and then only at high revs. it was OK last Saturday when I was let of the lead
on the Nockalmstrasse

John

 

[JayC]

Yes tried that, it stalls. I only noticed the slipping when gunning it and then only at high revs. it was OK last Saturday when I was let of the lead
on the Nockalmstrasse

John

Well that does surprise me! The static test with brakes applied would put the clutch under a far greater loading than a high rev session and yet it stalled. So, on that basis I'm out...unless you failed to feed some decent revs in whilst stationary?

 

[Hugh Jardon]

I'm not an expert but mine did the same - seemed to work ok then after a few miles slipped, stop and let things cool down and it would be ok again for a few miles.

Other thing that was similar was the slip at high revs a while before it went pear shaped.

In my case, I replaced the clutch to no avail then had to do the drive shaft the next weekend.

One clue could be crumbs of black rubber inside the drive shaft housing (I saw them but didn't realise the significance) - you have to strip it down in either case

 

[The Grey One]

I'm not an expert but mine did the same - seemed to work ok then after a few miles slipped, stop and let things cool down and it would be ok again for a few miles.

Other thing that was similar was the slip at high revs a while before it went pear shaped.

In my case, I replaced the clutch to no avail then had to do the drive shaft the next weekend.

One clue could be crumbs of black rubber inside the drive shaft housing (I saw them but didn't realise the significance) - you have to strip it down in either case

I can't see any rubber but as it failed to stall when I held it on the brakes i still suspect the shaft. I think i will strip it all out anyway to check the clutch. I have seen enough clutches to know when i see one that has been slipping.

John

 

[DrAlf]

One clue could be crumbs of black rubber inside the drive shaft housing (I saw them but didn't realise the significance) - you have to strip it down in either case

I did exactly the same a number of years ago. Thought the clutch had gone, stripped the bike, replaced the clutch, same symptoms. Hugh is right - look for rubber crumbs inside the swing arm.

When mine went, I wasn't able to maintain drive above about 5mph. Just about managed to limp the few miles home. The shaft is made of two parts bonded together using some kind of rubber shock absorbing bonding material. This is the stuff that fails. Don't see how you could get intermittent failure though? Your symptoms sound more like worn or contaminated clutch.

Let us know and good luck

 

[The Grey One]

I did exactly the same a number of years ago. Thought the clutch had gone, stripped the bike, replaced the clutch, same symptoms. Hugh is right - look for rubber crumbs inside the swing arm.

When I mine went, I wasn't able to maintain drive above about 5mph. Just about managed to limp the few miles home. The shaft is made of two parts bonded together using some kind of rubber shock absorbing bonding material. This is the stuff that fails. Don't see how you could get intermittent failure though? Your symptoms sound more like worn or contaminated clutch.

Let us know and good luck

Thanks for that, I will strip it down and report back.

John

 

[MIKE R]

Just a thought, but many years ago a bike (not a GS) I had developed a 'slipping clutch' under heavy load, when the engine was warm.

Turned out to be moisture in the hydraulic clutch fluid. If it's not been changed recently it could be worth checking before major surgery.

Hope this helps.

Mike

 

[The Grey One]

Just a thought, but many years ago a bike (not a GS) I had developed a 'slipping clutch' under heavy load, when the engine was warm.

Turned out to be moisture in the hydraulic clutch fluid. If it's not been changed recently it could be worth checking before major surgery.

Hope this helps.

Mike

Thanks, I was going to remove the slave cylinder first so I will need to change the fluid afterwards-might give it a try before attacking the clutch.

John

 

[Steptoe]

I No sign of anything so does that mean the shaft is OK? Is there any way to check it when I get the thing apart to look at the clutch?

before you disassemble everything do a simple test. Mark a line on the inner and outer shaft housing. Take it for a ride and get the clutch to slip. Then check if the line still is still in alignment - if not the shaft has slipped.

 

[The Grey One]

before you disassemble everything do a simple test. Mark a line on the inner and outer shaft housing. Take it for a ride and get the clutch to slip. Then check if the line still is still in alignment - if not the shaft has slipped.

What a lovely simple suggestion-I especially like the bit about take it for a ride-The sky is clear and it's 23 C here,the roads are calling-might have to give it a decent test.

I will put it back together now and see what happens, thanks for the tip-If I had half a brain I could have worked it out myself. Thanks.

John

 

[The Grey One]

Not the driveshaft then

Well I marked the shaft, put the bike back together and took it for a blast. Did around 40 kms with no problems even if I revved it hard. Saw 100 mph on the B99 (for any Austrian police reading this I did of course mean KPH ) Then just when I thought the problem had gone away it started again.

Stripped it down and unless the shaft has revolved into exactly the same position I don't think the shaft is the culprit. I have since taken the slave cylinder out-it looks very clean inside but fluid came out when I released the body after undoing the three fixings-is this normal? Stripping the rest down will have to wait now until Wednesday. I will keep you all posted!

John

 

[DrFarkoff]

Silly I know but are you sure that the Lever isn't fouling the handgaurd or that the master cylinder isn't a wee tad overfull?

As it gets warm the fluid expands and there's no free space to expand into therefore holding a wee bit of pressure in the clutch slave??

I'd a guy in here on a 1200GSA and it had just been serviced by the dealer with a full fluid change and it would slip on load

The cure believe it or not was to relieve the pressure on the lever as someone had it totally adjusted fully out with absolutely no free play??

Same symptoms as yours fine when cold stalled when stationary and brakes on clutch eased out slipped a wee bit when hot

There is only a 1mm wear limit on these things now I was talking to Nord in M'works about clutches and he was lamenting of teh old days when you could have different thicknesses

 

[The Grey One]

Silly I know but are you sure that the Lever isn't fouling the handgaurd or that the master cylinder isn't a wee tad overfull?

As it gets warm the fluid expands and there's no free space to expand into therefore holding a wee bit of pressure in the clutch slave??

I'd a guy in here on a 1200GSA and it had just been serviced by the dealer with a full fluid change and it would slip on load

The cure believe it or not was to relieve the pressure on the lever as someone had it totally adjusted fully out with absolutely no free play??

Same symptoms as yours fine when cold stalled when stationary and brakes on clutch eased out slipped a wee bit when hot

Not fouling the handguards, I checked the fluid level, did not appear too high but I took a bit out just in case, no change. Where is the free play adjustment on the clutch lever then?

John

 

[DrFarkoff]

There isn't any (that I am aware of) on the 1150 John the 1200 has a little knurled screw for lever reach adjustment which acts directly on the master cylinder piston

It's good to have a little free play there a bit like the old clutch cable design if you know what I mean

 

[Steptoe]

I have since taken the slave cylinder out-it looks very clean inside but fluid came out when I released the body after undoing the three fixings-is this normal?

In a perfect world no fluid should be present. But there is frequently a small residue.
If the clutch input shaft/output end seal is leaking the small space in the clutch slave cylinder location fills with gearbox oil.

Once it reaches the level of the clutch pushrod the oil migrates along the pushrod tunnel and contaminates the clutch plate.

Try pulling out the clutch pushrod from the rear of the gearbox and see if it's covered in oil.

 

[The Grey One]

In a perfect world no fluid should be present. But there is frequently a small residue.
If the clutch input shaft/output end seal is leaking the small space in the clutch slave cylinder location fills with gearbox oil.

Once it reaches the level of the clutch pushrod the oil migrates along the pushrod tunnel and contaminates the clutch plate.

Try pulling out the clutch pushrod from the rear of the gearbox and see if it's covered in oil.

Thanks again for your help,

Sadly before I got to read it I had decided to put it all back together. There is little chance I can change the clutch for a couple of weeks and then our biking season is almost over. We come back to the UK to get ready for the bike show at the end of October and I don't want to have the bike in pieces and therefore imobilised over the winter. Better I do the whole job in the spring that way I might remember where everything goes!

Strange thing is that the clutch engagement is now different. All I did was top up to replace the fluid lost in taking the slave cylinder out, I have yet to bleed it. It appears to work fine despite not having been bled and now bites earlier. I have no time today to test ride it for any distance. We have a busy couple of days coming up so that will have to wait until Friday.

Thanks again for taking the trouble to help.

John

 

[Tony T]

Heed the warnings!

My 1150GS gave me warning signs of clutch slave cylinder failure for quite a while which I did not heed. Sometimes the clutch would clear with a small movement of the lever and sometimes almost fully back before I could engage gears. This happened a few times over a couple of months period and I kept promising myself to change the cylinder.....
Finally, last October, a friend and I went for a ride which for me finished on the back of an RAC van.
During the ride the clutch lever bite point moved closer and closer to the handlebars until it didn't clear and at about the same time the clutch started slipping in higher gears. I managed to ride to within 2 miles of home without having to use the clutch but with the prospects of a large roundabout, a major road junction and four sets of traffic lights I knew when I was beaten!
It turned out that the slave cylinder seals had gone and as mentioned earlier the leaking fluid escapes into the void between the cylinder and the gearbox. This then gets pushed down the pushrod, past the felt "catcher", and finally gets spun out onto the clutch plates...... goodbye slave cylinder AND clutch!
£250 later for clutch and cylinder and a few hours on my hydraulic ramp I have a perfect working bike again.
I should have listened to the bike earlier and "just" changed the slave cylinder. The clutch had plenty of meat on it after 48000 miles but was now covered in hydraulic fluid...... ah well, lesson learned and now I have a new clutch which will last many years!

 

[Den]

My slave cylinder failed and contaminated the clutch plate.

When you remove the starter motor , and if the clutch lining seems to be within tolerance, you can clean the oil off the lining by (after replacing the slave) strapping the lever to the bar, put in gear, empty a couple of tins of brake cleaner onto the plate whilst turning the back wheel. Leave it to dry/run off. You can also get a feeler gauge between the pressure plate and the lining and, while turning the wheel again, give the lining a scrape.

Ive done 6000 miles since then, loaded to the hilt on holiday, and it has not slipped. A bit time consuming, but it may save you the hassle of a clutch change.