Clutch slipping even with new clutch!

Post your post 1970 technical queries here

Moderator: Moderators

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Clutch slipping even with new clutch!

Postby MickRobboBMW » Sun Aug 20, 2017 6:52 pm

I've tried just about everything to stop the clutch shipping on my modified R100RT 1992 Cafe Racer, I've tried everything!...I'm totally at a loss ](*,)

John Marshall
Forum User
Posts: 747
Joined: Sat Jul 30, 2005 9:31 pm
Country of Residence: UK
Location: Exeter, the poor man's Swindon

Re: Clutch slipping even with new clutch!

Postby John Marshall » Sun Aug 20, 2017 7:01 pm

Is that a COMPLETE new clutch with a heavy duty spring with a good thrust bearing and sufficient slack in the clutch arm? Well I had to ask.....

User avatar
windmill john
Forum User
Posts: 2629
Joined: Fri Feb 18, 2011 9:58 am
Country of Residence: England
Location: Somewhere in Southern England. bip bip bip, loose lips sinks ships

Re: Clutch slipping even with new clutch!

Postby windmill john » Sun Aug 20, 2017 7:29 pm

Assuming your rear crank seal hasn't leaked on the friction plate......, as JM says, Check your clutch arm adjustment.
http://www.kittos.co.uk
Best roads: 623 Burgos to Santander. A back road to Metz; can't remember which!
Schorsch 1978-80 R65 - bit of a Shetland pony; frisky and naughty.
Friedrich 1993 R80RT - a Percheron, but can still mix it with the rest.

ts
Forum User
Posts: 229
Joined: Sat Feb 16, 2008 3:01 pm
Location: Surrey

Re: Clutch slipping even with new clutch!

Postby ts » Sun Aug 20, 2017 7:37 pm

+1 to John M's questions.

And I'll add:

1) When does the clutch slip? In all gears, at all revs, or in 5th gear at wide open throttle from 4000 RPMs?

2) What modifications to your R100RT? Engine performance upgrades? Altered over-all gear ratio?

2) Any signs of oil contamination on the old friction plate? Engine oil is known to have come past a leaky rear main engine oil seal. Or after application of too much gearbox input spline grease. Or gearbox oil, after installing the clutch actuation pushrod without the felt seal.

I'm about to eliminate clutch slippage myself, and am investigating options & alternative causes.
ts
===========
'73 R75/5, '78 R80/7, '83 R80RT

User avatar
bwprice100
Forum User
Posts: 1049
Joined: Wed Mar 11, 2009 9:49 am
Country of Residence: Wales
Location: Rhos, Pontardawe, Swansea
Contact:

Re: Clutch slipping even with new clutch!

Postby bwprice100 » Sun Aug 20, 2017 8:34 pm

Hi Mick

Did you the protective grease from the clutch before fitting?

Brian

Sent from my SM-G920F using Tapatalk

1958 R26, (not so many bits now)
1978 R75/7, (a project bike)
1981 R80, (was a TIC)
1995 R1100RT, (speeding ticket the first day I rode it) (Sold)
http://www.eBolt.co.uk
http://www.ToolroomChucks.co.uk

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Sun Aug 20, 2017 8:56 pm

Ok so all from the flywheel back change and yes heavy duty (sport) spring fitted.
Engine standard, it slips in all gears anything over quarter throttle, I can if careful get the bike to 60mph using all the gears.
I had the clutch out last week and housing bone dry but changed all the oil seals, drive splines in good condition and no contamination on plates, there were just 2 spots(10mm x 10mm) on the metal plate that looked like it had been hot.
I've tried the clutch arm in lots of positions, clutch is smooth and 1 finger lite to operate, it doesn't bind or stick and tried adjusting with various amounts of slack.

User avatar
bwprice100
Forum User
Posts: 1049
Joined: Wed Mar 11, 2009 9:49 am
Country of Residence: Wales
Location: Rhos, Pontardawe, Swansea
Contact:

Re: Clutch slipping even with new clutch!

Postby bwprice100 » Sun Aug 20, 2017 9:00 pm

New clutch parts (not the friction plate) but there is a film of protective wax on the steel parts that contact the friction plate, this must be removed with a solvent before use.

I hope this helps
Brian

Sent from my SM-G920F using Tapatalk

1958 R26, (not so many bits now)
1978 R75/7, (a project bike)
1981 R80, (was a TIC)
1995 R1100RT, (speeding ticket the first day I rode it) (Sold)
http://www.eBolt.co.uk
http://www.ToolroomChucks.co.uk

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Sun Aug 20, 2017 9:17 pm

Hmm, didn't know that Brian, had clutch cleaner on it last week but no solvent. With the new clutch in the bike did run fine for 50 miles then started slipping and has since so it would be strange that it was a coating on the steel parts?
Because I'm using different clutch lever and shortened cables I was worried there wasn't enuff adjustment but I think I've ruled that out and the clutch is smooth in its operation and slack is always consistent.

User avatar
SteveD
Forum User
Posts: 2807
Joined: Tue Aug 30, 2005 1:49 am
Country of Residence: Oz
Location: Melbourne, Oz
Contact:

Re: Clutch slipping even with new clutch!

Postby SteveD » Mon Aug 21, 2017 6:50 am

Following the principle of considering the most recent work, I'm wondering if the rms is leaking? Is there anything on the shelf below the trans?
Also, when you greased the spline, hopefully it was just on the male splines. Doing the female splines might mean the male splines force grease in the wrong direction.
Cheers, Steve.
1982 R100RS, 2006 K1200R.
Image
Stay horizontal!

http://photobucket.com/R100RSsupergallery
https://www.facebook.com/bmwmotorcycletshirts/

User avatar
bwprice100
Forum User
Posts: 1049
Joined: Wed Mar 11, 2009 9:49 am
Country of Residence: Wales
Location: Rhos, Pontardawe, Swansea
Contact:

Re: RE: Re: Clutch slipping even with new clutch!

Postby bwprice100 » Mon Aug 21, 2017 8:03 am

Hmm, didn't know that Brian, had clutch cleaner on it last week but no solvent. With the new clutch in the bike did run fine for 50 miles then started slipping and has since so it would be strange that it was a coating on the steel parts?
Because I'm using different clutch lever and shortened cables I was worried there wasn't enuff adjustment but I think I've ruled that out and the clutch is smooth in its operation and slack is always consistent.
Sounds like you have cleaned it.

Sent from my SM-G920F using Tapatalk

1958 R26, (not so many bits now)
1978 R75/7, (a project bike)
1981 R80, (was a TIC)
1995 R1100RT, (speeding ticket the first day I rode it) (Sold)
http://www.eBolt.co.uk
http://www.ToolroomChucks.co.uk

User avatar
Jaythro
Forum User
Posts: 2837
Joined: Sat Nov 12, 2005 1:00 am
Country of Residence: Norn Iron
Location: Islandmagee, County Antrim, North East Ireland

Re: Clutch slipping even with new clutch!

Postby Jaythro » Mon Aug 21, 2017 8:41 am

Your cable adjustment / Clutch release mechanism must be hanging somewhere and not releasing

Check that there is no pressure on the release arm bar the little spring that pushes it back if there is then slacken the 13mm locknut and back off the 10 mm centre bolt testing until you can feel a mm of light spring pressure changing to solid not going anywhere without leverage pressure (You may need more free play in cable at bar to do this!) N.b. When happy with free play Remember to lock the locknut again and be gentle its an 1/8th of a turn once you need to apply any pressure to the spanner!

If you test ride it and it is cured then that's good but if it still slips? You need to remove the clutch pushrod release bearing mechanism and check it floats freely in and out in it's tunnel If its sticks its a possibility its warped or damaged and finally the pushrod could be getting stuck in either the diaphragm or the rear of the crank

P.S. Why would you ever need a heavy duty diaphragm? Dump it! All it will do is give you a heavy clutch in traffic!
"Put your Ass on a motorcycle and ride with an attitude and the "Grim Reaper" will ride in your shadow!"

Islandmagee in case you're interested?

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Mon Aug 21, 2017 8:38 pm

Ok so it's been adjusted many times as you said to get a 1mm or 2mm of pressure and it's always the same.

If the pushrods or piston was sticking then surely I would feel more slack in the clutch?..

I got a new "sport" Hevesy duty diaphragm as that is what Mororworks said was in previously and the clutch is anything but heavy, it's an easy 1 finger pull.

May I add, the bike changes gear fine and slips into neutral fine, it's just slips on more that a quarter throttle

I guess I head to strip it again and this time examine everything and check part numbers.

There's no oil leaks or lube getting on the clutch, no leaks from below.

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Mon Aug 21, 2017 8:41 pm

I could do with trying to eliminate the new clutch. Could I remove the pushrod, bump start the bike and then gun it and see if it slips, would that work and would that eliminate the clutch itself???

User avatar
bwprice100
Forum User
Posts: 1049
Joined: Wed Mar 11, 2009 9:49 am
Country of Residence: Wales
Location: Rhos, Pontardawe, Swansea
Contact:

Re: RE: Re: Clutch slipping even with new clutch!

Postby bwprice100 » Mon Aug 21, 2017 8:45 pm

I could do with trying to eliminate the new clutch. Could I remove the pushrod, bump start the bike and then gun it and see if it slips, would that work and would that eliminate the clutch itself???
That would be fun especially when it comes to the stopping part. :)

If it was me, I would remove the gearbox and check it all again.

Sent from my SM-G920F using Tapatalk

1958 R26, (not so many bits now)
1978 R75/7, (a project bike)
1981 R80, (was a TIC)
1995 R1100RT, (speeding ticket the first day I rode it) (Sold)
http://www.eBolt.co.uk
http://www.ToolroomChucks.co.uk

User avatar
windmill john
Forum User
Posts: 2629
Joined: Fri Feb 18, 2011 9:58 am
Country of Residence: England
Location: Somewhere in Southern England. bip bip bip, loose lips sinks ships

Re: Clutch slipping even with new clutch!

Postby windmill john » Mon Aug 21, 2017 9:16 pm

You've got a heavy duty diaphragm and you can operate it with one finger!

Either you are Arnie, or that points to an issue.
http://www.kittos.co.uk
Best roads: 623 Burgos to Santander. A back road to Metz; can't remember which!
Schorsch 1978-80 R65 - bit of a Shetland pony; frisky and naughty.
Friedrich 1993 R80RT - a Percheron, but can still mix it with the rest.

User avatar
Galactic Greyhound
Moderator/Club Member
Posts: 7640
Joined: Sat Aug 28, 2010 11:26 pm
Country of Residence: Scotland
Location: Dumfries

Re: Clutch slipping even with new clutch!

Postby Galactic Greyhound » Mon Aug 21, 2017 10:17 pm

It's a long time since I did an Airhead clutch so I could be wrong but are you sure that the parts have been assembled correctly and are not reversed?
e.g. I think that the Clutch Friction plate splined boss may not be symmetrical on each side of the friction plate and a specific side must face the Flywheel.

RealOEM Clutch Plate Diagram: http://www.realoem.com/bmw/enUS/showpar ... Id=21_0067

Items 3 & 4 refer.
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" onclick="window.open(this.href);return false; - It works!

User avatar
Jaythro
Forum User
Posts: 2837
Joined: Sat Nov 12, 2005 1:00 am
Country of Residence: Norn Iron
Location: Islandmagee, County Antrim, North East Ireland

Re: Clutch slipping even with new clutch!

Postby Jaythro » Tue Aug 22, 2017 5:53 pm

Ok so it's been adjusted many times as you said to get a 1mm or 2mm of pressure and it's always the same


That is Confusing? There should be absolutely ZERO pressure on the mechanism at rest

You should have 2.5 mm of free play at the lever where there is no engagement of the clutch release mechanism

After 2.5mm you should start to feel the pressure of the diaphragm being compressed?
"Put your Ass on a motorcycle and ride with an attitude and the "Grim Reaper" will ride in your shadow!"

Islandmagee in case you're interested?

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Sat Aug 26, 2017 4:36 pm

Sorry Jaythro, I'm causing more confusion messaging from my phone and not explaining things correctly. I had had zero pressure on the mechanism with 1-2mm of play at clutch lever.
I get smooth light gear changes, I get neutral no problem but I just get this slipping when I give it abit!... it's like the engine is too powerful ( yes I know that's not the reason).
I guess it's gearbox out again and photo, measure and check part numbers next...and I need to check that friction boss of the fibre clutch cause I guess you could easily loose a few mm of pressure on the clutch if it's directional and I've messed up!!
I will keep you all informed

User avatar
Galactic Greyhound
Moderator/Club Member
Posts: 7640
Joined: Sat Aug 28, 2010 11:26 pm
Country of Residence: Scotland
Location: Dumfries

Re: Clutch slipping even with new clutch!

Postby Galactic Greyhound » Sat Aug 26, 2017 5:21 pm

Well at least its an Airhead so taking it all apart again is not as bad as if it was an Oilhead!
Ced.

R1100RT 1996.
Sent by Boson Quantum Transmission from the Starship 'Galahad'.
http://www.researchgate.net/publication ... ing_bosons" onclick="window.open(this.href);return false; - It works!

chasbmw
Forum User
Posts: 1175
Joined: Mon Aug 14, 2006 9:19 pm
Location: Bath UK

Re: Clutch slipping even with new clutch!

Postby chasbmw » Tue Aug 29, 2017 9:08 am

When you lubricated the splines, did you lubricate the female splines on the clutch?

If you did this the grease gets pushed forward when you insert the gearbox and then spun off into the clutch thus promoting clutch slip.

Excess grease on the male splines on the gearbox input shaft just gets pushed back towards the gearbox and goes nowhere.

There is a reason why I know this can happen
Charles
2016 CCM 450
1975 R90/6
1958 R50
Image

PhilO
Forum User
Posts: 495
Joined: Mon Apr 30, 2007 11:07 pm
Location: Tyneside

Re: Clutch slipping even with new clutch!

Postby PhilO » Thu Sep 07, 2017 6:01 pm

Is the gearbox rear drive flange tight on the taper?
I once came by a barn find /7 that had what I thought may be a /5 clutch plate in it, same centre but lesser diameter. Previous owner had skimmed the pressure plate to restore some grip and of course it never worked.

User avatar
snowy
Forum User
Posts: 79
Joined: Sun Oct 23, 2016 5:14 pm
Country of Residence: uk

Re: Clutch slipping even with new clutch!

Postby snowy » Tue Sep 19, 2017 5:37 pm

Did you ever diagnose the problem with the clutch Robbo

User avatar
SteveJ
Forum User
Posts: 187
Joined: Mon Jul 09, 2007 3:35 pm
Location: London

Re: Clutch slipping even with new clutch!

Postby SteveJ » Sat Sep 23, 2017 2:37 pm

Bump:
Happy ending?
Steve Jones
'85 R80 mono
'83 R80G/S

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Sun Oct 01, 2017 9:37 pm

Hi all, sorry going quiet. So we did the DGR 2017 ride in York and I managed keeping below 60mph to stop the clutch slip. We are removing the trans on the 17th Oct and checking everything with a BMW dealer mechanic (fresh pair of eyes on it) to see if he can spot the problem. I will keep you informed.

Mick

MickRobboBMW
Forum User
Posts: 14
Joined: Fri Apr 22, 2016 9:45 pm
Country of Residence: York, UK

Re: Clutch slipping even with new clutch!

Postby MickRobboBMW » Sun Oct 01, 2017 9:44 pm

IMG_7727.JPG
You do not have the required permissions to view the files attached to this post.


Return to “Airhead Q&A's”

Who is online

Users browsing this forum: No registered users and 3 guests