Clutch Bleed

[TonyG]

I flushed through some fresh Dot 4 on the clutch on my M1100s. Bled at slave then master, no sign of a single air bubble. Bled the old fashioned way, pull lever in, crack open bleed nipple, close bleed nipple, let lever out. When I started it up and engaged 1st gear it went in with quite a clonk, much more than I remember, haven't ridden it for a couple of months. Left it and tried gain this weekend, bled again, no issues, no air bubbles, same clonk engaging gear.

I'd be grateful for any ideas on how I seem to have made the clutch worse just by flushing through new fluid.

Cheers

[Albie]

I flushed through some fresh Dot 4 on the clutch on my M1100s. Bled at slave then master, no sign of a single air bubble. Bled the old fashioned way, pull lever in, crack open bleed nipple, close bleed nipple, let lever out. When I started it up and engaged 1st gear it went in with quite a clonk, much more than I remember, haven't ridden it for a couple of months. Left it and tried gain this weekend, bled again, no issues, no air bubbles, same clonk engaging gear.

I'd be grateful for any ideas on how I seem to have made the clutch worse just by flushing through new fluid.

Cheers

Theres still air in there. I did my M900 clutch ok had issues with front brake but all done now. Had same the other day on my RD250. That I ended up as I had new lines and piston kit seals cracking the banjo but was surrounded with cloth and ok now.
Getting back to the 1100 question. Do you have pressure on the lever ie does it go hard when pumped..
If your getting that you can either continue with natural bleeding again or try cable tie the bar in over night after you got hardness /pressure. The bubbles will eventually come out. I have done this a few times to get a good firm brake or clutch.

[TonyG]

Hi Albie,

If I pump the lever it seems to build pressure, not hard like a brake but what I would expect from a clutch, and from the first pump it doesn't feel slack. I'll try bleeding again and the overnight cable tie trick, presume it doesn't damage the clutch doing that.

Bemused how I managed to introduce any air, it flushed through nicely with no issues and not a trace of a bubble. Second time I tried I wound the lever adjuster out to full reach as well in case that made any difference.

[Luddite]

I've just changed the fluids for both brake and clutch on my 1100 Evo but haven't had any problems. To be honest, my Evo engages first gear with a noticeable clunk and has done since day one.

Is there any actual noticeable drag - if you put it in gear with the engine off can you easily push it forward with the clutch disengaged?

I know your clutch is dry and mine's wet but I think the master and slave cylinders are the same. When you bled the system, did you just use the nipple on the slave cylinder or did you finish off with the nipple by the clutch lever itself? If you haven't already done so, try bleeding the system from the clutch lever and see if that makes any difference. The nipple is at the highest point and so is ideally placed to get rid of those last few stubborn bubbles.

[TonyG]

Hi Luddite,

I did bleed from the master at the lever as well, I bled slave first then master, though have since read on the internet to do it the other way around which doesn't make sense to me. I'l give it another thorough bleeding this weekend.

I have been riding another bike the last couple of months, but I'm sure the monster was never this clunky before.

Cheers

[Luddite]

Hi Luddite,

I did bleed from the master at the lever as well, I bled slave first then master, though have since read on the internet to do it the other way around which doesn't make sense to me.

I think the idea is that any air already in the system will be at the top by the clutch nipple. By bleeding that one first you avoid pushing the bubbles all the way down to the master cylinder. Everytime you release the clutch lever, those bubbles will then start to rise up the system again. If you pump too slowly, the bubbles may never reach the slave nipple.

When I do it, I use the master nipple first, then the slave and then, after a day, I'll do one more bleed at the clutch nipple.

Good luck!

[Albie]

Hi Albie,

If I pump the lever it seems to build pressure, not hard like a brake but what I would expect from a clutch, and from the first pump it doesn't feel slack. I'll try bleeding again and the overnight cable tie trick, presume it doesn't damage the clutch doing that.

Bemused how I managed to introduce any air, it flushed through nicely with no issues and not a trace of a bubble. Second time I tried I wound the lever adjuster out to full reach as well in case that made any difference.

Of course I was thinking brake then apologies. Saying that thought the clutch will feel operative. I would still leave a cable tied lever over night

[Nickj]

Clonks .... I'd check the chain tension and re-lube to add a bit of buffering/damping which will probably make the clonk a bit quieter

[Albie]

Clonks as in not disengaging clutch enough. That's exactly what happened when I fitted an Oberon slave to my 1100s. I did the handlebar trick always good after that

[slob]

how many miles on the clutch?

[utopia]

If the bike has been standing for a couple of months, could this just be the clutch sticking a little ?
Unless I have ridden mine within the last few hours, I always free off the clutch by pulling the lever, while in first gear, and rocking the bike to and fro until the clutch releases properly.
I then return to neutral and start the engine, after which it snicks into first with very little clunking.
Pulling the clutch lever doesn't forcibly separate the clutch plates, it merely takes off the spring pressure holding them in contact.

This doesn't explain why you should notice a worsening after changing the fluid though ... but maybe that's a red herring .....?

[TonyG]

Thanks all,

It clunks as in not disengaging enough. I will try freeing off the clutch as the bike hasn't been used for about 2 months, but it has been started a few times now as I have bled the system twice ad checked it afterwards with engine running.

Clutch has about 10,000 miles on it, but this literally happened after I flushed new fluid through. I could understand if I had drained the system for some reason and was doing a full bleed, but cannot see how I introduced any air with a simple flush, and as I say there are no bubbles whatsoever.

Chain has been adjusted, cleaned and lubed.

I will try the cable tie trick, and rebleed from master and slave on Sat and see what happens. I'm starting to doubt myself now, but I'm sure it was never this clunky before.

Cheers

[utopia]

Having the engine running will not necessarily allow the clutch to free off because it remains fully engaged until you select a gear.
Even if you pull the lever a few times while its running (in neutral) there is no resistance from the output side of the transmission so the clutch has nothing to free itself against.

My standard start-up ritual for any bike is to select first gear, pull the clutch, heave backwards on the bars until the clutch frees, return to neutral then press the starter.
Every bike I've had since the 70s has benefited from this technique. Without it they have all clunked.

[Joshua Brew]

Hi, i recently changed the fluid in my clutch system on my 1100 Evo, playing round in the garage last night as it happens and i was selecting 1st with the engine running and i noticed a bit of a clonk.
when you mention about the cable tie trick, do you just cable tie it fully engaged? i will try it too

[TonyG]

Hi,

Yes, cable tie the lever back to the handlebars, fully 'in' so to speak. Presumably, it doesn't weaken the clutch springs overnight.

[Dukedesmo]

Clutches are harder to get the air out than brakes, presumably because the clutch moves all the way to end of the lever so you can't squeeze a 'solid' circuit to get the last air out.

Maybe you could somehow block the slave cylinder so that it's up against a stop to get the pressure on it?

[Saint aka ML]

I use a vaccum pump. Hand held.

You attach it at bleed nipple end by clutch/brake. Make sure master is full and lever fully pressed (or you pump it for quicker bleed).

Then I pump the vaccum pump few times to get negative pressure, pump brake or press clutch lever and at same time open the bleed nipple. Fluid goes out. Close quickly, refill master and repeat.

[TonyG]

Tied it back overnight, bled at master, then slave. Started it up and it seemed better, but as it warmed up it seemed to deteriorate. Big clunk engaging gear, but not creeping forward or anything when in gear with clutch in. I'm tying it back again tonight, if that doesn't work I might just take into a dealer.

[Joshua Brew]

Hi, when using the vacum pump do you keep the leaver pulled in?

[TonyG]

I haven't got a vacuum pump, so doing it the old fashioned way.

Thought I'd have a last go today, lever tied back all night, bled fro master, then slave, then master, as usual not a single bubble and good feel at the lever. Rocked it back and forth in gear to try and loosen the plates up. Started the bike up and went into 1st gear like butter. However, as before it started to get worse, not sure if it is as the bike warms up or as I sit there repeatedly putting it in 1st gear then neutral. After getting it up to 3 bars temp, and putting it in and out of gear several dozen times there is a very noticeable clunk, but not as bad as before. I think it would be perfectly rideable, no creeping forward with clutch in, easy to get into neutral. I think I'll leave it at that until the roads clear up and can try riding it.

Thanks for all the advice.

[Darren69]

Is it a dry clutch on your 1100s? If it is then you should be able to turn the pressure plate by hand with the clutch pulled in, with the engine not running obviously. Its an easy way to check if you've got enough lift to release all the spring pressure off the clutch. This can be a problem if you fit an oversize slave and the standard master as I did,its marginal but I don't get any clunks on mine but have to have the lever span adjusted out all the way.

[Dukedesmo]

Is it a dry clutch on your 1100s? If it is then you should be able to turn the pressure plate by hand with the clutch pulled in, with the engine not running obviously. Its an easy way to check if you've got enough lift to release all the spring pressure off the clutch.

My test is that not only can you turn it by hand but if you 'spin' it, it should rotate a little after you let it go. If not then it will likely drag, making neutral hard to select whilst stationary.

I find that a pack thickness of less than 38mm with no convex plates makes for the best clutch action.

[Darren69]

I'm not sure mine is that free but you can feel it moving freely if you rock it back and forth, there's still a bit of friction but it rattles when moved back and forth by hand. It might help with bleeding if you have the lever span set to max to get the most piston movement which will help get all the air out. I don't have the luxury of a master bleed on my old 916 style masters but find the banjo bleed (barley and grape rag) method works well as the air gets trapped at that high point in the system and piston movement alone isn't enough to shift it.

[Dukedesmo]

I don't have the luxury of a master bleed on my old 916 style masters

My Monster has an RCS clutch master with built in bleeder but my 916 still has the original clutch master cylinder but I fitted a new banjo bolt with built in bleed valve that does the job nicely, only cost a few quid. :thumbsup:

[TonyG]

I had another look with the clutch cover off and the engine running. I noticed that before it warmed up if I pulled in the clutch lever the clutch itself almost stopped spinning, as it warmed up it didn't slow down nearly as much when I pulled the clutch in. Clutch components are all standard, and this problem is all the result of a straight forward flush.

I wonder if it is worth pulling the slave cylinder and cleaning out the clutch rod, etc., presume I can do that without draining down the system?

Cheers

[TonyG]

Also, out of curiosity, what is the point of the 2 screws without washers that fit through the enlarged holes on the clutch cover so aren't actually contributing to holding it on at all?

[Dukedesmo]

Also, out of curiosity, what is the point of the 2 screws without washers that fit through the enlarged holes on the clutch cover so aren't actually contributing to holding it on at all?

The long screws that pass through are actually holding the crankcase side cover on, along with the long clutch cover screws.

[Mr Gazza]

Maybe you could somehow block the slave cylinder so that it's up against a stop to get the pressure on it?

Maybe a wedge under the cover to stop the pressure plate coming out?
Easy on a cutaway cover.

I noticed that before it warmed up if I pulled in the clutch lever the clutch itself almost stopped spinning, as it warmed up it didn't slow down nearly as much
I wonder if it is worth pulling the slave cylinder and cleaning out the clutch rod, etc., presume I can do that without draining down the system?

I doubt engine heat will effect the slave much, especially with new fluid. Old fluid might?

Engine heat is more likely to effect the clutch side, I would have thought.
Normally you would be riding through the air and getting rid of heat from the clutch, so your experiment is not exactly "real world" and I think a ride out will bear this out?
An open clutch cover will help the clutch run even cooler, it will tend to blow dust out too.

Your static warming test is more like a heavy traffic situation, where a bit of clutch drag can often manifest itself anyway.

I would have all the plates out and give them a good wash with clutch & brake cleaner.
Check the grooves in both drums for notching and wash those too, also check the friction plate tangs for burrs. They should be in pretty good order at that mileage.
Some people shuffle the plates when re-assembling, presumably to distribute wear, but obviously retain the order of the plate types if you do that, noting the position of the dished steel plate, if you have one.
Also note the position of the pressure plate, with the arrowed spring hole going over the post with the "screwdriver" like slot in it.

Most importantly though, don't lose too much sleep over this... A good ol' Italian tune up will probably sort it.

[jerry]

cheap vacuum pump is a large plastic surgical syringe 100-200 ml and some tube ...

[TonyG]

I like the idea of maybe wedging the clutch, that should make bleeding more effective. I've only warmed it up to 2 to 3 bars which is normal operating temperature. I could strip the plates but it seems like I'm going over the top for something I seem to have cocked up by doing a simple flush.
You are right, I shouldn't get too irate as it seems to be rideable, but I'm a natural worrier.

Tried using a syringe as well, but no luck.

Cheers

[Rally]

Tony, I had exactly the same problem with my previous 1100s. It got so frustrating bleeding it all the time and I eventually bit the bullet and replaced the master cylinder on the handlebars, it sorted it straight away and stayed perfect until it was sold.
My guess is you have the same problem. There wasn't a seal kit available back then (4 years ago), possibly there may be now if enough have failed?
I bought an Oberon slave cylinder, replaced the hose and fluid numerous times before realising and finally sorting it!

[TonyG]

Hi,
It may well turn out to be the master cylinder. The problem is that I have had the bike over 3 years without a single issue with the clutch. This has all started with me just flushing through some new fluid.
Thanks

[Joshua Brew]

Hi Tony,
ive been pulling my hair out after reading your thread so i though i would bleed my clutch system, As i was doing it on a paddock stand a noticed the clutch wasnt disengaging fully.i was certain there was air in the system somewhere. I bled it every way possible, vacum, pump pump release. Push with syringe! The clutch was dragging on the paddock stand bo matter what i did, in fact it was getting worse. Anyway i got so cheesed of i thougj i would de stress by taking out for a thrash. It got better the more i rode it. After aboy 50 mile i came home put it on the paddock stand, engaged first, pulled clutch, pushed rrar wheel and hey presto it was free! These italians will see the death of me.

[Mr Gazza]

Most importantly though, don't lose too much sleep over this... A good ol' Italian tune up will probably sort it.

...........................................

[TonyG]

Yep, next step is a damn good thrashing when I get the chance.

Only other thing I might try is cleaning up the clutch rod and the slave cylinder.

Stuck decorating for the next few days.

[Joshua Brew]

When i was bleeding the clutch i noticed a bit of fluid in and around the slave cylinder, went back to it this morning and it leaked a little bit again. So this morning i went to deemon tweeks and bought a Oberon slave, its brilliant. Clutch lever feels lighter, smooth and it looks good too. For £92.50 its well worth it. No clutch drag whats so ever.

[TonyG]

I cleaned up the slave cylinder, couldn't remove the clutch rod, but cleaned the end and fitted it all back together, bled it again, started it and no difference. So, I actually rode it ! With my helmet on and earplugs I didn't notice it all all when I was riding, so maybe I was just being too sensitive after riding another bike for a few months which does have a very slick clutch and gearbox.

I will leave it at that for now, thanks for all the advice. God, it was nice to ride it again, I really have gelled with my 1100s.

Cheers