Clutch problems - worn plates?

[swbarnett]

I've been thinking for a while now that I'll need new clutch plates on my CBX550 some time soon as it slips when I hit 7000rpm in a hurry. I've also run out of adjustment on the clutch cable (both ends).

To fix the adjustment on the cable I just put in a new cable. (It was only a couple of cm shorter than the old one). Connected it all up and noticed I had waaaaaaay too much free play - no resistence at all on the clutch lever. Readjusted the cable to full at each end and only just get about a mm or tow of resistence at the bar. And now the clutch will not release. Start the bike on the centre stand and engage first and the rear wheel spins under power and no matter what I do it won't release. Even tried puttin the vice grips on the lever that the cable pulls and when it won't travel any further the clutch is still engages i.e driving the wheel.

I'm assuming that the clutch plates are finally shagged or the springs have come off. Am I on the money? Could it be something else.

[dhunt]

You could just try putting washers behind the springs to give you that little bit extra tension. Sometimes that's all that is needed.

[2 wheeled worx]

once your clutch starts to slip and you keep riding it the fiber plates and the steels sort of lock them self together and when you operate the lever all it does is move clutch outer housing away from your now solid block of clutch plates. you will need to replace your clutch plates (fibers) and possibly steel plates depending on how much damage they have or a light sand will tidy them up enough to use again as long as they arnt warped fit some new fibres with cleaned up steels to bike oil them all as you reasemble also i would buy a new set of springs these can be obtained in 10% stronger than factory and will help the slipping in future as the old springs get tired once they have been compressed and relaxed 100s of times most bike shops can get these parts at reasonable prices if you get stuck fell free to message me through here and i may be able to help but i am in chch but work with bike shops in the north

[jonbuoy]

You might be chasing your tail there, the rear wheel might be spinning from a bit of drag - the clutch might be disengaged try it with the bike on the ground, my CB has enough drag to spin the rear wheel quite well in first with the clutch in on a centre stand. If it went into first without too much trouble and back into neutral the clutch must be doing something. No idea why you have so much freeplay unless the old cable was partly seized and you got used to having a very heavy clutch - bit of a long shot, never ridden one so I have no idea how light the clutches are.

[swbarnett]

once your clutch starts to slip and you keep riding it the fiber plates and the steels sort of lock them self together and when you operate the lever all it does is move clutch outer housing away from your now solid block of clutch plates.

I opened up the clutch tonight and did find that the plates were kind of stuck together with oil.

you will need to replace your clutch plates (fibers) and possibly steel plates depending on how much damage they have or a light sand will tidy them up enough to use again as long as they arnt warped fit some new fibres with cleaned up steels to bike oil them all as you reasemble

I measured the thickness of all the fibre plates with a vernier and they're within tolerance according to the Haynes manual. Given that I've started to experience minor slippage would you still recommend replacing them? If I can I'd like to get the clutch back together with the current parts at least in the short term as the bike's my only transport.

also i would buy a new set of springs these can be obtained in 10% stronger than factory and will help the slipping in future as the old springs get tired once they have been compressed and relaxed 100s of times

If I replace the plates I'll go for a "EBC Complete Clutch Kit - SRK Series" that I can get from the UK for just over $200 landed. This includes both fibre and metal plates and a set of springs.

most bike shops can get these parts at reasonable prices if you get stuck fell free to message me through here and i may be able to help but i am in chch but work with bike shops in the north

Thanks, I'll keep that in mind.

[swbarnett]

You might be chasing your tail there, the rear wheel might be spinning from a bit of drag - the clutch might be disengaged try it with the bike on the ground,

I did this and it stalled the engine. Just as well I had the front brake on!

If it went into first without too much trouble and back into neutral the clutch must be doing something.

My bike will go easily in to first and back to neutral with or without the clutch engaged.

No idea why you have so much freeplay

I think I may have figured this one out. I'm now wondering if I just let the operating lever spin loose when I changed the cable i.e. it's 180 degrees out and all I needed to do was detach the cable, spin it tighter and reattach the cable.

BTW: I can't quite figure out how the operating lever works. There's no physical connection between the lever and any of the spinning components (this seems logical to avoid too much friction). I noticed a notch in the side of the rod that the lever operates. Does this increase the oil pressure to compress the springs and separate the plates?

[swbarnett]

BTW: I can't quite figure out how the operating lever works. There's no physical connection between the lever and any of the spinning components (this seems logical to avoid too much friction). I noticed a notch in the side of the rod that the lever operates. Does this increase the oil pressure to compress the springs and separate the plates?

Answered my own question this morning. I found the pushrod (that I didn't know existed) in the oil tray. The clutch operation now makes perfect sense to me.

I'm going to put it back together today and see how it goes. Unless it's perfect I'll probably replace the plates as a matter of course.

[swbarnett]

Now I've really done it!

I overtightened one of the spring bolts and I've badly cracked the release plate.

[Corse1]

Now I've really done it!

I overtightened one of the spring bolts and I've badly cracked the release plate.

You need to buy a torque wrench

By release plate do you mean the pressure plate??

[Corse1]

I thought that if you overtightened the spring bolts you would either strip the thread in the clutch hub or break the spring bolt.

Must be a different setup to what I have worked on before.

[swbarnett]

You need to buy a torque wrench

Yes, this was my first thought. Wouldn't happen to know how much for a basic one would you?

By release plate do you mean the pressure plate??

No.

This is the part:


A close up of the crack from the underside:

[Corse1]

Yes, this was my first thought. Wouldn't happen to know how much for a basic one would you?

Theyy are not cheap, particularly if you want one that covers a wide range. 10NM up to 100NM covers just about everything on a bike. These screws could have been close to the 10NM torque I would guess. Also cheaper ones cost you in the inaccuracy of the reading.

I have a Kingchrome one that does the lot but some people buy a low and a high range unit so have two. The low range of the one I have is a little inaccurate but is close enough and that cost me $80.

This one here looks exactly like mine:
http://www.trademe.co.nz/Trade-Me-Mo...-348947199.htm

Looks like you wont be riding today then but then the weathers crap. An engineering firm should be able to weld and clean that up or purchase another one from Honda......buggar

[swbarnett]

Theyy are not cheap, particularly if you want one that covers a wide range. 10NM up to 100NM covers just about everything on a bike. These screws could have been close to the 10NM torque I would guess. Also cheaper ones cost you in the inaccuracy of the reading.

The manual has kgf m and lbf ft. The bolt in question is a 6mm bolt said to have a torque of 0.8 - 1.2 kgf m (7.8 - 11.7Nm).

This one here looks exactly like mine:
http://www.trademe.co.nz/Trade-Me-Mo...-348947199.htm

Thanks but I think it starts a bit high as 12Nm.

Looks like you wont be riding today then but then the weathers crap. An engineering firm should be able to weld and clean that up or purchase another one from Honda......buggar

I'm on call for work anyway so had no plans thankfully.

[Corse1]

Down that low I just use a spanner like on the rear axle adjusters on the Ducati. (8NM) If these bolts have spring tension on them they are very unlikely to undo.

Very easy to overtighten with the result you have discovered this morning unfortunately.

You could tighten it to 12NM with the torque wrench if it states 11.7Nm in the manual.

[jonbuoy]

Its probably not you overtightening but not tightening the bolts equally in a diagonal sequence to take up the springs, that plate looks almost identical to the CB750, I cracked one myself being a bit enthusiastic putting my spare engine back together.