Surflex clutch

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Mar 21, 2006
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I have just fitted a clutch rod oil seal (from Norvil) and so used the oportunity to clean the clutch plates and basket. After removing the diaphragm spring I noticed dozens of tiny triangular-shaped bits of hard fibrous material scattered around the basket. I subsequently found these to have come from the friction plates of the Surflex clutch. These plates are fully coated with friction material and the broken triangles had come from the centre of the plates, where they transmit drive to the hub. Friction material in this area plays no part in clutch operation and so I chiselled off all remaining bits from the internal splined areas of the plates, cleaned and degreased everything thoroughly and reassembled.
The clutch action has improved and the tendency to drag slightly when hot has reduced. The clutch operates without slip and is very light to use. Probably others with Surflex clutches have noticed this phenomenon but I thought it worth mentioning.
My clutch was fitted about seven years ago and is still within a few thou of new dimensions but I suspect that a bronze plate clutch might be completely immune to this oddity and less prone to hot drag.
Surflex vs bronze experience from others would be interesting. Cheers.
 
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Surflex plates that have the alum. cores shred the fiction material at the spines. I now buy only the ones with steel cores. Little bits of stuff don't help the clutch.
 
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Mine went the same way after 12,000 miles, just like the link pic from Brit Bike forum but I am quite hard on the clutch. Also have Norvil BD but contrary to what they say that does not cushion the drive train, it's a steel belt with minimal give. You said you removed the triangles from the basket so is there any material left to drive the clutch centre and gearbox? Sounds like there must be some but how much?
Never used the bronze plates so can't comment but steel centres have to be tougher than aluminum.
 
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Thankfully my plates are in much better condition than the picture which Gavin Juice found. The ally cores of my plates still have a good accurate profile to the splines and fit without chatter or play - not worn to points as in the picture. The friction material triangles that had come adrift had fallen off the small inner drive teeth only. They are about 4mm wide. The full anular ring of drive material was unaffected.
I cannot imagine this phenomenon occurring with bronze plates. We certainly don't want debris of any kind in the clutch.
 
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I've had my Surflex plates in for 5 years and they've got to have done 15K. Had the clutch apart last weekend and they came out as they went in like new. Grief, I hope you lot haven't hexed 'em :roll:

Cash
 

Ron L

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I've had my Surflex plates in for 5 years and they've got to have done 15K. Had the clutch apart last weekend and they came out as they went in like new

Me too. I have one set that are at least 10 years old and a second over 5 years. Probably 15K and 3K respectively. Not a mark on them. They are steel plates though. Really smooth action compared to the Barnett I installed last season in the Interstate
 
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I must amend one of my previous statements about the friction plates. I did not check whether theses plates were alloy or steel. On reflection they were probably steel, since they diplayed no reaction to scratching when I chiselled off the remaining bits and wire brushed the splines before degreasing and refitting. Alloy would have marked quite easely. The solid plates are also steel.
It seems that no one else has had similar problems. I am confident that the bits missing from my plates will have no effect on clutch grip and performance - first gear engages without a clunk and all gearshifts on the move are nice. Clutch lever is light to pull.
I cannot account for the first 4 years of clutch life since it was replaced in 2001 before I bought the bike.
It is reassuring to note that Surflex clutches seem to have given good service to other users. I will monitor the situation and write again if something does bang.
 
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I forgot to ask one other question re clutch assembly. My solid outer plate, against which the clutch rod pushes, is made of aluminium alloy. Is this normal and is it wise? Thanks
 

Ron L

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My solid outer plate, against which the clutch rod pushes, is made of aluminium alloy.

The clutch rod pushes against the adjuster screw in the clutch spring, which is steel. The clutch spring fingers push against the thick pressure plate which is also steel.

This is a Commando, right?
 
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RGM do an alloy pressure plate, I think it's thicker to reduce lever effort. The rest as you say should be steel.

Cash
 
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Thanks RonL. The clutch rod does, of course, push against the steel adjuster screw in the diaphragm spring cover. However, my outermost main pressure plate is alloy and quite thick, too.
'cash' - I think you are right in that I have probably got an RGM alloy pressure plate, designed for use with fibrous plates and to make the clutch a one finger operation, which mine certainly is.
I was merely wondering if there are other concerns in using a relatively soft material pressure plate, when the other clutch parts are steel / Surflex fibre.
There is evidence of slight grooving on the alloy plate, whereas all other plates are unmarked. Nothing sinister but enough to cause alloy particles to appear in the primary chaincase oil.
 
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May 11, 2007
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In using the thicker pressure plate to reduce lever effort, does this cause a problem with additional clutch drag or no?
 
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I shouldn't think so as you get the same lift.

Scim77
I wonder if you re-arranged the plates to put a steel plate next to the alloy pressure would help? Why not ask RGM.

Cash
 
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I found that I had to turn off the thickness of one steel plate from the thick alum. PP and than fit a steel plate outside to avoid the galling of the alum PP.
 
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Mar 21, 2006
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Sceffy.G - I have no means of comparing whether clutch drag / slip is more likely but my clutch does seem to work well. It is very light yet does not slip, even when provoked. I sense a slight drag when hot, which may be the alloy pressure plate expanding.
I hope to overcome this following the latest suggestions from 'cash' and Norbsa.
Thanks to all.
 
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