clutch friction material

acotrel

acotrel

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Jun 30, 2012
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I have a problem of a slipping clutch in a 1400cc Vincent speedway outfit. It is running 12 to 1 comp. on methanol and the torque is massive. The clutch is a modified item from a Japanese superbike which one would think would handle a lot of torque, however so far we have increased the spring strengths to 60 pounds (?) and it still slips. I'm wondering if carbon compound friction material as used in MotoGP brakes might be better , - the clutch is air cooled. I've heard of guys using a combination of bronze and aluminium plates to get more friction, however I'm puzzled about how that works. We have checked that the pressure plate is not bottoming out
 
I don't know as it is not 'Norton Commando Classic Motorcycles'.
Ta.
 
Wrong forum ?

Talk to the guys that do the clutches for these drift cars. They have very strong engines,
and all the wheel spinning they do, the load on the clutch must be massive.
They could probably point you to someone who does the equivalent for bikes,
but the material will be bonded, so the car guys may be able to do it anyway.

You want to watch that the debris off the clutch will get into the engine oil,
so could be very destructive on engine internals - more like grinding paste than grinding paste ?
Folks that drag race these in top fuel probably also have the clutch figgured out....
 
Sorry about posting to the wrong forum, however I also need an answer for the clutch on my Seeley Commando. I was wondering what friction material would be best in an air-cooled clutch ?
 
acotrel said:
Sorry about posting to the wrong forum, however I also need an answer for the clutch on my Seeley Commando. I was wondering what friction material would be best in an air-cooled clutch ?
Click to expand...

The Commando clutch topic is well covered by a current thread in the Commando forum.

Barnet fibre plates are light and effective, so would be good in a racer. The RGM supplied bronze 'high torque' plates have had the thumbs up from Comnoz in his own tuned bike. They are more expensive than the a enters though.
 
Are you talking about the amount of 'throw' ? Or the friction limit ? I think the clutch is a Barnett with the plates used for a 1000cc superbike, so should be adequate. And there is nothing preventing full spring pressure being applied to the plates. Are Jim Comstock's bronze plates used in place of the bonded compound ones in conjunction with steel?
 
acotrel said:
Are you talking about the amount of 'throw' ? Or the friction limit ? I think the clutch is a Barnett with the plates used for a 1000cc superbike, so should be adequate. And there is nothing preventing full spring pressure being applied to the plates. Are Jim Comstock's bronze plates used in place of the bonded compound ones in conjunction with steel?
Click to expand...

Yes. See RGM website.
 
Thanks for that, Eddie. I saw the photos of the bronze commando plates, I don't think RGM have them for the dominator type clutch and I was wondering how they make them.
 
acotrel said:
Thanks for that, Eddie. I saw the photos of the bronze commando plates, I don't think RGM have them for the dominator type clutch and I was wondering how they make them.
Click to expand...

Have you asked RGM if they can supply them for domi?
 
No I haven't. Judging by the commando plates they are too expensive at about 20 pounds each and the complete set is about 500 pounds. Looking at the photos, the shape of the contact surfaces where the grip occurs, they look similar to ordinary bonded plates. I was simply sounding out if anyone knows how they are made. I suspect CNC, however I doubt that they need to be so elaborate.
http://www.rgmmotors.co.uk/images/full/full_158.jpg
 
acotrel said:
No I haven't. Judging by the commando plates they are too expensive at about 20 pounds each and the complete set is about 500 pounds. Looking at the photos, the shape of the contact surfaces where the grip occurs, they look similar to ordinary bonded plates. I was simply sounding out if anyone knows how they are made. I suspect CNC, however I doubt that they need to be so elaborate.
http://www.rgmmotors.co.uk/images/full/full_158.jpg
Click to expand...

They list a kit to convert a Commando clutch at £120.

With RGM, it is important to remember that they do not list all items on the web site.

A call, or email will quickly ascertain if they stock these for pre Commando or can modify Commando items to suit.
 
acotrel said:
No I haven't. Judging by the commando plates they are too expensive at about 20 pounds each and the complete set is about 500 pounds. Looking at the photos, the shape of the contact surfaces where the grip occurs, they look similar to ordinary bonded plates. I was simply sounding out if anyone knows how they are made. I suspect CNC, however I doubt that they need to be so elaborate.
http://www.rgmmotors.co.uk/images/full/full_158.jpg
Click to expand...

or you could try a 5 spring Jawa grasstrack clutch, these can be obtained to fit on to the Norton gearshaft.
NEB Speedway Grasstrack website;

http://www.ebay.co.uk/itm/SPEEDWAY-Gras ... 419883a9e2

Please note, with this "With your order, please specify what type of clutch springs (soft or hard) you would like!"
 
I have one of Bob Newby's dry clutches in the 1360. He normally makes them with five plates but wisely decided to make this one with seven plates. You then tension the springs as needed to do the job. I started with a nice light clutch action but that slipped. After a couple of trials and adding spring tension, the slippage stopped, but the lever pull is fairly stiff.
Holding back 1400 ccs on alcohol would be formidable.

Glen
 
Bernhard said:
acotrel said:
No I haven't. Judging by the commando plates they are too expensive at about 20 pounds each and the complete set is about 500 pounds. Looking at the photos, the shape of the contact surfaces where the grip occurs, they look similar to ordinary bonded plates. I was simply sounding out if anyone knows how they are made. I suspect CNC, however I doubt that they need to be so elaborate.
http://www.rgmmotors.co.uk/images/full/full_158.jpg
Click to expand...

or you could try a 5 spring Jawa grasstrack clutch, these can be obtained to fit on to the Norton gearshaft.
NEB Speedway Grasstrack website;

http://www.ebay.co.uk/itm/SPEEDWAY-Gras ... 419883a9e2

Please note, with this "With your order, please specify what type of clutch springs (soft or hard) you would like!"
Click to expand...

p. S. I have just noticed that they do not come with a centre adjuster and locknut-whether you can drill and tap a hole for one to be honest I don’t know, anybody ever tried :?:
 
worntorn said:
I have one of Bob Newby's dry clutches in the 1360. He normally makes them with five plates but wisely decided to make this one with seven plates. You then tension the springs as needed to do the job. I started with a nice light clutch action but that slipped. After a couple of trials and adding spring tension, the slippage stopped, but the lever pull is fairly stiff.
Holding back 1400 ccs on alcohol would be formidable. Glen
Click to expand...

Perhaps you all really need a servo clutch, it fits into the normal Norton clutch-there was a handful made in the 1960s Heinz Kegler repatriated these from Birmingham when Norton moved to Plumstead, it has a 17 degrees angle where the plates locate-this locks up the clutch on take off, but will allow it to slip on early change down, preventing the rear wheel from locking up-simple :!:

search.php?t=7577

( Later on, I installed more improvements, heavier connecting rods, double speed oil pump with pressure feed to the rocker arms, better crank case ventilation, very light flywheel, servo-clutch,
the above -from H.Kegler.
Also;
who-would-buy-one-these-amc-gearbox-clutch-centers-t12429-15.html?hilit=heinz%20kegler%20clutch#p146154
 
Interesting clutch but in reading further it did not stand up to use in a Commando with 48-56 ft lbs torque (don't know it the test mule was a 750 or 850) so I don't think it would live long with 115 ft pounds going through it, even if it could resist slippage.
My 7 plate Newby dry clutch works very well, smooth to operate, no drag, no slippage, but spring pressure must be set fairly high. Even at that it isn't nearly as difficult to pull in as my stock 850 Commando clutch was for years before I finally shimmed it properly.
Just not a one finger pull like the Commando clutch is now.
Maybe a candidate for a hydraulic clutch actuator like Jim builds for the Commandos.
Oh, but that would add a few ounces of weight, forget it!

Glen
 
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