Surflex Clutch Plate Source?

I had a set of Surflex bonded friction plates in my '70 Fastback and they worked great - never slipped, light action, never a clunk going from neutral to first, and never a problem going from first to neutral. Presently my '75 Mk III is fitted with the OEM bronze plates with a clutch rod seal and they work OK but with a bit of drag (hard to find neutral at stoplights). I'd like to fit it with a set of Sureflex bonded friction plates, but I can't seem to find a supplier. No joy in searching the list - much discussion on clutches but no suppliers found. Any leads appreciated, especially US suppliers.

Thanks for your time,

Joe in St Louis

Joe,
Any Norton dealer- part# 06-0749 from Andover Norton.
Joe

Joe from St.Louis,
Saw your question sent on to me but have no idea how to answer it, so use this forum.
06-0749 was the very early bonded plate used on the first Commandos- this is the steel plate with friction material (Triumph style). These plates were later replaced with the lighter "fibre" clutch plates 06-1339, which is more common in the spares game now and general use in vintage racing because they are lighter. The late "sinter" plates 06-3741 were changed together with the end plate (originally the 06-0745, which needs to be changed to the thinner 06-3768 when you use the "sinter" plates).
The "sinter" clutch uses 1 more of each plate, i.e. 5 friction plates and one more steel plate than the earlier versions. This package is thicker than the earlier pack even though the 06-3741s are thinner than the 06-0749 resp. 06-1339. As the diaphragm spring has a limited operational range, and can not be pre-loaded in the way a conventional spring can, the pack thickness has to allow for that, hence the necessity for the thinner end plate.
So if you want to change to the earlier plate setup you can discard of one steel plate but have to get the thinner end plate. Both clutches work; I checked involuntarily when my son Tim, then proud owner of a 125cc 30+bhp Aprilia, wanted to show Dad how to accellerate from a standing start in the paddock, let the clutch slip endlessly (as on the 125), and cooked the fibre plates. I had a sinter clutch with me just in case, so we switched to that, and it worked equally well. We use the standart chaincase with oil & primary chain. I never ever had a primary chain fail, but I have seen many a race bike coast to a stop with a toothless belt. I fill it with Shell Donax TX automatic gearbox oil instead of multigrades, most of which get the clutch to simultaneously drag and slip. No problems with slipping or sticking clutches in 10 seasons of Commando racing, with markedly more power and torque than a standart Commando has.
Joe Seifert

Joe,
Sorry I did not include my email address in my previous private message - thought it would show up automatically at your end.

Thanks for your explanation of the evolution of Commando clutch plates. I was not aware of the early bonded steel plates used in Commandos. I was under the impression that there were only 2 types; the thick solid fiber plate (4 ea used with thick [06-0745] pressure plate), and the thin sintered bronze plate (5 ea used with the thin [06-3768] pressure plate). The Surflex clutch pack I had in my '70 Fastback was not the original equipment, but rather a replacement recommended by a pal. As I recall the Surflex plates were constructed of a friction material bonded to a steel plate. They were much thinner than the original solid fiber plates, closer to the thickness of a sintered bronse plate. I'm embarresed to admit that I don't recall if my Surflex clutch pack in the Fastback was set up with 4 or 5 friction plates. I seem to recall using the thin pressure plate and perhaps an extra plain steel plate to get the diaphragm in it's sweet spot, so the clutch pack probably consisted of 4 friction plates, 4 plain steel plates, and a thin pressure plate. What I do remember is that my clutch performed flawlessly - easy pull, always complete & total release, never a klunk going into gear from a stop (chain didn't even snatch), the shift from 1st to neutral was the same as if the engine weren't running, and it never slipped, even with high RPM shifts.

Since I am not familiar with Triumph clutch plates, could you please elaborate on the 06-0749 that you provide these days. Are they NOS items from early Commando production or are they new items supplied by Surflex? Is the friction material bonded to steel or aluminum plates? Could you provide the nominal thickness of the 06-0749 plate?

All this may be a moot point now. Over this past weekend I replaced the lube in my Mk III's primary. After draining the old lube I reinstalled the drain plug , poured 12 oz or so of mineral spirits into the primary and ran the engine for a few moments on the workstand. The engine was shut down, the spirits drained, and the process was repeated, this time actuating the clutch a few times and putting the machine in gear while holding the rear brake on. The second batch of spirits was drained and 7 oz of ATF was added. Since doing this procedure the clutch seems to be working much better. I was not experiencing slippage before but it was very difficult to find neutral while stopped at a traffic light. I've gotten into the habit of finding neutral while coasting to a stop, but sometimes I do forget and all seems better now.

Thank you and all the members of this board for your patience. I would appreciate the details on the Surflex (06-0749) plate when you find the time.

V/r

Joe in St Louis

ZFD said:

Saw your question sent on to me but have no idea how to answer it, so use this forum.

Click to expand...

To reply to a private message, click the "SENDREPLY" button above the message, type the reply, and click "Submit".

Interesting to know about the clutch plate history. I was not aware the Surflex plates were available from AN. My favorite supplier does not seem to carry them. I bought a set from Norvil that I put in my 850. My 750 has the solid fibre plates, still working perfectly with no issues.

Debby

Dear Joe in St.Louis,
06-0749 are made by Surflex for us (Andover Norton) and are steel plates with friction material bonded to them, similar but not identical to the friction plates they do for Triumphs. Thickness of 06-0749 bonded and 06-1339 fibre is identical. Few people use the bonded ones these days, and I (Norton Motors GmbH in Germany) stock them mainly for one dealer who has quantities of them regularly. Andover Norton carry them which is my source, surprise, surprise....... I carry the Surflex Triumph plates too, which are far better quality than the Chinese offerings (EMGO) often sold as "Made in England".
Joe Seifert