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Surflex Clutch Plate – Is there a problem?

Home Forums TR3OC Members Forum Surflex Clutch Plate – Is there a problem?

This topic contains 6 replies, has 5 voices, and was last updated by  james lucas 1 week, 5 days ago.

  • Author
  • #9383

    james lucas

    Sorry chaps – second attempt. Following the replacement of a new clutch on my T150v this year the operation has been, to say the least ,”heavy” to the extent that it has pulled the nipple off the cable. I went to Beezump this year and sampled enough clutch levers to realise that mine was definitely not right.

    Following the article in the TE 242 page 59 by Clive Blake this prompted me to examine the clutch assembly. I took the clutch to Richard Darby who had kindly offered to examine it. Using the paper finger test the pressure was up to 40 thou with little sign of release of the fingers. The clutch was examined and it was found that the rivets on the Surflex clutch plate had been in touch with the fingers on the pressure plate. See photographs.

    Richard examined other pressure plates in his possession and found that the fingers on the pressure plate has been machined to allow a recess. see photo. Was this a problem identified by Triumph?

    Any comments or observations on why i have had this problem on my clutch would be appreciated. Thanks James20191115_13001720191112_13152120191112_111027

  • #9417

    Angus McLeod

    I don’t think Triumph would ever have fitted a clutch like that, but I could be wrong. I’ve only ever used the original type and never had a problem. I had one relined after 90,000 miles. I also sprinted a class winning bike with a standard plate  without issue. It did have a stronger spring though.

  • #9428

    Clive Blake

    If you want to discuss, give me a call tomorrow evening on 07802965092.


  • #9432
    David Patterson
    David Patterson

    Good information, thanks for posting.
    I just put a Surflex plate in my clutch. It passed the paper test on the bench but I haven’t ridden the bike yet. I’ll report back if there’s any trouble.

  • #9437

    nigel wheatley

    The ‘problem’ is that it seems as if triples were fitted with 2 variations of the clutch pressure plate, although as far as i know the part number (57-3715)  never changed. Clutch assemblies came already built up by AP in leamington who also made the very similar BMC Mini clutches so it’s possible that BSA/Triumph were unaware of the variation.

    You can see the variation in the 2nd and 3rd photos that James has posted above. In the 3rd picture you can see a flat is machined in the each of the 4 webs that support the plate, the flat is about 11/16 or 18mm wide. In the 2nd picture the pressure plate has no machined flats.  Both examples are original un-modified/standard clutch pressure plates

    The ‘problem’ arises because the Surflex replacement clutch driven plate comes with rivets that stick out/proud when compared with the AP original. If you have a clutch pressure plate that is without the machined flats, then the rivets on the Surflex plate can catch and drag on the supporting webs of the pressure plate and that will create a clutch drag as it will impossible to seperate the two components cleanly. If you have the pressure plate with machined flats then there is no problem as the flats give enough clearance for the rivets on the  Surflex plate

    We must assume that when Surflex began making replacements, they were using a pressure plate that had machined flats and weren’t aware of any without the flats. The original and unavailable AP clutch plates came with rivets that were/are flatter/flush with the plate and which will clear the un-machined pressure plate in James’s 2nd picture.

    So why did AP start supplying clutch pressure plates with flats machined in them? Who knows? but could it be linked to the developments in BMC Mini and the aftermarket in car parts if Mini clutches were being reconditioned with new friction material then there would presumably need to be more clearance for new rivets?

  • #9438

    Clive Blake

    I have in my workshop 5 late  (Small Heath) T150V T160 clutches, although the pressure plates don’t have machined flats on them they all clear the rivets on a standard Surflex clutch plate, I do as a matter of course now machine 0.050″ from the rivets as they could contact the pressure plate webs when worn.

  • #9456

    james lucas

    This is an update on the problem solving the Surflex clutch plate . In my initial post you will note from photo 1 and photo 2 there is evidence of the rivets on the friction plate coming into contact with the webs on the pressure plate. thus preventing a separation between the two. I have had the webs machined to provide additional clearance and this overcame the problem between the rivets and the  pressure plate. Equally I could ,as Clive Blake suggests, machined the rivets to provide the clearance which i may still do to ensure sufficient clearance at the friction  surface wares down.

    Having reassembled the complete clutch using the paper finger test i can now release the paper fingers at 23″ which must make an improvement to the clutch operation . It is worthy of mention that the placement of the pressure spring has to be placed in numerous locations to get the best clearance, it took me six attempts to find the best location but i feel it was worth it. Hopefully my patience will provide a lighter and a non dragging clutch. Thanks to those who have contributed  to this post. James

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