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things that may prevent clutch adjustment

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  • things that may prevent clutch adjustment

    How about a list of wear items that may affect successful clutch adjustment,
    Here are a couple to start with
    1. warped clutch plates
    2, Clutch throwout bearing-especially the 16 ball bearing type.
    I know there are a number of less obvious contributors to this issue.

  • #2
    Aha!... where shall we start! (just kidding).
    One of the traps with this clutch is that over the many years it was produced, many minor changes were made to various components, and it's quite easy to assemble one with wrong components without realising it. There's an extensive chart of clutch parts, measurements, models in Norm's Technicalities. (I might scan it and put it up here if it'd help).

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    • #3
      Yep ...it WILL help !!

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      • #4
        As promised. All credit to Norm Trigg, author of 'Norm's Technicalities', and thanks to the Australian Velocette Owner's Club for the hard copy source for scanning.

        Last edited by joolstacho; 01-19-2020, 10:19 PM.

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        • #5
          And another thing... One of the best upgrades to a Velo clutch is to convert from ball bearings to roller bearings in the thrust race. There's BIG point-load from the bearings balls*, but rollers spread the load really well. I think you can buy ready converted roller races, but if you've got more time than money you can DIY by just filing every one of those round ball holes in the bronze part. (Enjoy!) File 'em square to suit the rollers you bought. I think they're 3/16"x3/16" but I need to check so don't 'quote me'!
          *One of the reasons riding the clutch at the lights is an absolute no-no with a Velo.
          Last edited by joolstacho; 01-19-2020, 09:56 AM.

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          • #6
            Hidden trap for new players, the felt ring that 'seals' the inner lift plate against the primary cover must be the exact correct thickness or the clutch won't fully disengage.

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            • #7
              As my clutch is currently in a box awaiting progress on the project build I can lay the parts out and look them over .... the clutch has been " modified " by Ed Gilkison ....not sure what the modification is.
              What is the " exact correct thickness" of the felt ring seal ?..... does it need to be compressed ala Norton Commando primary felt seal ?.

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              • #8
                I can't recall offhand but I'll check later when I have access to the relevant material. However, if the felt is obtained from the Spares Company or one of the other principle spares suppliers, it will be correct. The problem is when previous owners have tried to improvise with something at hand, that they thought was 'was near enough'! Then, subsequent owners try to work out why their clutch won't adjust properly!

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                • #9
                  Thanks Singlething ..... I will be getting the parts that I need from either .... Grove or Spares Company, and perhaps, Ed Gilkison .... Velocette guru in the USA.

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                  • #10
                    Just saw this thread... but how about the question I popped in here?
                    https://velocette.vbulletin.net/foru...-12-series-box
                    Selector rod, (the one located behind the thrust pad for the frying pan, ) being pushed too far in when fitting the gearbox end cover.... lifting the thrust pad out of position....
                    Food for thought... hard to diagnose without removing chaincases.

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                    • #11
                      couple more- Not only have the correct clutch lever (1 1/8" nipple centre to pivot centre, but also make sure the pivot hole in the handlebar clamp (perch) is not worn and elongated.
                      They can be reclaimed by filing round and reaming to 3/8 dia then make up a floating bronze bush with a 1/4 ID.
                      Also be wary of fitting big fat handlebar grips-they limit the clutch lift.

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                      • #12
                        Interesting you should mention that, one of my machines is an MV Agusta 750 Brutale that I bought used. It is in pristine condition with just a few small mods, one of which was aftermarket adjustable reach handlebar levers. I checked them out and they are a quality item and all seemed good. As ever with a new machine, one has to settle into it and discover all the quirks and jinks etc.
                        The bike rode really well but I did notice the gearbox was a bit notchy and I occasionally missed a gear and it sometimes jumped gears when releasing the clutch. So I started to work through the possible culprits. It's a hydraulic clutch so I checked for air, adjustment etc, but all seemed ok. So as the clutch lever was non standard I checked that out and the problem became apparent. The lever was set to move the lever back to the grip, I suppose for a more convenient reach for the previous owner, problem was, it reduced the lever travel and consequently did not allow the clutch to fully release! I had to adjust it fully out to prevent any reduction in lever travel, the gearbox has been perfect ever since! I just hope non of the dogs have been nibbled by the problem.

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                        • #13
                          I wonder if wear on the main gearbox bearing ( or a sloppy fit of the bearing in the gearbox shell ) could deflect thus reducing clutch lift?

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                          • #14
                            If the play was lateral I don't think it would noticably affect clutch operation, but if it were axial then it could. I think by then though other issues might be apparent!

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                            • #15
                              Thrust pin and operating lever wear? Chainwheel bearing? Chainwheel / engine sprocket alignment? - Plenty more potential problem areas - what fun!

                              I've just been 'revising' 'Norm's Technicalities' on this subject, and there are pages and pages of good information there (just on the clutch alone - and it also covers everything). I don't feel so comfortable reproducing complete sections out of the book (I have my Guru's blessing to quote and use small sections from it, because he wrote/compiled it, but the Aussie Club has an 'interest' too, as they publish it. Anyway as far as I'm aware, copyright is a bit rubbery!
                              All I can do is encourage everyone to buy it. 'Norm's Technicalities' It's so cheap, and SO stuffed with technical gems it's madness not to have a copy. If you can't get it via your local club, let me know, I could probably organise it from here.

                              At one point someone was producing a 'proper' lipped rubber seal to replace the felt, which has a proclivity to bunch up and restrict plate movement.
                              Confirming those rollers for thrust roller bearing conversion ARE 3/16" x 3/16".

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