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1960 24TCS Scottish, one of the two barn finds

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  • 1960 24TCS Scottish, one of the two barn finds

    For background, please see the previous thread on the two barn finds. To recap, the engine has a Vale-Onslow aftermarket barrel, and unknown, possibly a Hogan head. They appear to be more scrambles than trials items. It is fitted with a 26mm Concentric, which is rather small for the manifold.The bore is at + 0.020", with no apparent wear. I have yet to check the rings in the bores. The piston is very different to the Villers one, the crown to gudgeon pin being much closer on the VO piston than the Villiers; see pic.

    Having removed the head and barrel, I was pleased to find an Alpha full-circle crank, with no apparent big end play, and crank running smoothly in the main bearings. I think it has a 5 1/4" rod, but will have to remove the piston in order to get a more accurate measurement.

    Removing the points cover revealed nothing! No points assembly, and the inner casing cut away. Removing the casing revealed more of a surprise, as the flywheel was not a Villiers one, with an outer plate held in place by 4x counter-sunk allen screws. A shiny set of points were visible behind the flywheel, accessed by slots in the flywheel. I undid the screws, but they won't come out, presumably retained by nuts, so the outer plate will not come off. I shifted the centre nut with my Villiers Hammer-tight tool, but the nut just spun off; so not an extractor nut then! This leaves the dilemma of how to remove the flywheel?

    Does anyone recognise this set-up, and can say the best method for flywheel removal? All info gratefully received. See pics.....

    I think this engine has not revealed all it's secrets yet!

    tbc
    Attached Files

  • #2
    Is there a female thread in the recess where the flywheel not fits? If so you need a threaded extractor that fits that thread

    Comment


    • #3
      You are correct John. It was in a rather gloomy corner of my workshop when I removed the timing cover. Having wheeled it out in the sunshine the thread became apparent. I have 4 of those pullers; the largest being not quite big enough! With the 4 screws loosened, a few taps around the periphery soon loosened the flywheel, but it is the plate on the outside, which contains the thread, which does not want to shift. I will ask around to see if I can find a suitable puller. I need to remove it to see what is inside, but specifically to change the crankshaft oil seal.

      Thanks. Ian

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      • #4
        Ian I have asked around and It looks like a Bosch one as fitted to the Cotton Javelins if so it has an internal points cam with advance Bob weights
        If you have not already done so its not advisable to separate the two parts, if you do then make sure they go together in same location (Balance and position of magnets for maximum flux!)
        Last edited by John Wakefield; 10/05/2019, 05:04 PM.

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        • #5
          Thanks for that John. That is interesting. One wonders what the perceived benefit was, back in the day? The bob-weights giving auto advance for better starting, perhaps? I have tightened the plate back up, in order to remove them together. Just need to finds a puller!

          Comment


          • #6
            The Cotton Javelin had the DMW engine https://cottonownersclub.wordpress.c...minerelli-era/ it was their final trials bike. If it is Bosch then there should be some evidence of that.
            DMW was bought out by Metal Profile see http://www.historywebsite.co.uk/Muse...lateryears.htm
            Last edited by John Wakefield; 10/05/2019, 09:35 PM.

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            • #7
              I am aware of the Cotton Cougar, Telstar & Conquest, but am not familiar with the Cotton Javelin. Was that the last Cotton trials model before they started using Minarelli engines? Anything to do with Fluff Brown, post Villiers, when he took over the AJS 2-stroke competition models? They were Starmaker based engines though.

              Comment


              • #8
                No nothing to do with Fluff Brown but Pat Onions and Terry Wilson, it was made at same time as Minarelli. Its all on the Minarelli DMW link I posted https://cottonownersclub.wordpress.c...minerelli-era/

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                • #9
                  Ah, I missed that post, John. It may have gone up while I was typing mine. Interesting stuff. The set-up does appear to be as you say, and I can just see a bob-weight device through a slot in the flywheel. No sign of any Bosch markings, or any markings visible, at least while the flywheel is still on. If it is Bosch, the puller is likely to be a metric thread. It measures 30mm diameter inside the threads, which appear to 1.25mm pitch, a thread gauge of that size fitting nicely. Now to find one.....

                  Thanks
                  Ian

                  Comment


                  • #10
                    Its strange that this flywheel mag has not come to light previously as I am sure there must be a few about. Presumably DMW had to find another source after Villiers stopped making (and selling to third party's) the 36A engine.

                    This company does a wide range of extractors but none near 30mm od with 1,25 thread, are you sure its not 1.5mm pitch https://www.motorcycleproducts.co.uk...c-918_834.html
                    Last edited by John Wakefield; 11/05/2019, 10:12 AM.

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                    • #11
                      Yes, I figured that was the reason. It was a 1970's mod then, obviously? I can't imagine DMW actually made that many of them.Presumably some of these models are still around, so the pullers must be available somewhere. Likewise I doubt they were specially made by Bosch for them in small numbers, so one wonders what the original fitment would be?

                      Annoying about that puller. It is definitely 30mm x 1.25mm right-hand thread. I may contact the company on Monday anyway. Well spotted.

                      Comment


                      • #12
                        I took the whole crank assembly to a local engineering company who have done a lot of work for me in the past, in order for them to make me up a flywheel puller. Collected it today, having spent the last week on my Moto Guzzi in Brittany. Turns out the thread in the flywheel wasn't definitely a 30mm x 1.25mm thread! It is Imperial; 1 1/4" x 20tpi.

                        With flywheel successfully removed this afternoon, with lots of resistance from the magnets, there are no signs of any makers name, or any markings. Does anyone recognise this assembly? You can see the inside of the rotor, clearly showing the auto A/R setup. The stator plate has 2 coils, the top one the ignition coil, presumably the bottom one, with 2 yellow wires, is a lighting coil. The 2 wires are taped up as no lights are fitted. The points look sound, but what points they use I don't know. Anyone recognise them? To the right of the crankshaft and left of the capacitor you can see a threaded boss on the stator plate. Nothing in it. Must be there for a reason. Any ideas? Although the bottom end feels sound, I will be splitting the crankcases having got this far, and will get them vapour blasted, check bearings, new seals etc.

                        There was a circlip hanging on to one of the magnets which warrants a further look.

                        Ian
                        Attached Files

                        Comment


                        • #13
                          Not sure but this looks like (as previously suggested) a Bosch sytem modified to fit a Villiers engine. The original Bosch pressed steel flywheel appears to have been shrunk into a larger heavier steel flywheel presumably to give a heavier flywheel for the Villiers set up. The Bosch system is probably from a smaller capacity engine, maybe a 125cc Sachs or Puch
                          So a bespoke set up made by DMW. Looks like you need to track down Pat Onions or Terry Wilson (if they are still alive!)
                          Last edited by John Wakefield; 28/05/2019, 07:32 PM.

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                          • #14
                            Thanks John. You would think there would be some reference to Bosch on there somewhere, wouldn't you? Also, why are they using Imperial threads? I can't see them being made by Bosch to DMW's specification. The order just wouldn't be big enough. Someone must have seen one of these, surely?

                            What do you reckon about the little threaded lug with nothing in it?

                            Comment


                            • #15
                              Yes surprising that the Bosch name is not on some of the parts, of course it could be from another continental maker Minarelli maybe!, DMW just bought standard parts and adapted them to fit the Villiers engine, clearly the Bosch? flywheel was inserted & bolted into a large (and heavier) steel flywheel. Presumably DMW had these machined by a local machine shop. I dont know how many of the Javelin bikes were made, only a handful I would think. Is the thread for extractor on the inner flywheel or the outer one? If the latter it would explain why its Imperial thread not metric having been made in the UK.
                              As for the threaded boss, no idea, a clip to hold the capacitor, or an earthing point for coils maybe! If you cant get contact with Onions or Wilson you could try John Harding, as it was he who told me the set up was from the DMW Javelin.
                              Last edited by John Wakefield; 29/05/2019, 11:04 AM.

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