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Belt drive conversion 37A

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  • Belt drive conversion 37A

    I found this on belt drives from the Villiers Improvements Handbook
    In the light of modern day technology a change to belt drive is possible, but no volume manufacturer produces one this small, in commercial quantities. Nortons and Triumphs are well catered for, so why not the Villiers. Brian Wolley commissioned Tony Hayward to build a belt drive system for his Silverstone Mk 2 some years ago, but this engine and clutch were of Greeves manufacture and the gearbox by Albion. The belt used was of 1 inch polypropylene and said to be able to transmit 50 bhp.

    Fortunately, a belt drive is available new from Igor Ashwell for the 9E, which he uses on his own kart, to good affect. The system uses a 30 mm belt, which retains the standard primary drive ratio, and the original Villiers clutch basket rivetted to a new pulley (where the new pulley replaces the original sprocket). The clutch runs cooler in the open air and does not slip, even though he only uses 3 friction plates, and the standard 9 spring centre and plates.


    Igor Ashwell has since died so I dont know if anyone else has taken on the belt drive, maybe Nametab Engineering or one of the Karting specialists. If it can be done for Villiers I would have though it possible for the Griffon.
    Last edited by John Wakefield; 18/08/2017, 11:09 PM.

  • #2
    Just thought I would bump this thread which John started a few years ago, as a belt primary drive seems a good way to overcome the inherent weakness of the single run primary chain on our 9E-through-37A motors.

    There was no mention in the Carrick/Wood book of how Igor came about this conversion, whether it was a one-off etc. Rivetting the large pulley onto an existing clutch basket would massively strengthen the basket, it then just needing a crankshaft pulley and 30mm belt; oh, and a wider primary chaincase.

    I wonder if a trawl through existing systems may turn up compatible or adaptable components?

    Any ideas, anyone?

    Ian

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    • #3
      Belt drive

      Rivetting a belt drive pulley to a Villiers clutch basket would be an obvious way to create a basic belt drive.

      In reality it would be more beneficial to machine a new pulley combination incorporating a modern all aluminium clutch. The limitation I believe is the availability of the belts.

      Pretty certain Peter Inchley had a belt drive on his Starmaker engine.

      As an alternative I have seen gear primary drives.
      Last edited by Phil Hyde; 16/08/2017, 11:03 AM. Reason: More worms and spellinn

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      • #4
        From Villiers info

        "so here is a belt drive version of the CNC copy of the Griffon clutch by Nametab Engineering, fitted to the engine to be paraded"

        Maybe Simon knows the answer?

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        • #5
          Nice one Tony

          I must keep up with the 'scene'. Further down in the same article is a slight variation of belt and crankshaft pulley

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          • #6
            I have e-mailed Simon, so will wait to see what he comes back with.

            Another benefit would be if a slipper tensioner could be incorporated, to save having to remove engine and gearbox just to tension the belt.

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            • #7
              Simon does make one for VS, but aimed at karts. It won't have an extended chaincase, and VS seem reluctant to recommend them for trials/road/ scramblers. Couldn't get at a price or spec., so, unless it is for a kart or Silverstone, probably not worth bothering with.

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              • #8
                If it works on a Kart would that not get more of a thrashing than most trials/ road bikes? I cannot understand why it would not be suitable

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                • #9
                  The conversation with Steve at VS was rather, let's say, negative about the whole concept. The usual thing, on the basis that he and many others have regularly trialled, and scrambled, over many years, and never come across the need for a belt drive. They have robust chains, chain tensioners etc available, so why? he asks....

                  There is an issue, to be fair, in that they are wider, when you want a trials bike to be narrow, hence the swap from the standard Villiers p/chaincase to the minicar one. A spacer would be required to accommodate the wider belt. With karts, they tend to be run with no chaincase and a minimal sheet ali top chainguard. Trials, scramblers, roadsters all need full enclosure.
                  Hence they have only, apparently, seen use on karts and road racers.

                  I am just reporting what he said, and believe me, by the end of the conversation, in fact well before the end, I wish I had never asked, having had to listen to forums, and those who go on them, being slagged off, on the basis of 'there are those who do, and those who talk about' kind of thing. It wore me out.....

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                  • #10
                    Belt drive

                    You would probably have a different answer if they sold a kit !

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                    • #11
                      Probably needs to sell more of his chain tensioners

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                      • #12
                        They do sell a kit. Simon Bateman makes them, but he does not retail anymore, and sells them to VS. He supplied them with 10 recently. As they are ostensibly for karts, Steve has a karting mate who takes them to kart meetings, flogs them and earns an extra shilling for doing it. That is why he does not show them on the website, as the supply is small, and he doesn't want to undercut this other bloke. Having said that, he did say that he would sell me one if I wanted one. Trouble is he wouldn't give a price, he said he has all the components on the shelf, and makes up what people want, but it was put in such a way that he really didn't want to, by which time I was losing the will to live.....

                        I have decided that I don't want one anymore!

                        See if you can prise one out of him!

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                        • #13
                          Ian
                          Have you looked an any Karting websites or forums, if Simon Bateman can make them so can any competent engineering concern. I would think they are a well known conversion in karting and there may be other suppliers.
                          Here is the article in full from the Villiers Improvement book http://www.villiers.info/VSIH/VSIH3_sample_ch6.pdf
                          Last edited by John Wakefield; 18/08/2017, 11:10 PM.

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                          • #14
                            John. Thanks for that. I do have the book, although the 1st edition, not the 3rd, as you have. The article is much the same, though.

                            I do actually now think that it may be more trouble and expense than it is worth, apart from in a Silverstone. I don't know anything about karts.

                            Out of interest though, it may be worth looking at kart sites, to see what they do.

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                            • #15
                              The man to have asked about this was Igor Ashwell, but as he died a few years ago thats not possible unless you know of a good spiritual medium
                              Personally I cant see why if its ok for karts & Silverstone's giving out around 30 bhp that its not OK for a road bike giving the standard 12 to 17 bhp
                              After all if the belt breaks its easy to fit a new one, you could do that at the roadside assuming you carry a spare. Harley Davidsons & indeed the 'modern' Morgan 3 wheeler use belt rear drives. Seems like Simon Bateman/Villiers Services are missing a sales opportunity here.

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