Restoring magneto on Allen Scythe, Villiers 25c

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This topic contains 5 replies, has 3 voices, and was last updated by  andyfrost 1 month, 1 week ago.

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  • #38144

    rowan-bradley
    Participant

    I have removed and dismantled the magneto. Now I need to decide what bits to replace. I am loath to spend money replacing bits that are still good.
    1. I have measured the resistance of the coil, the primary seems to measure about 0.5 ohms. Is this likely to be correct, or does it suggest a short somewhere? The secondary seems to measure about 2.72K. Is this likely to be correct? Is there any other way to test the coil and verify whether or not it is faulty?
    2. How can I test the condenser, or do I just assume that it is 50 or more years old and needs to be replaced anyway?
    3. I can try cleaning the points, and if I can get a good metal surface on each side, I assume that they will work.
    4. There is what looks like a spring loaded felt pad on the opposite side of the shaft from the contact breaker. I suppose this is for lubrication. Do I need to clean it and soak it in oil? What sort of oil?
    5. There is a very flimsy spring at the end of the HT lead that is I suppose meant to keep the contact touching the contact on the side of the coil. This spring is seriously messed up on mine. Can anyone sell me a new one? Or recommend a way of replacing this that will work (for 50 years)? If I buy a replacement HT lead from villiersparts.co.uk, does this come with the spring?
    6. The cam that operates the contact breaker looks suspicious to me. It seems to consist of a sleeve (or half a sleeve) that half surrounds the shaft (see picture, sharpish edge ringed in red). The beginning and end of this sleeve look pretty abrupt, which would I would have thought put a lot of strain on the moving contact of the contact breaker. Is this what it’s meant to be like, or is something missing from this?

    Thank you – Rowan

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    #38147

    rowan-bradley
    Participant

    One more question:

    7. My magneto has no cover over the round compartment containing the contact breaker. I don’t know whether it never had one, or whether a previous owner lost it. The spring clip that is designed to retain the cover in place is there. Do I need to find one or make one? Does any one sell these?

    Thank you – Rowan

    #38148

    andyfrost
    Participant

    Only my opinion , but I would NEVER skimp when it comes to magneto components , it’s worth every penny to renew all the components , it will give you effortless starting every time.
    Forget about testing with a multimeter , there is a very good reason why purpose built ignition testers were made.
    George at villiersparts used to do the complete kit for the 25c , he may still do , either way he would be able to supply all the parts that you’ll need.
    The cam that you refer to is the “electronic govenor” , if you tease it GENTLY with a suitable screwdriver you should be able to just open it , if it’s opening and closing OK , then simply leave it alone.

    Andy

    #38150

    charlie
    Keymaster

    I agree 100% with what Andy has said regarding replacing everything in the magneto, money well spent. New coil, condenser and points along with a new HT lead. I did this on the Villiers MK25 four stroke engine on my Trusty Earthquake, starts with no problems.
    The little cover for the points often gets lost (thrown away).

    #38153

    rowan-bradley
    Participant

    What is the best thing to do about the spring loaded felt pad, which I suppose is designed to lubricate the contact breaker cam? Can I restore the old one in some way (soak it in petrol, or wash it?)? Or do I need to buy a new one (Villiersparts have them)? Presumably it needs to be soaked in oil? What sort of oil?

    Thank you – Rowan

    #38155

    andyfrost
    Participant

    If the felt is still intact , simply wash it in petrol , dry it thoroughly and put a couple of drops of engine oil on it , squeaze gently between thumb and forefinger…….job done.

    Andy.

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