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Cyclemotor spares

by Brian Smith

The hobby of "clip on" restoration, by which I mean perhaps the major activity, is still a relatively cheap and easy one for the DIY man.  Except for rare models it is still mostly a home job combined with many visits to autojumbles.  The fact that most of these "clip on" engines were bought as separate entities from the cycle and mounted on a 1940s or 1950s bicycle made most installations different from one another.  From quite early days purchasers became unhappy with some aspect or other of a particular model and modified the original to what they thought was a better system.  Magazines such as "Power and Pedal" carried frequent articles on such topics as: "How I converted my Mini-Motor to chain drive" or "The £10 moped" (How to mount a Cyclemaster engine externally to the wheel).

It is against this background that I would argue to try and keep the hobby a relatively cheap one in which to indulge.  I would further suggest that in very many cases more satisfaction falls to the restorer by adapting parts himself than by purchasing replicas.  I do realise that this will not apply in all cases and that many restorers have no engineering knowledge or equipment.  It has certainly been my practice to use what I misquote as "Restorer's Licence" to make and adapt wherever possible.  I have now completed 28 models and have three more in the pipeline.  All are on cycles and most can be jumped on and ridden.  They frequently are - not many days pass when I do not go for a spin.

Some of the parts I have made are more true replicas than others.  Some are better functionally than the originals.  All enable me to get the bike on the road at very low cost, on the whole.  Examples are taken from back numbers of "Buzzing" and talking to other enthusiasts about what is usually missing.  I give some examples with a brief comment on how to replace the item:

  1. Cyclemaster exhaust - Electrical conduit bent by local electrician.
  2. Mini-Motor hoop frame - ditto; the mechanism for lifting on and off the wheel is converted to Mark I standard which, although not as positive, works and is easy to make.  Use the clutch lever off a scrap motorbike for a good pull at the handlebar - it is easy to make a click-in notch.
  3. Ducati Cucciolo pedal cranks can be made from standard pedal cranks but require some turning facility.
  4. Carburettors for various models.  These are very adaptable.  May I suggest a few extra alternatives?  Chain saws are available in a truly amazing variety of sizes.  The carbs are usually diaphragm type and so are not easily adapted in toto; jets, however, are.  Carburettors which are easy to find at autojumbles are the ones off Cyclemasters and Mini-Motors.  These cover 25cc, 32cc and 49cc engines.  Adapt to your motor with a jet from a chain saw stockist.  Carb modifications from other mopeds, all readily available from scrap-yards, are endless.  They are, however, almost certainly for 50cc engines, so if you use one on your under-50cc motor you will have to "jet down".
  5. BSA Winged Wheel petrol tanks - Visit your local scrap yard and look out for a Honda 50cc Graduate moped of the 1970's vintage.  You will have to saw the tank off the saddle pillar but thereafter, with a bit of mechanical (NOT welding) adaption it is very simple.  The tank is also very similar to that used on some versions of the Mosquito.  This moped is also a good source of ignition coils for the Vincent Firefly.  The carb is similar to a Power Pak's but the swan neck will need adaptation.
  6. Cyclemaster covers for the carb are much easier to make in either aluminium or copper, as it is easier to cut (use your wife's scissors when she is not looking).  Shape with a ball-ended hammer on a bag of sand.  When painted, who knows the difference?  Look on your tip for an old washing machine as the cover is usually aluminium.  For copper use a hot water cylinder or a piece from the scrap dealer.
  7. Cyclaid wheel drive pulley - washing machine?

The list is endless

Finally, I must emphasise that I am not offering a perfectionist's solution for a concours competition but rather a practical engineer's approach to the keeping-going of the fun of maintaining motorised bikes.

First published - May 1991

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