Trojan Minimotor 49cc, 1952


The Trojan Minimotor was designed in 1946 by Vincenti Piatti and by 1948 was being manufactured, under licence, by the Trojan company of Croydon (the same company which made the well known Trojan vans used by Brooke Bond).

It must be remembered that in the years immediately following the war, Europe was desperate for transport. Nevertheless, it must have been quite a feat to have sold over 100,000 units by 1951.

The beauty of the Minimotor lies in its simplicity. The small two-stroke cylinder is hung beneath the petrol tank with one end of the crankshaft driving the magneto and the other endTrojan Minimotor prepared for initial adjustments having a drive roller to bear on the rear tyre. There is no clutch but instead a handlebar lever operating a cable mechanism to raise or lower the engine onto the tyre. A small carburettor regulates the petrol flow, by handlebar control. Apart from the lifting mechanism that's all there is to it. 

With easy, open access to the engine this really was a motor which could be decarbonised during your lunch break.

Mine is one of the early Mk I models; it lacks a decompressor and the handlebar lever pulls the engine down onto the tyre. This makes control of my early model, interesting.......... One is used to a 'clutch' lever engaging the drive when released, but on this early unit it works the other way round, squeezing the control engages drive, releasing it frees the drive,  and this takes a certain mental agility, at least on the maiden ride!

The engine has been carefully rebuilt by Rob Pointing, who has owned it since 1983. Rob fitted new bearings and seals and it purrs along quite nicely - he was particularly keen to point out how well it ticked over at standstill for a little two-stroke.

The unit was bought complete, mounted on an attractive dark green Gent's Raleigh. The bike is nicely mellowed with most of the original paintwork intact and traces of faded gold lining, obviously much polished over the years. I will be touching up the few scratches and repainting the mismatched oilbath chainguard but not taking a complete strip and paint. 

The front wheel is a Westwood in quite good condition but the rear rim is a poor condition Westrick. I have a nice pair of stainless Westrick rims and might fit these and replace the rod brakes with cable operated calipers. I already have the rod braked Triumph roadster and have to admit that periodic adjustment is easier with cable brakes. Later Raleighs of this type were in fact fitted with cable brakes and the similar Raleigh Superbe sported stainless rims.

Lighting is a problem. The machine has a dynohub but not a magneto driven lighting coil and I would imagine that lights which expire when the bike is stationary are not allowed on a motor driven machine. The alternative is to remove the lights and have it MOT'd for daylight running only. 

Recent Note: One way around this may be to fit a battery pack to the seat tube, as originally fitted to many of these types of bikes. The best model, with a filter unit, is initially switched to battery lighting and automatically changes to dynamo lighting once the dynohub is generating sufficient volts. so this should allow compliance with the law. Note also that I have read that the rear number plate does not have to be illuminated on machines of less than 50cc, so it should be permissible to run on a normal rear light, too - might need an informed MOT tester to accept this but I'm assured it is correct.

Thinking of buying one?
These are fairly robust little engines, easy to work on with most parts available. However, check that you are getting all of the parts, the support hoop and lifting mechanism are often missing and then there's the lifting and throttle levers, too. Missing parts isn't the end of the world but make sure that the price allows for it, all the little bits soon mount up ...................

Just a mere two years or so after buying the Minimotor I've been able to give it a reasonable run, on private property. It goes really well, a little too well for a bicycle and certainly too well for bicycle rim brakes! I believe that this was one of the more powerful cyclemotors and it certainly feels it even pulling my 15 stone frame.

The only problem is that the tank has a lot of loose rust sediment which tends to block  the petrol flow. One piece of advice I came across was to put some nuts and bolts in the tank and give it a good shake and once its all cleaned out, to fill it and store it with a strong oily petroil mix.