Trojan Mini motor

In the late 1940's the Italians invented a small 50cc two stroke motor called the Mini Motore. This motor was primarily designed to power small lathes.A couple of years later, the motors were being produced in the U.K and the potential for use of the motor to assist bycicles was then realised and the motors were adapted to power bicycles. There were 5 versions made, Mark I, II, III & IV were 50cc models and the Mark was a 73cc model designed for tandem bicycles.

1952 MkII Trojan Mini motor.
Shown here is my 1952 MkII Trojan Mini motor that I have fitted to the front wheel of my bicycle.It runs well considering it age and it powers the bike along quietly at a maximum speed of 40km/hr. This setup is very simple as the motor drives the bike wheel via a drive roller in contact with the front wheel(the original trojans were mounted on the back wheel of the bike). I am using an old Victa metal fuel tank and a custom made exhaust. The custom exhaust was designed to improve performance of the motor and reduce the exhaust noise.

This trojan has the original cast iron drive roller which can seen in the above photo. This motor has an Amal Carby and a Bantamag magneto other versions of the Trojans had a Delorto carbys and a larger Wico Pacy magneto.While I have tried the Delorto and amal carbys on this motor, I have also tried using an old Victa Pace carby which performed well but was prone to flooding due to its larger capacity. There is a large Hex bolt on the head of the motor which can be seen in the photo, this plugs the decompression valve hole. This hole is the same size as the spark plug and so I have used a welded up spark plug base as a plug as I didn't have a decompression valve to put in the hole.

The whole setup(motor, tank etc) is mounted onto the bike via one bolt which also acts as the motor pivot. the motor pivot allows the motor to be lifted from the tire when the motor is not used. The bracket for the motor is fixed onto the frame of the bike via a bolt and a hose clamp. The hose clamp simply prevents the bracket from rotating. The mounting bracket can be identified as a  metallic red  bracket which is mounted against the front forks.This can be seen in the RHS of the photo.
 



Here is a view of the front forks showing the motor mounting bracket.

The round shaft that goes to the left of the photo is a long bolt onto which the motor bracket pivots on. The part of the bracket that is held on with a hose clamp, was cut out of an old pair of forks and fits nice and snug. I disconnected part of the brake cable for this photo so that the bracket was less obscured.








Here is a view from the front(with the motor mounted).



The tyre shown in this photo is not a smooth tyre. The knobs(large tread) works well as the friction roller tended to slip and wear the tire. In wet weather the friction drive didn't work much at all with the smooth tire.