Speedway Workshop

Sim 50 Junior Speedway

Designed for easy riding, the British made SIM50 was seen as an ideal training machine for children and adults alike at a low cost of just £120 in 1978. Powered by the Anker Laura engine fitted to the Ariel 3, the machine was built and designed by the Woodhouse Cornish Company of Suffolk and endorsed by John Louis.


Engine: 50cc Two-Stroke
Fuel: 2 Stroke Petrol + 2 Stroke Oil (16:1)
Tank : Approx 3 Pints.
Brake: Hub, cable operated Rear Brake
Gear: Single Speed with Automatic Clutch
Spark Plug:Champion L81 or equivalent
Wheels: 2" x 12"
Tyres: 2" x 12"
Weight: 22.5kg

Easy Starting

1: Turn petrol tap on. If cold, lift choke
2: Twist throttle grip away from you and push bike.
3: At walking pace, turn throttle towards you.
4: As engine fires, let grip go away from you into neutral for engine to tick over.
5: Close choke by returning to horizontal position
6: To accelerate, twist throttle towards you
7: To Stop engine, twist throttle grip away to decompress.


Tyre pressure: 20-22lbs p.s.i.
Greasing: Approximately once a month, grease nipple in steering Head shaft and nipple at end of reduction drive shaft. Every three months grease fork nipples sparingly. Use general purpose grease.
Chain: Lubricate with Engine Oil
Chain Adjustment: For reduction drive, loosen the three engine bolts. Tilt engine to rear to slacken chain, forward to tighten.

With the popularity and demand for such training bikes as the SIM50, John Louis also made another machine as shown below (1).

This other machine is a Junior bike and is fitted with a 50cc Sachs engine and a 7 speed gear box.

These machines were used for junior speedway racing in Sweden. The only difference to a normal speedway bike is the rear brake, which is compulsory in Sweden.

There are articles on the SIM 50 at The Moped Archive.

1. Some images missing are from this archive.
2. Details have been added to the orginal text.

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