Speedway Workshop

Today in Motorcycle History

The Yamaha YZ250cc

In 1994, the British Speedway Promoters Association and giant Japanese manufacturers Yamaha laid plans to stage a series of events through 1995 using a 250cc engine. It followed tests by former World Under 21 Champion and Coventry rider Brian Andersen who had a conventional speedway chassis adapted to accommodate a YZ250cc two stroke petrol driven engine.

He put the machine through its paces in front of an audience of all promoters at Coventry and it was later agreed to carry out a rolling experiment the following year in a series of second half events.

The prototype machine was built and prepared by Brian Davies from DIRTWHEELS of Coventry who estimated that the machine would cost £500 a year to maintain and that the only changes needed to convert a conventional speedway machine would be to have a different diamond and different engine plates.

Davies had been actively involved in speedway before, having been mechanic yo riders such as Nigel Boocock, Roger Hill and Frank Smith in the Coventry pits. He commented: "This machine was very, very impressive. The modern 250 does produce really good power and it would certainly cut down on costs.

To keep a 250cc two stroke engine going will be considerably cheaper than the 500cc engines that riders use".

The engine that Brian used came from the factory but was dead standard - exactly as anyone could buy for a moto-X machine throughout the world.

The off-shelf price of the YZ250 was £1,750 complete with clutch and accessories, some £500 cheaper than any conventional speedway engine counterpart, and maintenance costs would be dramatically cut.

One major appeal was the fact that the 5-speed gearbox would be retained and thus making riders change gears during the course of the race. Andersen went from the gate in third gear, changed up to fourth in the first turn and then up to fifth for the remainder of the flat-out laps.

A very similar project was started in 1988 in Germany by super sponsor MIKE KRAUSER (from the suitcases and the 4 valve heads for BMW). Mike, in co-operation with the German importers, built a total of 5 machines with 250 cc engines, these being supplied by HONDA; KAWASAKI; SUZUKI; YAMAHA and KTM.

The project was initially very promising, but as so often, a 2 stroke engine is not a very good powerplant for a speedway-machine.

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