Yamaha Trials 2017
The trip to the Japanese World round always gives you an up-close and personal look at what the Yamaha trials team is developing. The trials project is led by Kimura San, who, Trial Magazine editor, John Hulme has known for many years starting with the mono-shock Yamahas in the eighties.
The latest prototype machine is code-named the 250F and was ridden by the 38-year-old Kenichi Kuroyama. This new for 2017 machine features the reverse cylinder Yamaha YZ engine housed in a modified frame from the old four-stroke model, married to a 2017 two-stroke Scorpa rear end. Suspension at the front is from the Tech brand whilst at the rear an Ohlin’s shock absorber with a remote cooling reservoir is used.
Many hand-fabricated parts are used and this machine is obviously a development model, and in truth looks very hand-built. The rear-facing exhaust port has created the biggest headache as Kimura has had to introduce a big front pipe to try and calm the huge amount of power from the fuel injected engine. Other novel weight-saving engineering exercises have been carried out such as drilling the front wheel rim between the spoke holes, very much like on the cycle trials bikes, and the fabrication of an aluminium air filter box.
John Hulme: “It’s always good to see Kimura San, who I have known since the John Shirt Snr days at the back-end of the Majesty Yamaha trials project and the start of the Mono-shock project in 1983. He is a very polite, modest guy who gives nothing away about a Yamaha return to trials. When I questioned him about the engine capacity in the new trials machines and the weight it was a polite, “I cannot say”. He always speaks about the good times with ‘Shirty Snr’ and I am sure in his heart he would love to see a new production Yamaha trials machine; I know we would”.