Rocket Garage TZ250 race replica

Restored Rocket: Yutaka Hoshi’s Yamaha TZ 250 Factory Racer

Yamaha produced the mighty TZ 250 from 1973 all the way through to 2004. When the model was first released its 2-cylinder, water-cooled two-stroke engine produced 51bhp and was capable of a top speed in excess of 150 mph (240km/h). The model was sold commercially to the public as a factory-built race bike and during its first year of production, a TZ250 piloted by German rider Dieter Braun secured a World Championship title. 

In 1981 Yamaha completely redesigned the TZ 250 platform. The all-new design used a revised engine that had been proven capable by Yamaha racer Kenny Roberts in their 500cc machines. The model boasted an increased power figure of 57bhp, significantly improved reliability, a lighter frame, larger forks, a longer swingarm and fully adjustable mono-shock suspension. This bike, which was spotted on display at the 2022 Mooneyes Yokohama Hot Rod and Custom Show, is a 1982 Yamaha TZ 250J. It is the work of Yutaka Hoshi, the man behind the Japanese workshop Rocket Motorcycles which is located in the Ibaraki Prefecture on Japan’s east coast.

The project was essentially a restoration. Yutaka-san found the bike in Shizuoka near the famous Fuji speedway where it had likely once raced. The tired old TZ had been sitting unloved for decades so, with the goal of riding it himself at classic Japanese race events, he spent 6 months restoring The TZ 250J to near-new, all-original condition.

“This motorcycle hadn’t worked in 37 years, so I took it all apart, cleaned it, and reassembled it,” says Yutaka-san. “The engine was in very good condition, but the cowling had small cracks and dirty repair marks, so I had a hard time with the groundwork.”

With the purchase of the bike came an extensive collection of spares. The high-revving two-stroke engine of the TZ 250 needs regular rebuilds so the previous owner had a good stock on hand to keep his race bike performing its best. Many of these were put to use during the restoration but some things were missing.  So to complete the project Yutaka-san embarked on a global search to source everything he needed.

The most unique aspect of this restored TZ 250J is the colour scheme which Yutaka-san designed himself. The speed block pattern and graphics layout were inspired directly by the motorcycles ridden by Yamaha race team legend, “King” Kenny Roberts.

In 1978 Yamaha invited their dirt track racing champion, Kenny Roberts, to compete in the European World Championship Grand Prix. Many thought Roberts stood no chance of securing any stage wins that year due to his lack of road racing experience and knowledge of the European tracks. However, by the end of the season, Roberts had bagged enough points and podium placements to return home with the World Championship title.

Kenny’s World Championship win marked the first time an American had won the title but even more impressive was that Robert’s unorthodox style of road racing, which was heavily influenced by his dirt track riding, revolutionized motorcycle road racing. King Kenny repeated his World Championship win for both the 1979 and 1980 seasons. For these reasons and many of his other contributions to motorcycle racing, Kenny Roberts was named a Grand Prix Legend by the International Motorcycling Federation.

The motorcycle that inspired Yutaka-san’s design was King Kenny’s Championship winning 1980 Yamaha OW48. The 2 bikes schemes are almost identical with the exception of the number 2 race number as opposed to Kenny’s 1. Yutaka-san has also opted to put his own nickname, Hossy, on the sides of the windscreen and went with a blue Yamaha scheme as opposed to the yellow of Roberts’ race bike. The final paintwork was laid by Wedge motorcycles while the race numbers and Hossy lettering are the work of Japanese pinstripe artist Shakin’ Speedgraphix.

Unfortunately, the pandemic has put a stop to several race events in Japan this year where Yutaka-san planned to break in his freshly completed Yamaha TZ 250. You can rest assured though that as soon as things return to normal this bike will be getting its fair share of time on the track…and hopefully winning a few trophies of its own.