YAMAHA TZ G

Certificate n°Q5886M

The Yamaha 250 TZ has been facing domination from Kawasaki’s twin-cylinder and rotary valve engines in GP racing for two years. To regain competitiveness, Yamaha needed to boost its power output. By increasing the rev limit by 500 RPM and using "open" port timing, the TZ250G (now with a 54.25x54mm bore and stroke) delivers more power at high RPM—but at a cost. This makes it a voracious consumer of pistons, which last no more than 150 km in race conditions, driving up maintenance costs significantly. The carburetors are now equipped with "Powerjets," similar to those on the TZ350F.