Jazýčkový ventil (Reed Valve) - Racing - Yamaha DT 80 MX Type 5J1 1981

It is more than likely that your motorcycle has a steel reed as standard.
Fitting a Hy-tech fibre flexible reed will actually improve horse power and throttle response by opening sooner and then the steel type allowing more mixture into the engine. Matching the stiffness of the reed to the model of motorcycle takes considerable development. Hy-tech have years of experience in racing reed valve design ensures you get a reed that is best for your bike