Boyesen 620 Power Reed For: Kawasaki AR50 and AR80 all models; Yamaha DT50 all models, Yamaha MT80 all models, Yamaha MX80 all models, Yamaha RT100 1990-1995, Yamaha TY175 all models, Yamaha TY50 all models, Yamaha TY80 all models, Yamaha YZ50 all models, Yamaha YZ80 1974 Power reeds use a patented dual stage fiberglass design for more air flow, more air velocity and more power The top reed is lightweight and resilient for crisp throttle response at partial throttle or low RPMs; the stiffer, bottom reed is ported to provide maximum flow and horsepower at higher RPMs Longer overall life: Boyesen power reeds outlast all other aftermarket reed petals Minor change gives major horsepower improvements and fuel economy