Products Snowmobile- YamahaPiston Kit Back Piston Kit 09-816 Item number: 09-816 Bore Size: 73mm Stroke: 64 Fit on model: 1983-91 Yamaha VMX 540 You May Also Be Interested In Piston Kit 09-807-01 Piston Kit 09-808-02 Throttle Cable 0687-148 / 05-139-95 Piston Kit 09-807