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 09-8064 Piston Kit 09-800-01 Thermostat Kit 982554 Sleeve 23-29804 / 29804