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 09-807-02 Piston Kit 09-831-03 Manifold Gasket 3852472 / 909613 Exhaust Gasket 09-718192 / 718192 / 720-931-615