Vertex Big Bore OS Engine Rebuild Kit Polaris ATP / Scrambler / Sportsman 500 Vertex's OS Engine Rebuild Kits come fully packed with an oversized piston (+0.5-3.0mm larger than OE piston diameter) in addition to all the necessary parts and gaskets for a comprehensive engine rebuild or refresh. These kits can potentially save, on average, 400 in comparison to buying OEM components and between 7-15 when compared to purchasing aftermarket rebuild components separately. Helping to save money, down time and effort. Please note, these kits necessitate cylinder wall honing, machining and re-plating depending on the application and kit size. Includes: Vertex piston kit (larger diameter than OE piston size) Standard compression piston, rings, pin and clips Hot Rods heavy-duty crank Stock stroke On two-stroke applications, includes wrist pin bearing Hot Rods main bearing / seal kit Hot Rods transmission bearing kit Includes transmission bearings, output shaft collar and sprocket lock washer Hot Rods counter balancer bearing kit Hot Rods water pump bearing and seal kit Vertex complete gaskets kit Including seals and O-ring kit (covers top and bottom) Hot Cams cam chain Note : OS Engine Rebuild Kits require cylinder wall honing, machining and / or re-plating depending on application and kit size. Images for reference only. Kit contents vary with machine and application.