Top End

Complete kits include cylinder sleeves, pistons and head gasket750cc kit increase bore and stroke to 83.5mm x 67.8mm (stock is 78 mm x 67.8 mm)865cc Increases bore and stroke to 90 mm x 67.8 mm...

The lightest rocker arm available, but still has superior strength characteristics due to its designThe strength of 660 bronze bushings and bearing-grade steel for the roller tipExtensively tested...

Kits include aluminum cylinder with nickel-carbide coating designed with larger water jacketsForged piston with molybdenum coatingSpecial gasket kitEasy-to-follow step-by-step installation...

Ready-to-install, direct bolt-on cylinders require no re-plating and look virtually identical to the OEM cylindersCylinder kits include matched Vertex pistons to ensure longevity, performance and...

Ideal engine part to complete Koso's big bore kitUnique four-valve design increases air flow and performanceProvides more power and torqueFeatures a forged piston, stainless steel 24 mm intake valves...

Kits contain all items to completely refresh and upgrade cylinder heads for popular Dirt/MX and Side x Side modelsCylinder Head Service Kits include the below components:Lightweight Racing Valve...

Kits include aluminum cylinder with nickel-carbide coating designed with larger water jacketsForged piston with molybdenum coatingSpecial gasket kitEasy-to-follow step-by-step installation...

Kits include aluminum cylinder with nickel-carbide coating designed with larger water jacketsForged piston with molybdenum coatingSpecial gasket kitEasy-to-follow step-by-step installation...

Bolt-on cylinder setFor 4.375" stroke motorsMade in the U.S.A.

Bolt-on cylinder setFor 4.375" stroke motorsMade in the U.S.A.

Bolt on Cylinder Set For M8 Models

Stock replacement cylinders, 3.5" bore with cast-iron linerFor 80" or 89" enginesMade in the U.S.A.