Description

Polaris 400/500 Master Tech Top End Rebuild Kit (1994–2014)

If your 1994–2014 Polaris 400 engine is losing compression, burning oil, or lacking torque, this Master Tech Top End Rebuild Kit restores performance and increases displacement to 500cc — with no case modifications required. This is a direct bolt-in 400 to 500 conversion designed specifically for Polaris ATV and UTV applications.

This rebuild kit is engineered for Powersports riders, professional mechanics, and DIY engine builders who demand durable, OEM-spec engines and parts. Whether you are repairing a worn-out top end or upgrading displacement, this kit delivers measurable gains in torque and throttle response.

Performance Benefits of the 400 to 500 Conversion

• Restores cylinder compression
• Increases displacement from 400cc to 500cc
• Improves throttle response and low-end torque
• Reduces oil consumption from worn valve seals
• Extends overall engine service life

All components are precision-manufactured to meet or exceed OEM tolerances. This ensures proper piston-to-cylinder clearance, valve seating, and timing system reliability — critical factors in long-term engine durability.

What’s Included in This Polaris Top End Rebuild Kit

• New Replacement Cylinder Assembly
• New Cast OE Style Replacement Piston
• 2 Forged Nitrite Intake Valves
• 2 Forged Nitrite Exhaust Valves
• Complete Top End Gasket Kit
• Timing Chain
• Timing Tensioner
• High Temp Valve Stem Seals
• Camshaft
• Exhaust Rocker Arm
• Intake Rocker Arm

Who Should Use This Kit?

• DIY riders rebuilding a Polaris 400 engine
• Shops performing top end service
• Owners wanting a 500cc upgrade without machining
• Mechanics replacing worn valves, camshaft, or cylinder

Warranty & Technical Support

This Polaris top-end rebuild kit includes a 1-year no-questions-asked warranty on all included parts. We build and supply high-quality Powersports engines and parts backed by decades of real-world testing.

Review our engine and parts warranty coverage for full details.

Need installation support or shipping information? Visit our help center.

For rebuild guidance and technical articles, explore the REV6 Powersports Blog.

Have fitment questions? Contact our team through our support page.

Frequently Asked Questions

Does this kit really convert a Polaris 400 to 500cc?
Yes. The included cylinder and piston increase displacement to 500cc without requiring crankcase modification. It is a direct bolt-in conversion.

Is this a complete top end rebuild solution?
Yes. The kit includes cylinder, piston, valves, camshaft, rocker arms, timing components, seals, and gaskets required for a proper top end rebuild.

Is this kit designed for DIY installation?
Yes. This kit is ideal for experienced DIY mechanics and professional repair shops familiar with Polaris engine service procedures.

Explore More Polaris Engines and Parts

Browse our full selection of Polaris engines and parts to find additional rebuild kits and engine upgrades.

Upgrade your Polaris 400 the right way. Order today and rebuild with confidence.