Upgrade the Kodiak 400 top end with an OS 0.25 piston kit designed to fit the FB and FW manual models from 1993 through 2012. This aftermarket replacement restores compression, power, and reliability after wear or overhauls, delivering a precise bore match and durable sealing for steady engine performance. The kit includes all essential components for a clean, accurate rebuild, enabling proper piston-to-bore fit and long-lasting engine responsiveness.

With an OS 0.25 bore, this kit targets common wear patterns such as ring-land wear and piston skirt scuffing that reduce throttle response and power. The high-quality aluminum alloy piston provides strength and heat resistance, while the included rings, wrist pin, and circlips ensure reliable sealing under load. Built for trail and farm use, this aftermarket replacement delivers dependable top-end performance when you need it most.

Comprehensive Vehicle Fitment

Compatibility overview sourced from aftermarket top-end listings confirms coverage across the Kodiak 400 and Big Bear 400 platforms (FB/FW variants included) spanning 1993–2012.

Notes: U.S. aftermarket catalogs consistently list these model ranges for Kodiak 400 and Big Bear 400 top-end kits, aligning with the 1993–2012 application window for this OS 0.25 piston kit.

Product Specifications

OEM & Aftermarket Cross-Reference Information

What’s Included

This OS 0.25 piston kit includes the following components:

• Piston
• Rings
• Wrist Pin
• Circlips

Note: Related gaskets, seals, and ancillary top-end components are not included unless listed above.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Engine-specific bore and oversize to match the Kodiak 400’s top-end, enabling a gasket-sealing, drop-in installation.
• OEM Cross-Reference: Provides a like-for-like solution when OEM parts are unavailable, with documented cross-list references.
• Premium Materials: High-quality aluminum alloy piston designed for strength, heat resistance, and longevity in demanding use.
• Performance Restoration: Restores original compression and throttle response, reducing power loss from wear and carbon buildup.
• Trail- and Farm-Ready Reliability: Built to withstand dirt, dust, and rough terrain common on trails and rural work.
• Clear Top-End Rebuild Path: Complete kit in one package minimizes downtime and simplifies the rebuild process.

Installation Notes:

• Verify bore size and oversize specification before installation; ensure the bore is clean and within measurement tolerances.
• Orient the piston correctly; align any orientation marks to the connecting rod (view the pin end and crown orientation during assembly).
• Lubricate the wrist pin and rings with clean assembly lube before installation to minimize initial wear.
• Install the rings with the correct side orientation and staggered gaps to promote proper sealing and reduce blow-by.
• Install circlips securely in their grooves; double-check clearance between the piston and cylinder walls to prevent binding.
• Follow break-in procedures in the service manual after rebuild to establish proper ring seating and seal formation.

Why Upgrade?

Running a worn piston kit undermines compression, throttle response, and overall reliability, especially under load. This OS 0.25 kit restores proper compression, seals the bore effectively, and returns the engine to predictable, sustained power for trail riding or farm work.