Wiseco PK1112 ATV Top-End Piston Kit 100mm 11:1 Compression with Gasket Kit

The Wiseco PK1112 is a complete top-end piston kit engineered for the Yamaha Grizzly and Rhino 660, featuring a 100.00mm bore diameter and an 11.0:1 compression ratio. This all-in-one kit includes everything needed to perform a proper top-end rebuild — forged piston (Wiseco part number 4737M), piston rings, wrist pin, clips, and a full top-end gasket set.

Forged for Performance:

• 100% forged construction — Wiseco is the only U.S. aftermarket piston brand that exclusively uses the forging process, starting with aerospace-grade aluminum
• Condensed, aligned grain structure delivers superior resistance to impact and fatigue compared to brittle cast alternatives
• Skirt coating applied to reduce friction and promote longer service life
• Optimized strength-to-weight ratio — each forging is precision-designed using 3D modeling and finite element analysis software
• Dedicated forging tooling produced in-house for complete process control, from raw bar to finished part
• In-house dyno testing validates design integrity before the product reaches market

Kit Includes:

• Forged piston (100.00mm / 4737M)
• High-performance piston ring set
• Alloy wrist pin
• Retaining clips
• Complete top-end gasket kit

Wiseco PK-series piston kits are a trusted choice among ATV and UTV builders who demand proven performance. The forging process compresses and aligns the aluminum's molecular grain flow, producing a piston with greater ultimate strength, ductility, and fatigue resistance — qualities that are essential under the stress of high-performance and high-compression applications. Manufacturer Part Number: PK1112. Piston Part Number: 4737M.