Wiseco PK1889 4-Stroke Forged Piston Kit 96.00mm Bore 12.5:1 Compression ArmorGlide

The Wiseco PK1889 is a complete 4-stroke forged piston kit engineered for the Kawasaki KX450F, delivering a 96.00mm standard bore at 12.5:1 stock compression ratio. Designed for high-performance motocross use, this kit features Wiseco's proprietary ArmorGlide skirt coating, which reduces friction, minimizes piston rock noise, and allows the piston to be fitted tighter within the bore for an improved ring seal and maximized horsepower.

Wiseco is unique among aftermarket piston manufacturers in that all pistons are forged entirely in-house at their facility in Mentor, OH, with all forge tooling also produced on-site. This end-to-end control of the manufacturing process — from raw bar stock to finished skirt-coated parts — ensures consistent quality and the tightest possible tolerances.

Key Features:

• 96.00mm standard bore with 12.5:1 stock compression ratio
• ArmorGlide skirt coating for reduced friction, better ring seal, and increased horsepower
• Aerospace-alloy forged construction — superior strength-to-weight ratio versus cast pistons
• Dedicated application-specific forging optimized for the KX450F engine geometry
• Condensed, aligned grain structure for higher mechanical properties and resistance to impact and fatigue
• Engineered, forged, and machined in the USA
• Includes high-quality piston rings, wrist pin, and circlips
• Top-end gasket kit included

Unlike cast pistons, which are brittle and prone to catastrophic failure when yield strength is exceeded, Wiseco forgings feature a condensed grain structure aligned to part geometry — delivering the toughness and durability that extreme racing demands. In-house dyno testing drives continuous development of Wiseco's piston shapes, coatings, and components, keeping them at the forefront of 4-stroke motocross performance.