Wossner 8958DB Piston Kit - 2019-2023 Kawasaki KX450 KX450X KX450SR Size B

Wossner 8958DB Premium Series Forged 4-Stroke Piston Kit - Size B

Refresh the heart of your Kawasaki 450 with the Wossner 8958DB Piston Kit. Engineered specifically for the 2019-2023 Kawasaki KX450, KX450X, and the high-performance KX450SR, this Premium Series forged kit is the professional choice for restoring "Factory Quality" power. At Moto-House MX, we know that as your engine accumulates hours, precise piston-to-wall clearance becomes critical; Wossner’s Size B components provide the exact tolerances needed to maintain peak performance in seasoned cylinders.

Forged from aerospace-grade aluminum alloy, the 8958DB maintains a high-performance 12.6:1 compression ratio, delivering the sharp throttle response and broad powerband that Kawasaki riders depend on. This kit features advanced radial boss machining and enhanced oiling slots for superior wrist pin lubrication—a critical upgrade for the intense thermal and mechanical loads of motocross and cross-country racing. The permanent skirt coating reduces internal friction and piston rock, resulting in a quieter engine and a more controlled break-in period. This Size B piston (95.97mm) is precision-matched for 96.01mm bores, making it the ideal choice for an engine refresh where the cylinder has experienced natural, minor wear.

Top Features: Wossner 8958DB Piston Kit

• Size B (95.97mm): Precision-engineered for 96.01mm bores to restore factory-spec clearances in cylinders with slight wear.
• 12.6:1 Compression Ratio: Delivers reliable, race-ready power that is compatible with high-quality pump fuel and racing blends.
• Premium Series Forging: Significantly stronger and more heat-resistant than OEM cast pistons, ideal for the high-impact stress of off-road racing.
• Advanced Lubrication Design: Radial boss machining and specialized oiling slots ensure the wrist pin stays lubricated during sustained high-load operation.
• Low-Friction Skirt Coating: Permanent coating reduces drag and protects your cylinder walls from premature wear.
• Complete Assembly: Kit includes the forged piston, high-performance rings, wrist pin, and pin locks.

Expert Pro-Tip: The 2019-2023 KX450 platform is a high-performance masterpiece, but maintaining proper piston clearance is vital to prevent "piston slap" and power loss. Size B is the preferred choice for a refresh when your cylinder is still in good condition but has worn slightly beyond the ideal clearance for a Size A piston. During installation, always verify your ring end gap and inspect your timing chain. Pairing this build with a fresh top-end gasket kit and premium synthetic oil will ensure your Kawasaki stays at the front of the pack.

Fitment List

Year Range	Vehicle Brand	Vehicle Model
2019-2023	Kawasaki	KX450
2021-2023	Kawasaki	KX450X (Cross Country)
2022-2023	Kawasaki	KX450SR (Special Racer)

Frequently Asked Questions

Q: When should I choose a Size B piston?
A: Size B (95.97mm) is designed for cylinders that have been broken in and have worn slightly larger than the original factory bore. This size restores the proper piston-to-wall clearance, helping to maintain optimal compression and engine longevity.

Q: Does this kit include the gasket set?
A: No, the kit includes the forged piston, rings, wrist pin, and locks. A complete top-end gasket set is sold separately and is required for a professional engine rebuild.

Q: Why choose Wossner for my Kawasaki KX450?
A: Wossner forged pistons are denser and stronger than original cast parts. They handle high heat and mechanical stress more effectively, providing a superior safety margin during aggressive racing and trail riding.

Recommended Pairings

• Complete Top End Gasket Set: Ensure a professional, leak-free seal and proper engine compression.
• Motorex Cross Power 4T Oil: Premium synthetic lubrication specifically designed for high-performance 4-stroke race engines.

Restore your machine’s power and precision today. Buy now at Moto-House MX!

Moto-House MX – Choice of Champions – is located in Clermont/Montverde, FL. The Best Motocross/UTV & ATV Shop in Central Florida. Stop by our local store in Montverde, FL or enjoy lightning-fast shipping across the USA.