Cylinder Works Standard Bore Cylinder Kit (422-20009K / 20009-K01) | Yamaha YZ250 (1999-2025)
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Complete high-performance standard bore cylinder kit engineered to deliver a comprehensive, ready-to-install top-end refresh for legendary two-stroke motocross engines. Features a premium cast aluminum cylinder finished with a durable nickel silicon carbide (NSC) electroplate bore and diamond honed to exact specifications, paired with matching top-end components to ensure optimal ring seal, reduced friction, and superior heat dissipation under aggressive racing conditions.
Specs & Details
- Manufacturer Part Number: 422-20009K
- Alternative Part Number: Cylinder Works 20009-K01
- Kit Type: Complete Standard Bore Cylinder and Piston Kit
- Bore Size: Standard (66.40 mm)
- Material & Construction: Cast aluminum cylinder with nickel silicon carbide plating, matched with high-strength forged or cast piston components
Two-Stroke Vehicle Fitment
| Make | Model | Engine Type | Year Range |
| Yamaha | YZ 250 | Two-Stroke Motocross | 1999–2025 |
TSO Garage Note
The ultimate hassle-free solution for bringing a YZ250 powerplant back to life. Instead of piecing together separate gaskets, rings, and pistons or waiting weeks for a replating service, this complete kit bundles a premium nickel silicon carbide-plated cylinder with matching top-end components. It delivers exact factory port timing, correct clearances, and rock-solid reliability for the track or trail right out of the box.
Compatibility
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