Cylinder Works Big Bore Cylinder Kit – Yamaha YZ250 (1999–2024)

Unleash maximum 2-stroke power with the Cylinder Works 21009-K01 Big Bore Cylinder Kit, designed to transform your YZ250 into a 295cc powerhouse. This complete top-end upgrade includes everything you need for a bolt-on performance boost—no machine work required.

Description

Built for riders who demand factory-level reliability with race-grade gains, this kit combines a nickel-silicon-carbide plated cylinder, Vertex piston, and complete top-end package. Expect increased torque, improved throttle response, and a broader powerband across every gear.

What’s Included

✅ Cylinder Works 72.00 mm Big Bore Cylinder
✅ Vertex Piston Kit (piston, rings, pin, clips)
✅ Cylinder Head
✅ Power Valve Kit
✅ Top-End Gasket Kit
✅ Wrist Pin Bearing

Fitment

📦 Yamaha YZ250 (1999–2024)

Direct bolt-on installation—no machining required. Designed for stock crankshaft and head height.

Warranty Info

🛡️ Backed by Cylinder Works USA for manufacturing quality and performance.
Contact support for warranty or installation questions.

Key Features

• Increases displacement from 249cc to 295cc for more power and torque

• Nickel-silicon-carbide plated cylinder for extreme wear resistance

• Includes matched Vertex forged piston for precise performance

• OEM-style fit and finish—looks identical to stock

• Made in the USA

Price & SKU

💲 Retail Price: $1,106.95
🔑 SKU: 0931-1163 / 21009-K01
⚖️ Weight: 8.71 lb
📦 Ships next business day from stocked warehouse