Cylinder Works 21002-K01 80 mm Big Bore Cylinder Kit – Yamaha YZ250F/WR250F 2001-2013

Boost your Yamaha YZ250F or WR250F with the Cylinder Works 21002-K01 Big Bore Cylinder Kit, a direct bolt-on upgrade increasing displacement to 270 cc. This kit includes an 80.00 mm cylinder, Vertex piston, and top-end gaskets, designed for 2001-2013 models. We price-match reputable online stores—contact us to ensure you get the best deal!

✅ What’s Included

• Cylinder Works Big Bore Cylinder (21002-K01)

• Vertex Piston Kit (piston, rings, pin, clips)

• Top-End Gasket Kit

• Installation-ready, direct bolt-on design

• No additional hardware included (uses existing hardware)

🔑 Key Features

• Direct bolt-on big bore cylinder with +3.00 mm overbore; no machine work required

• Nickel-silicon carbide-plated cylinder sleeve for enhanced durability and long life

• Includes matched Vertex pistons for longevity, performance, and reduced engine noise

• Virtually identical appearance to OEM cylinders

• Made in the U.S.A.

• Compatible with 80.00 mm bore and 270 cc displacement

• 12.5:1 compression ratio, 4-cycle engine

• Warning: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

📦 Fitment (Highlights)

• Yamaha:

  • 2001-2013 YZ250F

  • 2001-2013 WR250F

• Notes: Always verify fitment by year, make, model, and engine specifications before ordering. Replaces OEM part numbers: 5NL113110000, 5UL113110000, 5XC113110000, 5XC113110100, 5XC113111000.

💲 Price & SKU

• Retail Price: $774.95

• SKU: 0931-0121 / 21002-K01

• Note: We price-match reputable online stores—contact us for the best price!

• Weight: 3.37 lbs

• Dimensions: 6.77" (H) × 10.03" (L) × 8.77" (W)

• Availability: In stock. Ships next business day

🛡️ Warranty

• Contact Cylinder Works for warranty details (proof of purchase required)

🔧 Installation Tips

• Torque cylinder head bolts to Yamaha specs (~20-25 ft-lbs, consult manual).

• Re-jet carburetor (e.g., Keihin PWK 35mm) for increased displacement—start with richer mains (e.g., 160-165).

• Verify cam timing and check oiling system due to higher compression.