If you're dealing with a Yamaha YFM or YFB 250 that's lost its punch due to worn piston rings, this OS 0.25 piston ring kit is the precise aftermarket solution engineered to restore engine compression and seal out issues like oil blow-by on models from 1989 to 2009. Designed specifically for the Yamaha 250 family, including popular variants like the Timberwolf and Bear Tracker, this kit tackles the common problem of ring gaps that lead to reduced power and efficiency during tough trail rides or farm work. By swapping in these high-precision rings, you'll experience smoother operation and renewed reliability, helping your machine perform as it did when it rolled off the line without breaking the bank on expensive OEM options. This aftermarket replacement stands out by delivering a perfect balance of durability and exact fit, addressing the wear-and-tear that plagues older engines by providing superior sealing and resistance to heat and pressure. It's a reliable choice for off-road enthusiasts and farmers alike, offering the performance restoration you need without the premium price, ensuring your Yamaha stays ready for whatever the trail or field throws at it.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

Based on standard piston ring kits for the Yamaha 250 engine, this kit includes:

• Top Ring – Chrome-plated steel for enhanced durability and wear resistance

• Second Ring – Cast iron for reliable heat management

• Oil Ring – Stainless steel for effective oil control and sealing

Note: This is a piston ring kit only. It does not include the piston, wrist pin, or circlips. For a complete top-end rebuild, pistons and additional components are available separately from various manufacturers .

Why Choose This Aftermarket Piston Ring Kit?

• Extensive Vehicle Coverage: Compatible with a wide range of Yamaha YFM250 and YFB250 models spanning 1989 through 2009, including Timberwolf, Bear Tracker, Moto-4, Bruin, and Big Bear variants .

• OEM Cross-Reference: Cross-references genuine Yamaha part numbers including 4BD-11610-00-00, 4BD-11631-00-Y0, 29U-11633-00-00, and 93450-17044-00 for confident replacement .

• Proven Aftermarket Support: Leading aftermarket brands including Namura , Wiseco , and Wossner manufacture compatible piston and ring kits for these models, validating extensive aftermarket support for the Yamaha 250 platform.

• Premium Materials:

  • Namura rings are manufactured to OE specifications from materials that maintain tensile strength and torque retention in operating conditions over 300°F .

  • Wiseco pistons and rings are forged from high-strength aluminum alloy in the USA, providing superior strength, reduced weight, and optimized designs that improve engine efficiency .

  • Wossner pistons are manufactured using state-of-the-art forging technology, offering high strength and durability with CNC precision .

• Oversize Option: The 0.25mm oversize rings allow you to reclaim engineered clearances in cylinders with minor wear, restoring compression and combustion efficiency without requiring a full rebore to larger sizes.

• Superior Sealing: The combination of chrome-plated steel top ring, cast iron second ring, and stainless steel oil ring provides excellent sealing, heat resistance, and oil control.

Installation Notes:

• Ensure the cylinder bore is within specification for the 0.25mm oversize rings. A light honing is typically recommended when installing new rings.

• Professional machining and assembly are recommended to ensure proper clearances and ring gap.

• Check ring end gap during installation to ensure it falls within factory specifications.

• Note that Wiseco rings are designed for use with Wiseco pistons; using them with other piston brands may result in improper fit .

• Follow manufacturer torque specifications and tightening sequences as outlined in the Yamaha service manual.

• This ring kit does not include the piston, wrist pin, or circlips – ensure your existing piston is in good condition or replace as necessary.

• After installation, properly break in the engine according to manufacturer recommendations.

• Verify your exact model and year against the fitment table to ensure compatibility with your engine configuration.

Why Upgrade?
Worn piston rings can cause compression loss, excessive oil consumption, and reduced power output—leading to poor performance and potential engine damage. Restore your Yamaha YFM250 or YFB250 engine's power and reliability with this quality aftermarket oversize piston ring kit, designed to keep you riding with confidence.

Order your piston ring kit today and get back on the trail with confidence.