Piston Ring Kit OS 0.50 Oversize for Yamaha YFB and YFM 250cc Four Stroke Bear Tracker Bruin 1989 to 2009
Piston Ring Kit OS 0.50 Oversize for Yamaha YFB and YFM 250cc Four Stroke Bear Tracker Bruin 1989 to 2009 is backordered and will ship as soon as it is back in stock.
Delivery and Shipping info
Delivery and Shipping info
- Standard delivery (2-4 working days) - £4.99 on eligible UK mainland orders under £50.
- Express delivery - £6.99 on eligible UK mainland orders placed before 2pm.
- Large equipment including international orders are subject to different delivery rates and timescales.
Returns
Returns
Start Your Return Online (Recommended)
- Log In: Sign into your account on our website.
- Select Order: Navigate to your order history and select the item you wish to return.
- Initiate Return: Follow the simple prompts to start your return.
Piston Ring Kit OS 0.50 Oversize for Yamaha YFB and YFM 250cc Four ...
This OS 0.50 oversize piston ring kit is a direct-fit restoration solution for a 250cc four-stroke engine family used in trail-ready utility quads. It restores compression and oil control by renewing worn rings, delivering smoother starts and more confident power for rough terrain. With an OS 0.50 oversize designed to compensate mildly worn bores, this kit provides a cost-effective upgrade without OEM branding.
Ideal for riders tackling dusty trails and farm workloads, this aftermarket replacement addresses common wear that leads to blow-by, increased oil consumption, and loss of punch. The OS 0.50 oversize re-establishes sealing in mildly worn bores, helping restore throttle response, reduce smoking, and sustain reliable starts in Bear Tracker and Bruin engines for miles of hard-use performance.
Comprehensive Vehicle Fitment
| Manufacturer | Models / Series | Years / Details |
|---|---|---|
| Yamaha | YFB250 Bear Tracker | 1992–2000 |
| Yamaha | YFB250F | 1992–2000 |
| Yamaha | YFB250U | 1992–2000 |
| Yamaha | YFM250 | 1989–1991 |
| Yamaha | YFM250B (Bruin) | 2005–2009 |
| Yamaha | YFM250X | 1999–2004 |
Product Specifications
| Attribute | Details |
|---|---|
| OEM Reference Part Numbers | 4BD-11610-20-00 (OS 0.50); 4BD-11610-00 (STD 71.0mm); 4BD-11610-40 (OS 1.00) |
| Type | Piston Ring Kit |
| Manufacturer | Aftermarket Replacement |
| Application | YFB/YFM 250cc four-stroke engines (1989–2009) |
| Ring Stack | Top Ring, Second Ring, Oil Ring (3-piece set) |
| Bore Size (STD) | 71.0 mm |
| Oversize | OS +0.50 mm (71.50 mm) |
| Top Ring Material | Chrome Steel |
| Second Ring Material | Cast Iron |
| Oil Ring Material | Stainless Steel |
| Exact Oversize | OS 0.50 mm |
OEM & Aftermarket Cross-Reference Information
| Part Number | Brand / Type | Cross-Reference Notes |
|---|---|---|
| 4BD-11610-20-00 | Yamaha OEM | OS 0.50 Piston Ring Set for YFB/YFM 250; matches +0.50 oversize bore applications |
| 4BD-11610-00 | Yamaha OEM | STD 71.0 mm Piston Ring Set; base specification for the 71.0 mm bore family |
| 4BD-11610-40 | Yamaha OEM | OS 1.00 mm; alternative oversize for more bore wear |
| 2815XC | Piston Rings for Yamaha YFB/YFM 250; Bore 71.50 mm; OS +0.50; common cross-reference for +0.50 overbores |
What's Included
This kit provides the essential components needed to restore piston sealing on the Yamaha 250 family.
- Piston Ring Set – Top Ring
- Piston Ring Set – Second Ring
- Piston Ring Set – Oil Ring
Note: Piston, wrist pin, and circlips are not included.
Why Choose This Aftermarket Replacement?
- Direct-Fit Compatibility: Precisely matched to the 4BD bore family with STD and oversize options to fit worn engines without modification.
- OEM Cross-Reference Clarity: Clear cross-references to Yamaha OEM numbers ensure you’re selecting a true substitution that aligns with dealer catalogs.
- Premium Materials: Top ring in chrome steel, second ring in cast iron, and oil ring in stainless steel deliver durable wear resistance and reliable oil control.
- Performance Restoration: The OS 0.50 oversize re-establishes sealing in mildly worn bores, helping reclaim compression and throttle response.
- Rugged Reliability for Tough Duty: Built to withstand dust, mud, and extended trail or farm use while maintaining seals over time.
- Cost-Effective Replacement: A value-driven option that preserves engine life without the premium OEM price tag.
Installation Notes:
- Prep the bore: Inspect and measure the cylinder bore to confirm STD 71.0 mm or 71.50 mm with OS 0.50; clean the bore thoroughly before installation.
- Ring orientation: Ensure proper orientation of the top and second rings and stagger ring end gaps in the ring stack to minimize blow-by.
- Ring compression: Use an appropriate ring compressor sized for a 71.5 mm bore to avoid ring damage during installation.
- Lubrication: Lightly oil all rings before installation and lubricate the piston crown and skirt as you assemble to reduce dry start wear.
- End-gap checks: After installation, verify end gaps per service manual guidelines and adjust if required.
- Break-in procedure: After startup, avoid excessive load for the first 15–20 minutes; vary engine RPM to seat the rings gradually.
Why Upgrade?
Running a worn piston ring in this 250cc four-stroke family invites continued compression loss, increased oil consumption, and smoky starts. This OS 0.50 oversize kit restores sealing efficiency and oil control, returning dependable power and smoother operation for trail or farm work.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
