When your Yamaha YFM 350 or 400 engine starts showing signs of age, like sluggish acceleration or oil leaks, upgrading to a precision-engineered piston ring kit in the OS 0.50 size can make all the difference for models from 1987 to 2014. This aftermarket piston ring kit is specifically designed for the 83.50mm bore family, ensuring a perfect seal in the combustion chamber to restore lost compression and enhance overall engine efficiency. By swapping out worn rings, you'll experience smoother operation and reliable power delivery, whether you're tackling rugged trails or handling daily farm chores, helping your quad run like new again. Its carefully machined design provides superior sealing and oil control, making it a smart, cost-effective choice compared to a full engine rebuild. You'll appreciate the reliability this aftermarket replacement offers, built to withstand the demands of off-road adventures or heavy-duty work without the premium price tag of original equipment.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

Based on standard piston ring kits for the YFM350/400 engine, this kit includes:

• Top ring – 1.2mm Nitride

• Second ring – 1.2mm ductile iron

• Oil ring set – 2.75mm chrome plating

*Note: This is a piston ring kit only. For a complete top-end rebuild, pistons are available separately from manufacturers like Wiseco (4676M08350)  and XYRVICT .*

Why Choose This Aftermarket Piston Ring Kit?

• Extensive Vehicle Coverage: Compatible with Yamaha YFM350 models (1987-2014) including Big Bear, Bruin, Grizzly, Moto-4, Raptor, Warrior, and Wolverine, plus YFM400 models (1993-2011) including Big Bear and Kodiak, with fitment confirmed by multiple aftermarket suppliers .

• OEM Cross-Reference: Cross-references genuine Yamaha part number 4GB-11610-20-00 for confident replacement, as verified in Yamaha OEM parts diagrams .

• Proven Aftermarket Support: Leading aftermarket brands including Wiseco  and XYRVICT  manufacture compatible piston and ring kits for these models, validating extensive aftermarket support for the Yamaha 350/400 platform.

• Premium Materials:

  • Wiseco pistons are forged from high-strength 2618 aluminum alloy in the USA, providing improved tensile strength, optimized strength-to-weight ratio, and superior service life .

  • XYRVICT rings feature nitride top rings, ductile iron second rings, and chrome-plated oil rings for enhanced durability and oil control .

• Oversize Option: The 0.50mm oversize rings allow you to reclaim engineered clearances in worn cylinders, restoring compression and combustion efficiency without replacing the entire cylinder.

• Enhanced Engine Efficiency: Proper ring sealing maintains optimal cylinder pressure, resulting in improved power and performance .

• Long-Lasting Performance: Engineered for durability, these rings are built to withstand the demands of everyday riding and heavy-duty work .

Installation Notes:

• Ensure the cylinder is properly machined to the correct oversize specification (83.50mm) before installation.

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

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

• Note that Wiseco piston kits include rings, wrist pin, and circlips – this ring kit is compatible with Wiseco pistons .

• 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 YFM350 or YFM400 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.