When your Honda TRX 420 Rancher starts losing power or burning oil due to worn piston rings, this oversize 1.00 piston ring kit steps in as the essential upgrade for models from 2007 to 2013. Designed specifically for the 420cc engine in these ATVs, it delivers a precise seal to restore compression and eliminate inefficient ring seating that hampers performance on rugged trails or farm duties. Swapping in this kit means regaining that dependable throttle response and reducing oil consumption, letting you tackle demanding rides with confidence and without the frustration of mid-ride failures. This aftermarket replacement tackles those issues head-on by using components engineered to match the exact groove geometry of your TRX 420 Rancher, ensuring a tight fit that prevents leaks and restores peak efficiency for both trail adventures and agricultural work. It's a reliable choice because it's built with the precision and durability that hold up under real-world stresses, giving you a cost-effective way to breathe new life into your machine without compromising on quality or performance.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

Based on standard piston ring kits for the TRX420 engine, this kit includes:

• Top Ring – High-carbon steel, chrome-plated for enhanced durability and wear resistance

• Second Ring – Cast iron or ductile iron for reliable heat management and sealing

• Oil Ring Set – Multi-piece oil control ring assembly with expander spacer

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

Why Choose This Aftermarket Piston Ring Kit?

• Extensive Vehicle Coverage: Precision-engineered for Honda TRX420 Rancher models spanning 2007 through 2013, including FE, FM, FA, TE, TM, FPA, FPE, and FPM variants, with aftermarket fitment extending through 2019 for some applications .

• OEM Cross-Reference: Cross-references genuine Honda part number 13012-HP5-600 for confident replacement, as verified in service manuals and parts diagrams for the TRX420 platform .

• Proven Aftermarket Support: Leading aftermarket brands including WSM , Wiseco , and Wossner  manufacture compatible piston and ring kits for these models, validating extensive aftermarket support for the Honda 420cc platform.

• Premium Materials:

  • WSM rings feature the same design as originals for interchangeability and include a complete oil ring set with expander spacer 

  • Wiseco pistons and rings are engineered, forged, and machined in the USA, with improved tensile strength for optimised service life 

  • Wossner components are manufactured in Germany, featuring elliptical design for uniform bearing surface and reduced localized pressure 

• Oversize Option: The 1.00mm oversize rings allow you to reclaim engineered clearances in worn cylinders after reboring to 87.50mm, restoring compression and combustion efficiency.

• Complete Ring Set: Includes top ring, second ring, and complete oil ring assembly with expander spacer for proper oil control.

Service Manual Information

The Honda TRX420 service manuals (2007-2013) provide detailed procedures for cylinder and piston service, including:

• Cylinder inspection for wear, scratches, and damage

• Piston-to-cylinder clearance measurement

• Ring end gap verification

• Proper ring installation orientation

• Torque specifications and tightening sequences 

Installation Notes:

• Ensure the cylinder is properly machined to the correct oversize specification (87.50mm final bore) before installation .

• 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 as outlined in the 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 with a compatible 87.50mm oversize piston from Wiseco , Wossner , or other quality manufacturers.

• 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 Honda TRX420 Rancher 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.