The OS 1.00 Oversize Piston Ring Kit is a purpose-built set of piston rings designed for the Honda TRX350 Rancher family, specifically the FM/TM/FE/TE models manufactured from 2000 through 2006. This oversize kit targets a worn bore to restore compression, tighten oil control, and seal a tired cylinder for dependable power on backcountry trails or farm work. With a +1.00 mm oversize configuration and a bore of 78.75 mm, it’s a precise, direct-fit solution when a rebuild is needed after wear and tear.

This aftermarket replacement delivers a reliable, cost-effective alternative to OEM pricing while maintaining genuine performance expectations. It addresses common wear-from-use issues like ringland glazing, oil blow-by, and compression loss, delivering consistent sealing and long-lasting reliability for hard-use Rancher applications. Built as a robust, trail-ready option, it’s the practical choice for riders and farmers who demand predictable power and smooth operation without downtime.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

In the box you’ll find the complete piston ring set designed for a single piston, ready to install with proper preparation of the bore and piston surfaces.

• Top Ring (compression ring)
• Second Ring (secondary compression/collection ring)
• Oil Rings (two pieces)
• Spacer Ring

Note: This kit includes rings only; pistons, wrist pins, circlips, or gaskets are not included. Related components for a full rebuild are sold separately.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility — designed to match the TRX350’s +1.00 oversize specification for reliable installation and sealing.
• OEM Cross-Reference — aligns with 13014-HN5-672 and widely used aftermarket cross-references for easy sourcing.
• Premium Materials — built for wear resistance and consistent oil control in four-stroke Yamaha-era environments, with rings sized for OS 1.00.
• Performance Restoration — restores compression, reduces oil blow-by, and re-establishes cylinder sealing for dependable power delivery.
• Cost-Effective Alternative — delivers OEM-level performance without OEM price tags.
• Trusted Aftermarket Brand — part of a carefully curated catalog designed for reliable service in trail and farm conditions.

Installation Notes:

• Verify bore condition and confirm the cylinder is prepared for a +1.00 mm oversize before installation.
• Measure ring end gaps per service manual and ensure correct side orientation for the top and second compression rings.
• Properly lubricate all rings and piston surfaces with clean assembly lube prior to installation.
• Use a proper piston ring compressor to avoid ring deformation during installation over the piston.
• Ensure the oil rings and spacer ring are oriented exactly as specified and seated in the groove correctly.
• After assembly, perform a cautious break-in procedure to seat the rings and verify no abnormal wear or leaks.

Why Upgrade?

Running a worn piston ring set leads to loss of compression and excessive oil consumption, which robs power and increases smoke and fouling. Upgrading to this OS 1.00 ring kit restores sealing, improves compression, and reclaims reliable, stable performance for demanding trail and field work.