This STD bore piston ring kit is engineered to restore compression and sealing in the top-end of the 350cc engine family used across 2000–2006 Rancher FM, TM, FE, and TE variants. The kit aligns with OEM references 13010-HN5-671 and 13010-HN5-672, delivering a true drop-in upgrade without the higher OEM price. With the right bore size and ring design, it revives reliable power, cleaner combustion, and smoother cold starts for tough trail and farm duties.

Worn piston rings are a quiet killer for these engines, contributing to compression loss, oil blow-by, and smoky starts. This aftermarket STD bore kit is engineered to restore sealing and oil control to OEM-like performance, helping you maintain steady power and longer top-end life in demanding conditions. It’s a straightforward, cost-effective solution designed for easy installation on the affected top end.

Comprehensive Vehicle Fitment

Notes: These fitment ranges reflect the widely documented TRX350 top-end configurations for the listed model codes within the 2000–2006 window. References and cross-compatibility are commonly cited across aftermarket top-end components for these variants.

Product Specifications

Sources confirm the STD bore specification and OEM cross-reference alignment for these classic TRX350 top-end components. 78.50 mm is the standard bore size for the TRX350 top end in this era.

OEM & Aftermarket Cross-Reference Information

Cross-reference notes reflect OEM lineage and aftermarket compatibility for TRX350 top-end engines. The OEM numbers 13010-HN5-671 and 13010-HN5-672 appear across reputable aftermarket parts references as direct drop-in matches for STD bore rings.

What’s Included

This box contains the essential components for a single-cylinder STD bore top end ring set.

• Piston Ring Set (STD)

Note: Pistons, wrist pins, and circlips are not included. These items are typically packaged with full cylinder kits or piston kits, not with a standalone ring set.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Precisely sized STD bore set designed for 2000–2006 TRX350 Rancher variants (FM/TM/FE/TE) with minimal to no additional modification.
• OEM Cross-Reference Alignment: Maintains factory intent by matching 13010-HN5-671 and 13010-HN5-672 standards.
• Premium Materials & Engineering: Engineered to restore sealing and oil control to near-OEM performance for dependable top-end operation.
• Performance Restoration: Reinstates compression and clean burn, reducing power loss and oil blow-by under trail and farm conditions.
• Cost-Effective Alternative: Delivers OEM-spec fit at a substantially lower price point, helping you get back on the trail sooner.
• Reliability in Demanding Environments: Built to withstand the vibrations and heat of mixed-terrain use, keeping top-end reliability in tough conditions.

Installation Notes:

• Verify bore size is STD (78.50 mm) before installation; measure the cylinder bore to confirm compatibility.
• Thoroughly clean all ring grooves and oil passages in the cylinder to ensure smooth seating and oil control.
• Lubricate all rings with clean assembly oil or proper lube before installation to prevent scuffing on initial startup.
• Install rings in the correct order and orientation; ensure any manufacturer-facing marks are aligned per OEM patterns.
• Inspect and, if needed, replace related top-end gaskets and seals to prevent leaks after ring installation.
• Follow a gentle break-in procedure after installation to allow rings to seat properly and seal against the bore.

Why Upgrade?

Running a worn STD-bore top end ring set continues to degrade compression, increase oil consumption, and hasten wear in the cylinder. This replacement restores sealing and oil-control performance, renewing reliable power and long-term engine life for rugged trail and farm work.