This OS 0.75 oversize piston kit is designed specifically for the Honda TRX 350 Rancher models produced from 2000 through 2006. It increases the engine’s displacement by 0.75 mm, delivering a tangible boost in torque and smoother power delivery across the entire RPM range. Engineered to meet or exceed OEM tolerances, this kit helps restore compression and reliable performance when paired with proper bore measurements and compatible components. Rely on this OS oversize piston kit to address common wear in high-mileage Rancher engines: worn piston skirts, ring seating loss, and compression decline that robs throttle response and lugging torque. The 0.75 mm oversize option, when used with correct bore measurement and matching components, provides a durable upgrade for trail riding and farm work where consistent power matters.

Comprehensive Vehicle Fitment

Manufacturer	Models / Series	Years / Details
Honda	TRX350 Rancher FE (Rancher ES 4x4)	2000–2006
Honda	TRX350 Rancher FM (Rancher 4x4)	2000–2006
Honda	TRX350 Rancher TE (Rancher 2x4 ES)	2000–2006
Honda	TRX350 Rancher TM (Rancher 2x4 S)	2000–2006

Product Specifications

Attribute	Details
OEM Reference Part Numbers	13104-HN5-670
Type	Piston Kit OS 0.75 (Oversize)
Manufacturer	Aftermarket Replacement
Application	Honda TRX 350 Rancher (2000–2006)
Bore Size	79.5 mm (OS 0.75 oversize; typical for 0.75 applications)
Piston Material	Aluminum Alloy (AC8A)
Piston Style	Big Bore
Piston Type	Concave
Included Components	Piston, Rings, Wrist Pin, Circlips
Notes	OS oversize requires proper bore measurement and clearance to ensure optimal performance

OEM & Aftermarket Cross-Reference Information

Part Number	Brand / Type	Cross-Reference Notes
13104-HN5-670	Honda OEM	Direct cross-reference for TRX350 Rancher 2000–2006
13105-HN5-670	Honda OEM	Cross-reference for 0.75 OS big bore kits
13101-HN5-670	Honda OEM	Cross-reference supported in multiple listing sources

What’s Included

Comes as a complete top-end kit designed for an easy install on the affected TRX350 engines.

• Piston – OS oversize 0.75
• Rings – piston ring set
• Wrist Pin
• Circlips

Note: Gaskets, seals, and related base or head components are not included and may need to be sourced separately depending on your engine condition.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Engineered to align with OEM tolerances for a straightforward installation on 2000–2006 TRX350 Rancher models.
• OEM Cross-Reference: Includes established cross-references to popular Honda part numbers for easy compatibility checks.
• Premium Materials: Aluminum alloy piston designed for durable heat resistance and reliable high-RPM performance.
• Precisely Ground Bore: Oversize 0.75 design paired with proper bore measurement ensures optimal ring seal and compression.
• Performance Restoration: Restores original power and throttle response lost to wear, especially in demanding trail or farm use.
• Long-Term Reliability: Built to endure repetitive high-load scenarios and extended service intervals with proper break-in and maintenance.

Installation Notes:

• Measure the cylinder bore precisely to confirm compatibility with an OS 0.75 oversized piston.
• Inspect and clean the cylinder for scoring or damage before installation; de-glaze if necessary.
• Install piston rings with correct orientation and staggered end gaps per service manual guidelines.
• Lubricate the piston and rings with clean engine oil before assembly to reduce initial wear on startup.
• Secure the wrist pin with both circlips; ensure circlip grooves are clean and the clips are fully seated.
• Check piston alignment (arrow/mark) relative to the intake/exhaust orientation to avoid timing or seating issues.

Why Upgrade?

Running a worn top end on a TRX 350 Rancher compromises compression, throttle response, and overall reliability. This aftermarket OS 0.75 piston kit restores compression and reclaims lost power, delivering dependable performance for trail adventures or agricultural work.