Piston ring kit OS 0.25 for the TRX 500 Foreman engine family restores seal and compression between the piston and cylinder, bringing the engine back to crisp, reliable performance. It fits Foreman FA/FE/FM/FPE/FPM models from 2005 through 2019, renewing power across trails and fieldwork with a precise chrome-plated steel ring set designed to withstand harsh use. By renewing the top, second compression, and oil rings, this kit helps reduce blow-by, lowers oil consumption, and restores consistent combustion without OEM pricing.

This aftermarket replacement is engineered to address common wear scenarios: worn rings allow compression loss, oil burns, and power fades, especially after long service in dusty, muddy, or heavy-duty conditions. The OS 0.25 kit provides a direct-fit solution that mirrors OEM specifications for a dependable seal, predictable starts, and steady performance under load—ideal for riders who rely on their Foreman for daily work or weekend excursions without chasing OEM parts.

Comprehensive Vehicle Fitment

Manufacturer	Models / Series	Years / Details
Honda	TRX 500 FA (Foreman)	2005-2019
Honda	TRX 500 FE (Foreman 4x4)	2005-2019
Honda	TRX 500 FM (Foreman 4x4)	2005-2019
Honda	TRX 500 FPE	2005-2013
Honda	TRX 500 FPM	2005-2013

Product Specifications

Attribute	Details
OEM Reference Part Numbers	13011-HP0-A01
Type	Piston Ring Set (OS 0.25)
Manufacturer	Aftermarket Replacement
Application	Honda TRX 500 Foreman FA/FE/FM/FPE/FPM (2005-2019); FPE/FPM (2005-2013)
Material	Chrome-plated steel alloy for wear resistance and sealing
Bore Size	STD 92 mm (verify exact bore before install)
Oversize	OS 0.25
Ring Configuration	Top compression ring, second compression ring, oil control ring

OEM & Aftermarket Cross-Reference Information

Part Number	Brand / Type	Cross-Reference Notes
13011-HP0-A01		Direct OEM reference for the TRX 500 Foreman; OS 0.25 equivalent aftermarket option
13011-P8F-A01		Std size ring set; cross-reference used for generation fitment notes
13011-RJA-004		Replacement lineage within the TRX 500 engine family; interchangeability guidance

What's Included

This kit contains the essential rings required for one TRX 500 piston assembly:

• Top Compression Ring
• Second Compression Ring
• Oil Ring

Note: Pistons, wrist pins, keeping/retaining clips, and gaskets are not included.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Precisely engineered to align with the TRX 500 Foreman engine design and OEM references for straightforward installation.
• OEM Cross-Reference: Aligns with Honda’s 13011-HP0-A01 lineage while offering a cost-effective OS 0.25 alternative.
• Premium Materials: Chrome-plated steel alloy provides improved wear resistance and sealing performance under harsh conditions.
• Precision Machining: Machined to OEM tolerances to minimize blow-by and maintain consistent combustion.
• Reliability in Rough Conditions: Built to withstand trail mud, dust, and farm duty without premature ring wear.
• Cost-Effective Performance: Restores power and efficiency at a fraction of OEM pricing, with dependable long‑term service life.

Installation Notes:

• Verify bore size before install: STD 92 mm is the standard; measure your cylinder bore to confirm compatibility.
• Check ring end gaps: Compare gaps to OEM specs for OS 0.25 rings to prevent seizure or mis-seating.
• Clean surfaces thoroughly: Remove oil, carbon, and debris from the piston grooves and cylinder lands prior to assembly.
• Lubricate rings during assembly: Lightly oil the rings and piston skirt to prevent hanging on initial startup.
• Install in correct orientation: Ensure each ring is oriented with its marked side outward or as specified by the OEM guide.
• Sealant and gaskets: Use fresh base and head gaskets where applicable; rings alone do not seal the entire top end without proper gaskets.

Why Upgrade?

Running a worn piston ring set leads to compression loss, higher oil consumption, and unpredictable performance. Replacing with this OS 0.25 kit restores the piston-cylinder seal, reduces blow-by, and returns consistent power and reliable starts for tough riding conditions.