This Piston Kit OS 0.75 is an aftermarket replacement designed for the TRX500 Foreman FA/FM/FE variants from 2012 to 2019 and the Pioneer 500/1000 from 2015 to 2023. It’s engineered to restore reliable compression and consistent power, delivering the same tolerances as OEM components while keeping proper bore clearance for dependable engine response under demanding ATV workloads. If you’re restoring trail or farm performance, this OS oversize kit helps bring worn cylinders back to life without the OEM price tag.

Designed to address common wear-and-tear issues on lifted or heavily used engines, this OS 0.75 piston kit targets compression loss, reduced throttle response, and uneven power delivery that plague aging TRX500 Foremans and Pioneers. The aftermarket replacement offers a reliable, cost-effective path to restore peak performance for both trail riding and field work, with a focus on durability and consistent operation in tough conditions.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

What's Included

What you get in the box when you order this OS 0.75 piston kit is the core components needed to rebuild the piston side of the engine:

• Piston
• Rings
• Wrist Pin
• Retaining Clips

Note: Gaskets, seals, and any additional hardware are not included unless explicitly specified.

Why Choose This Aftermarket Replacement?

• Direct-Fit Compatibility: Precisely matched to the same bore and piston geometry as the OEM design to minimize fitment surprises in the 2012–2019 Foreman models and 2015–2023 Pioneer UTVs.
• OEM Cross-Reference: Maintains alignment with Honda OEM references, making sourcing straightforward if you mix OEM and aftermarket parts.
• OS 0.75 Oversize Benefits: Restores compression and power in engines with bore wear, helping recover throttle response and steady power delivery under load.
• Premium Aftermarket Build: Engineered to tight tolerances, delivering durable performance that stands up to trail, field, and work-site conditions.
• Reliability for Trail & Farm Duty: Designed to perform reliably in harsh, off-road environments where engine demand is constant and high.
• Cost-Effective Maintenance: A high-quality alternative to OEM pistons that helps you keep performance up without the premium price tag.

Installation Notes:

• Verify Bore Size: Confirm the cylinder bore is appropriate for OS 0.75 (0.75 mm oversize) before installation to avoid interference or ring binding.
• Cleanliness Is Key: Thoroughly clean the piston, rings, and bore; remove all debris and pre-lubricate moving surfaces prior to assembly.
• Rings Orientation & Gap: Install rings with correct orientation and observe ring-end gaps per manufacturer guidelines to prevent blow-by and scuffing.
• Wrist Pin & Circlips: Use the new wrist pin and circlips supplied (or specified by the kit) and ensure they are fully seated to prevent engine damage.
• Lubrication & Assembly Lube: Apply a light coat of assembly lube to the piston skirt and rings to reduce initial wear during start-up.
• Follow Break-In Procedures: After installation, perform a proper break-in as per the service manual to seat rings and establish stable compression.

Why Upgrade?

Running a worn piston kit leads to progressive compression loss, reduced power, and uneven combustion, which can cascade into higher wear on other engine components. Upgrading to this OS 0.75 piston kit restores compression and power, delivering reliable throttle response and engine reliability for more confident trail riding and farm work. This replacement helps ensure you get back to full-strength performance without risking further damage from a tired piston.