This Standard Bore Piston Kit, 68.5mm, is engineered to restore stock-level power and compression to your TRX 250 rebuilds from 1997–2001 (and compatible EX models through 2008). It includes a precision-machined piston, a complete ring set, a wrist pin, and circlips for a full top-end refresh. With a true 68.5mm bore, it preserves original clearance and sealing characteristics to bring back reliable performance on the trail or farm. Designed for straightforward installation, this kit aims to deliver consistent, dependable longevity ride after ride.

This aftermarket replacement delivers a value-forward rebuild that tackles common wear points: ring groove wear reduces compression, piston skirt scuffing harms sealing, and wrist pin or circlip wear can cause damaging end-play. By returning to the standard bore and stock-style components, the kit provides predictable combustion chamber behaviour, repeatable power delivery, and durable operation in demanding off-road conditions. It's a reliable choice for riders who want to restore performance without the expense of OEM-only parts on rugged terrain.

Comprehensive Vehicle Fitment

Product Specifications

OEM & Aftermarket Cross-Reference Information

OEM cross-reference numbers are provided for reference purposes only. Always verify fitment using your machine's exact model, year, and original part number before ordering.

What's Included

This kit provides all the components you need for a complete top‑end refresh in one box:

• Piston

• Piston Rings

• Piston Pin (Wrist Pin)

• Circlips

Note: Related gaskets, seals, or cylinder head components are not included.

Why Choose This Aftermarket Replacement?

• Direct-Fit Standard Bore Compatibility: Engineered to the exact 68.5mm standard bore specification, preserving original Honda clearances for a factory-correct rebuild.

• OEM Cross-Reference: Cross-references key Honda OEM part numbers (12100-HN6-000, 13101-HM8-A40, 13011-HM8-003) to ensure accurate fitment and performance without the OEM pricing.

• Complete Top-End Solution: Includes everything needed for the rotating assembly in the cylinder—piston, rings, pin, and circlips—eliminating the need to hunt for separate components.

• Restores Lost Performance: New piston and rings restore cylinder pressure, directly addressing power loss, low compression, and excessive oil consumption.

• Premium Construction: Built from quality materials and precision-machined for consistent compression, reduced wear, and reliable sealing.

• Cost-Effective Rebuild: Delivers OEM-level performance at an aftermarket value, ideal for trail riders and farmers seeking to extend the life of their machine.

Installation Notes:

• Verify Bore Size: Confirm the engine bore is exactly 68.5mm standard before ordering to ensure proper fitment.

• Inspect Cylinder: Check the cylinder wall for wear, scoring, or damage. A light deglaze or hone is typically recommended before installing a new piston kit.

• Lubricate During Assembly: Apply clean engine oil or assembly lube to the piston, rings, pin, and cylinder wall prior to installation.

• Orient Rings Correctly: Install rings with the correct orientation and stagger ring end gaps according to the service manual to prevent blow-by.

• Check Ring End Gap: Always verify ring end gaps fall within factory specifications.

• Install Circlips Securely: Ensure circlips are fully seated in their grooves and the gaps are oriented away from the cutout in the piston pin bore.

• Follow Service Manual: Adhere to all torque specifications and break-in procedures outlined in the Honda service manual.

Why Upgrade?

A worn piston and ring set is a primary cause of low compression, poor throttle response, and high oil consumption. Replacing them with this 68.5mm standard bore piston kit restores factory-like compression and reliable power, giving your TRX250 engine a fresh, responsive feel for years of dependable trail or farm use.

Order your piston kit today and get back on the trail with confidence.