Honda XR100 Piston Kit - Wiseco - 9.4:1 Compression Ratio - '81-'03. A forged 4-stroke piston kit by Wiseco designed to replace the stock piston in Honda XR100 models from 1981–2003, providing a reliable, OEM-size 55.00 mm option with a 9.4:1 compression ratio.

This complete kit is intended for riders and tuners who want a durable, installation-ready piston set. The forged construction optimizes strength and service life under typical riding stresses. Each kit includes the piston, wrist pin, rings, and circlips, so you have everything needed for a clean rebuild. The 55.00 mm bore and 9.4:1 compression ratio match common rebuild specs for XR100 engines; the design follows proven Wiseco manufacturing standards for consistent fit and performance.

Features

• Forged aluminum piston for improved durability
• 55.00 mm bore size, 9.4:1 compression ratio
• Complete kit: piston, wrist pin, rings, circlips included
• Engineered for 4-stroke XR100 applications ('81–'03)

If you have questions about fitment, installation, or suitability for your build, call us directly — our tech staff can help confirm compatibility and options. We offer installation and customization services at both of our locations in the Austin, Texas area and the Los Angeles, California area. Call: 512-982-9393 (TX) or 562-981-6800 (CA).

If you are considering purchasing multiple items, contact us for possible shipping discounts. We install on premises at both locations.

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov