Wiseco 4394M06550 65.50mm 10.25:1 Compression ATV Piston Kit .020 Oversize

The Wiseco 4394M06550 is a high-performance forged piston kit designed as a .020" (0.50mm) oversize replacement for Honda ATC and TRX 200cc four-stroke ATV engines. Featuring a 65.50mm bore diameter and 10.25:1 compression ratio, this piston kit delivers the strength and precision that performance ATV riders demand.

Wiseco pistons are forged from high-silicon, low-expansion aluminum alloy, offering superior strength, reduced weight, improved heat transfer, and extended service life compared to cast alternatives. Each piston is diamond-turned on CNC equipment to guarantee a precise finish and consistent sizing. As the only U.S. manufacturer producing pistons exclusively through the forging process, Wiseco maintains full in-house control from raw material to finished product.

Kit Contents:

• One (1) forged piston
• Piston ring set
• Wrist pin
• Piston pin circlips

Key Features:

• 65.50mm bore diameter — .020" oversize; requires cylinder boring or honing
• 10.25:1 compression ratio for strong power delivery
• Forged high-silicon aluminum construction for superior durability
• CNC diamond-turned finish for precise fit and minimal size variation
• Manufactured in the USA at Wiseco's Mentor, Ohio facility
• Only Wiseco replacement ring sets should be used on Wiseco pistons

This oversize piston is ideal for engine rebuilds where the cylinder bore has been worn and requires machining to the next oversize dimension. Pair with a matching top-end gasket set for a complete rebuild.