Wiseco PK1730 47.5mm Top End Piston Kit 10.5:1 Honda XR70 CRF70 +0.50mm Oversize

The Wiseco PK1730 is a complete top end piston kit designed for the Honda XR70R and CRF70F, featuring a 47.50mm bore (+0.50mm oversize) and 10.5:1 compression ratio. This kit delivers everything needed to perform a proper top end rebuild in a single package, using Wiseco's race-proven forged piston technology.

Kit Includes:

• Forged aluminum piston (4880M, 47.50mm)
• Piston rings
• Wrist pin and circlips
• Top end gasket set

Forged Piston Advantages:

• Superior strength-to-weight ratio — dedicated forgings reduce mass while maximizing structural integrity
• Improved tensile strength — forged material withstands higher mechanical stress than cast alternatives
• Condensed grain structure aligned to part geometry for enhanced resistance to impact and fatigue
• Aerospace alloy construction — same low-expansion alloy used by major OEM engine manufacturers
• Computer-engineered skirt profiles — optimized for precise cylinder fit, instant throttle response, and maximum torque

Specifications:

• Piston Diameter: 47.50mm (+0.50mm oversize)
• Compression Ratio: 10.5:1
• Piston Part Number: 4880M04750
• Kit Type: Top End (PK Series — includes gasket kit)

Wiseco is the only U.S. aftermarket piston manufacturer that produces pistons exclusively through the forging process, with all forging tooling produced in-house. This allows complete control over every stage of manufacturing — from raw bar stock to skirt-coated finished piston — backed by in-house dyno development and field testing.