521M05800 Wiseco Piston Kit .080 for Yamaha YZ125 1985 58.00 mm

Wiseco .080 Piston Kit for Yamaha YZ125

This Wiseco .080 overbore piston kit for Yamaha YZ125 brings your top end back to spec with a 58.00 mm bore size, carrying OEM-style cross-reference 521M05800 for straightforward matching.

Overview

This Wiseco .080 piston kit for Yamaha YZ125 is a complete top-end rebuild solution for a worn or scored cylinder that has been bored to 58.00 mm. The kit cross-references 521M05800 and delivers the piston, rings, pin, and clips needed to restore compression. It suits riders and mechanics rebuilding 1985 YZ125 engines who want a proven overbore piston rather than a stock replacement.

Built For Performance

• Wiseco forged piston construction for strength under high rpm
• .080 overbore size of 58.00 mm to clean up a damaged cylinder bore
• Cross-reference 521M05800 for accurate part matching
• Kit includes piston, rings, wrist pin, and circlips
• Designed for two-stroke top-end rebuilds on the 1985 YZ125
• Machined ring grooves for consistent ring seal and compression

Fits These Machines

• for Yamaha YZ125 1985

On-The-Job Use

• Top-end rebuild after cylinder wear or piston seizure
• Overbore refresh when the stock bore is out of tolerance
• Motocross and trail riding maintenance on the YZ125
• Shop or home garage engine repair

Specs At A Glance

Good To Know

Q: Does this kit fit a stock, unbored cylinder? A: No, this is a .080 overbore piston sized at 58.00 mm and requires the cylinder to be bored and honed to match before installation.

Q: What is included with this piston kit? A: It ships as a top-end kit with the piston, rings, wrist pin, and circlips so you have the core parts for the rebuild in one package.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.