797M05500 Wiseco .040 Piston Kit for Yamaha YZ125 2002-2004 55.00 mm

Piston Kit for Yamaha

This Wiseco .040 Piston Kit is a top-end rebuild component that restores compression and cylinder sealing in the Yamaha YZ125, cross-referencing 797M05500 at 55.00mm bore size.

Overview

This Wiseco .040 Piston Kit gives Yamaha YZ125 riders a complete top-end solution that restores lost compression and reliable cylinder sealing. Built for riders who want a durable overbore piston without hunting down individual components, this piston kit delivers matched rings, pin, and clips in one package. It is aimed at owners of 2002 to 2004 models who need a fresh top end for the track or trail.

Built For Performance

• Wiseco forged piston construction for strength under high-rpm loads
• .040 overbore size of 55.00mm for cylinders that need cleanup
• Complete kit with matched piston, rings, pin, and clips
• Cross-references 797M05500 for easy verification
• Designed for 2-stroke top-end rebuilds on the Yamaha YZ125

Fits These Machines

• for Yamaha YZ125 2002
• for Yamaha YZ125 2003
• for Yamaha YZ125 2004

On-The-Job Use

• Top-end rebuilds after a seized or scored piston
• Motocross and off-road engine refreshes
• Racers rebuilding between events
• Home mechanics restoring lost compression

Specs At A Glance

Good To Know

Q: Is this piston kit a genuine Yamaha part? A: No, this is an aftermarket Wiseco piston kit built to fit Yamaha YZ125 applications, so it is not an original Yamaha component.

Q: Will the .040 overbore require cylinder work? A: Yes, any overbore piston size generally requires the cylinder to be bored and honed to match, so have a machine shop confirm clearance before assembly.

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