598M04400 Wiseco Big Bore Piston Kit for Yamaha YSR50 1987-1992 44.00 mm

Wiseco Big Bore Piston Kit for Yamaha YSR50

This Wiseco big bore piston kit for Yamaha YSR50 machines lifts displacement on 1987 through 1992 models, cross-referencing 598M04400 at a 44.00 mm bore size.

Overview

This Wiseco big bore piston kit for Yamaha YSR50 mini sport bikes adds displacement to the small two-stroke motor used from 1987 through 1992. The kit runs a 44.00 mm bore and cross-references 598M04400, making it a straightforward way to rebuild or wake up a tired top end. It suits YSR50 owners, pocket bike builders, and hobby racers chasing more punch from the little single.

Built For Performance

• Wiseco forged piston construction for reliable service in a high-revving two-stroke
• Big bore 44.00 mm sizing increases displacement over the stock cylinder
• Cross-references part number 598M04400 for easy verification
• Kit format supplies the piston and matching components for the rebuild
• Suits fresh top end builds and performance refreshes on the YSR50

Fits These Machines

• for Yamaha YSR50 1987
• for Yamaha YSR50 1988
• for Yamaha YSR50 1989
• for Yamaha YSR50 1990
• for Yamaha YSR50 1991
• for Yamaha YSR50 1992

On-The-Job Use

• Top end rebuilds on YSR50 mini sport bikes
• Big bore builds that need a matching oversize piston
• Pocket bike and mini moto performance projects
• Refreshing a high-hour 50cc two-stroke engine

Specs At A Glance

Good To Know

Q: Does a big bore kit need cylinder work? A: A 44.00 mm big bore piston typically requires the cylinder to be bored, plated, or replaced to match the new size. Confirm your cylinder setup before ordering.

Q: Will this fit other Yamaha 50cc models? A: This kit is listed for the YSR50 from 1987 through 1992. Compare your bore and piston dimensions against the part number before purchase.

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