790M08400 Wiseco Piston for Yamaha Wave Runner XL700 84mm .120

Wiseco .120 Overbore Piston for Yamaha Wave Runner XL700

This Wiseco .120 overbore piston, part numbers 790M08400, is an 84 mm (+3 mm) replacement piston for the Yamaha Wave Runner XL700, intended for cylinders bored to match the larger diameter.

Overview

This .120 overbore Wiseco piston for Yamaha Wave Runner XL700 personal watercraft is an 84 mm replacement built for engines that have been bored oversize. It restores compression and sealing on a rebuilt top end of a 1999 to 2004 XL700. The larger diameter suits cylinders machined to accept the +3 mm piston.

Built For Performance

• 84 mm diameter for a +3 mm overbore
• Forged aluminum construction for strength under marine load
• Precision-machined skirt and ring grooves for a dependable seal
• Wiseco part number 790M08400 for straightforward cross-reference
• Designed for rebuilt two-stroke top ends

Fits These Machines

• for Yamaha Wave Runner XL700, 1999-2004

On-The-Job Use

• Top-end rebuilds on a cylinder bored to 84 mm
• Refreshing a high-hours 701cc Yamaha marine engine
• Replacing a worn or damaged oversize piston
• Performance-oriented rebuilds of the Wave Runner XL700

Specs At A Glance

Good To Know

Q: Will this piston drop into a stock cylinder? A: No, this is an 84 mm overbore piston, so the cylinder must be machined to match that diameter before installation. Confirm your intended bore size and piston clearance with a machinist.

Q: Is this piston for both cylinders or just one? A: This listing is for a single piston. Check how many cylinders you are rebuilding and order the matching quantity for your top end.

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