393M06400 Wiseco Std Piston Kit for Yamaha RD350 RD400 1973-1979 64.00mm

Wiseco Std Piston Kit for Yamaha RD350 & RD400

This Wiseco standard piston kit, reference 393M06400, is a 64.00 mm bore piston assembly for the Yamaha RD350 and RD400 two-stroke twins produced from 1973 through 1979.

Overview

This Wiseco Std Piston Kit for Yamaha RD350 and RD400 restores factory bore size on tired two-stroke top ends. Each Wiseco piston kit for Yamaha RD350 and RD400 is forged for strength and machined to 64.00 mm so the cylinders can be honed and refreshed without going oversize. Riders rebuilding a classic RD top end get a Wiseco piston kit for Yamaha RD350 and RD400 that handles high rpm running.

Built For Performance

• Forged aluminum construction for greater strength than cast pistons
• 64.00 mm standard bore size matches original cylinder dimensions
• Wiseco 393M06400 series piston for the RD350 and RD400 engine family
• Designed to withstand the stresses of a two-stroke powerband
• Suited to rebuilds where cylinders clean up at the factory bore

Fits These Machines

• for Yamaha RD350 1973-1979
• for Yamaha RD400 1975-1979

On-The-Job Use

• Top end rebuilds on RD350 and RD400 street bikes
• Restoring a classic Yamaha two-stroke to running condition
• Refreshing cylinders that measure within standard bore spec
• Vintage motorcycle engine repair work

Specs At A Glance

Good To Know

Q: What does standard bore mean on this piston kit? A: Standard bore means the piston matches the original 64.00 mm cylinder diameter before any overboring, so it fits cylinders that still measure within spec.

Q: Do I need to measure my cylinder before ordering? A: Yes, check cylinder wear and taper first, since a worn or scored bore may need an oversize piston instead of this standard size.

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