Yamaha released GYTR upgrade parts for the YZF-R9 in two stages:

Phase 1 – basic trackday upgrades
Phase 2 (WSS) – full race package used in World Supersport, including required FIM-approved parts

GYTR R9 Piston WSS (1PC)
Part No.: BKN11631GY00

Race-spec piston developed for the YZF-R9, built to handle high RPM use while improving combustion efficiency and overall engine output.

Compatibility:
YZF-R9 (2025+)

Type:
WSS piston (single unit)

Installation:
Professional fitting recommended. Best used with the full GYTR WSS engine setup for proper performance.