6S5-12121-00-00 Exhaust Valve for Yamaha GP-R 1800 2019

Exhaust Valve for Yamaha

This exhaust valve, reference 6S5-12121-00-00, manages exhaust flow on the Yamaha GP-R 1800 to keep engine output steady through the powerband.

Overview

The exhaust valve is a replacement engine component for the Yamaha GP-R 1800, carrying the OEM cross-reference 6S5-12121-00-00. It governs when exhaust gases leave the combustion chamber so the engine holds consistent performance under load. Suited to riders and mechanics servicing a 2019 Yamaha GP-R 1800 watercraft.

Built For Performance

• Heat-resistant alloy construction rated for continuous exhaust exposure
• Precision-ground stem and seat for a dependable seal
• Cross-referenced to OEM part number 6S5-12121-00-00 for direct fit
• Holds exhaust timing stable at sustained high RPM
• Resists carbon deposit buildup and thermal distortion

Fits These Machines

• for Yamaha GP-R 1800, 2019

On-The-Job Use

• Top-end service on the Yamaha GP-R 1800 watercraft
• Engine rebuild after valve wear or poor compression
• Correcting exhaust flow when a valve sticks or burns
• Seasonal preventive maintenance replacement

Specs At A Glance

Good To Know

Q: Will this valve fit other Yamaha models besides the GP-R 1800? A: Fitment follows the part number 6S5-12121-00-00, so verify that reference matches your machine before purchase. A:

Q: Do I need special tools for installation? A: Standard valve spring compression tools used in Yamaha watercraft engine work are generally adequate. A:

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