The ProX Exhaust Valve and Spring Conversion Kit, manufacturer part number 28.SES2414-1 and vendor part number 19-9549, provides a durable steel-valve replacement for select Yamaha four-stroke engines originally equipped with titanium exhaust valves. This complete kit includes steel exhaust valves and specially designed heavy-duty valve springs, offering a practical alternative for engine rebuilds and high-use applications.
ProX nitrided steel valves feature increased surface hardness and a smooth finish designed to reduce friction between the valve stem and guide. The included springs are manufactured from premium chrome vanadium steel to support the additional weight of steel valves while maintaining reliable performance at high engine speeds. The kit can be installed with the original equipment retainers, spring bases, and valve seals, eliminating the need for additional engine modifications.
Designed for fitment on 2014–2017 Yamaha YZ250F models, 2015–2017 Yamaha YZ250FX models, and 2015–2017 Yamaha WR250F models, this ProX conversion set is intended for replacing worn or damaged exhaust valves and springs during a cylinder head rebuild. Verify the motorcycle model year and engine configuration before installation to ensure proper application.
As a complete replacement package, the ProX 28.SES2414-1 kit supports a straightforward and efficient exhaust valve service using compatible OEM cylinder head components. It is suitable for riders, technicians, and engine builders seeking increased valve durability without changing the original cylinder head design.
Features:
- Application: Exhaust valve and spring conversion kit for select Yamaha four-stroke motorcycles
- Brand: ProX
- Manufacturer: ProX
- Manufacturer part number: 28.SES2414-1
- Vendor part number: 19-9549
- Valve construction: Nitrided steel valves provide increased durability, high surface hardness, and reduced stem-to-guide friction
- Spring construction: Premium chrome vanadium steel valve springs support reliable performance at high RPM
- Installation: Uses OEM retainers, spring bases, and valve seals without additional engine modifications
- Fitment: 2014–2017 Yamaha YZ250F, 2015–2017 Yamaha YZ250FX, and 2015–2017 Yamaha WR250F
- Kit contents: Complete exhaust valve and stronger valve spring replacement package
Fitment:
2014 Yamaha YZ250F
2015 Yamaha WR250F
2015 Yamaha YZ250F
2015 Yamaha YZ250FX
2016 Yamaha WR250F
2016 Yamaha YZ250F
2016 Yamaha YZ250FX
2017 Yamaha WR250F
2017 Yamaha YZ250F
2017 Yamaha YZ250FX
2018 Yamaha WR250F
2018 Yamaha YZ250F
2018 Yamaha YZ250FX
2019 Yamaha WR250F