ProX Steel Intake Valve and Spring Kit 28.SIS2414-2 — Yamaha YZ250F YZ250FX WR250F 2014-2019

Product Description

Ditch the maintenance headaches of stock titanium valves with the ProX Steel Intake Valve and Spring Kit. This kit is specifically engineered to replace OEM components with highly durable nitrided steel valves, providing significantly increased wear resistance under the extreme heat and stress of off-road riding. By switching to steel, you get a valve that holds its seal longer and offers incredible reliability for long-term engine performance.

Because steel valves are heavier than titanium, this kit includes specially designed valve springs manufactured from premium chrome vanadium steel. These springs are engineered to handle the added mass while providing improved performance and durability at high RPMs. Designed as a complete package, this kit is fully compatible with your existing OEM retainers, bases, and valve seals, making it an excellent, cost-effective solution for your next cylinder head rebuild.

Top Features: ProX Steel Intake Valve and Spring Kit

• Nitrided steel construction significantly increases valve life and wear resistance.
• Includes upgraded chrome vanadium springs to compensate for steel valve mass.
• Optimized for high-RPM performance and long-term durability.
• Direct-fit design works perfectly with stock retainers, bases, and seals.
• The reliable choice for riders looking to maximize service intervals.

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Frequently Asked Questions

Q: Why would I choose steel valves over titanium?
A: Steel valves are much more durable and resistant to heat-related degradation than titanium valves. While they are slightly heavier, they are the preferred choice for riders who want to extend their service intervals and minimize the risk of valve failure.

Q: Do I need to re-cut my valve seats?
A: Yes, whenever you install new valves, we highly recommend having a machine shop cut the seats. This ensures the valve face mates perfectly with the seat, which is essential for proper heat transfer and engine performance.

Expert Pro-Tip: Since you are moving to a heavier steel valve and an upgraded spring, ensure your valve guides are in perfect condition. Any extra slop in the valve guide will be magnified by the heavier valve and cause the seat to wear prematurely. If the guide is worn, replace it to get the full life out of your new ProX kit.

Recommended Pairings:
o Yamaha YZ250F / YZ250FX Performance Parts
o High-Temp Assembly Lube
o Cylinder Head Rebuild Tools

At Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.

Moto-House MX – Choice of Champions – Clermont / Montverde, FL. Central Florida's premier powersports source with lightning-fast worldwide shipping.