Wossner 8630DC Piston Kit - 2006-2009 Yamaha YZ450F / 2013-2015 Gas Gas EC 450F Size C

Wossner 8630DC Standard Series Forged 4-Stroke Piston Kit - Size C

Maintain the legendary performance of your big-bore machine with the Wossner 8630DC Piston Kit. Precision-engineered for the 2006-2009 Yamaha YZ450F and the 2013-2015 Gas Gas EC 450F, this Size C forged kit is the professional choice for seasoned cylinders. At Moto-House MX, we know that after many hours of use, a standard piston can lead to power loss; Wossner’s Size C components restore the exact tolerances needed for high-hour cylinders to run like new again.

Forged from aerospace-grade aluminum alloy, the 8630DC maintains a reliable 12.3:1 compression ratio, providing smooth power delivery and excellent thermal stability. This kit incorporates Wossner’s signature radial boss machining and enhanced oiling slots for superior wrist pin lubrication—a critical feature for 450cc engines under the strain of adventure touring or motocross. The permanent skirt coating reduces internal friction and piston rock, ensuring a quieter engine and an optimized break-in. This Size C piston (94.98mm) is precision-matched for 95.02mm bores, making it the perfect solution for refreshing an engine where the cylinder has seen natural service wear.

Top Features: Wossner 8630DC Piston Kit

• Size C (94.98mm): Engineered for 95.02mm bores to restore factory-spec clearances in cylinders with moderate service hours.
• 12.3:1 Compression Ratio: Matches original performance specs for consistent power delivery and pump-gas reliability.
• Standard Series Forged Construction: Denser and more durable than stock cast pistons, providing superior resistance to fatigue at high temperatures.
• Advanced Lubrication Design: Radial boss machining and specialized oiling slots ensure the wrist pin stays lubricated during high-RPM operation.
• Low-Friction Skirt Coating: Permanent molybdenum disulphide coating protects cylinder walls and reduces internal drag.
• Complete Kit: Includes forged piston, high-performance rings, wrist pin, and pin locks.

Expert Pro-Tip: The Yamaha-based 450 engines are incredibly robust, but as the cylinder bore naturally expands over time, moving to a Size C piston is the best way to prevent "piston slap" and maintain peak compression. When installing the 8630DC, we recommend inspecting the cylinder for any deep scoring and ensuring it is within the 95.02mm range. Always use a fresh top-end gasket kit and premium synthetic oil to ensure your rebuild provides long-lasting reliability for your next off-road adventure.

Fitment List

Year Range	Vehicle Brand	Vehicle Model
2006-2009	Yamaha	YZ450F
2013-2015	Gas Gas	EC 450F

Frequently Asked Questions

Q: When should I choose a Size C piston?
A: Size C (94.98mm) is designed for cylinders that have worn slightly larger than the original factory specification. It is the proper choice to restore tight piston-to-wall clearances in used cylinders that are still within service limits but have surpassed the ideal fitment for Size A or B.

Q: Does this kit include the gasket set?
A: No, the kit includes the forged piston, rings, wrist pin, and locks. A complete top-end gasket set is sold separately and is required for a professional engine rebuild.

Q: Why choose Wossner for my Yamaha or Gas Gas?
A: Wossner is a leader in forged piston technology. Their pistons are much stronger than cast OEM parts, offering better durability and a higher safety margin for both competitive racing and long-distance adventure touring.

Recommended Pairings

• Complete Top End Gasket Set: Ensure a professional, leak-free seal and proper engine compression.
• Motorex Cross Power 4T Oil: Premium synthetic lubrication specifically designed for high-performance 4-stroke engines.

Restore your machine’s power and precision today. Buy now at Moto-House MX!

Moto-House MX – Choice of Champions – is located in Clermont/Montverde, FL. The Best Motocross/UTV & ATV Shop in Central Florida. Stop by our local store in Montverde, FL or enjoy lightning-fast shipping across the USA.