Motorcycle Parts

Increase the power of your 2009 Honda CRF450R with the new Cosworth Pro-Max CNC Cylinder Heads. Over 40 years ago, Cosworth began its legacy as a leading designer of multi-valve cylinder heads for the highest level of motorsports.

Through its successful professional engine programs for motorsports such as Formula One, Cosworth has gained an intimate knowledge of cylinder head flow and fuel atomization characteristics in ultra-high RPM environments.

Today, Cosworth has extended this knowledge to the motocross stage and is proud to announce the release of Cosworth Pro-Max cylinder heads for the 2009 Honda CRF450R.

Through a combination of hands-on testing and extensive engineering, Cosworth's Pro-Max cylinder head team developed precise intake and exhaust ports with specific, enlarged dimensions to maximize gas velocity. Knife edged port dividers, ultra-fine port walls, and CNC multi-angle valve seats channel air and fuel without obstruction resulting in enhanced flow.

Combustion chamber volume is left unchanged to maintain consistent compression ratio.

Compatibility, reliability, and stringent quality control are paramount concerns at Cosworth. That's why every Pro-Max CRF450R cylinder head begins its life as a brand new OE casting. Each casting is 100-percent CNC ported, ensuring every cylinder head is identical.

All Pro-Max cylinder heads utilize standard seats and guides ensuring compatibility with your valvetrain of choice. Additionally, the cylinder head fire face is lapped to free the gasket-mounting surface of any defects or gaps, which could lead to lifting.

Each Cosworth Pro-Max Cylinder Head is delivered ready for assembly using your own preferred components and is also available with reduced guides for race applications.

Part Number: 20019396

Performance with standard size valves:
Intake: 13.2% Increase (CFM) @ .400" lift
Exhaust: 11.9% Increase (CFM) @ .400" Lift