2004 - 2011 YAMAHA RAPTOR 350 YFM350 PORT & POLISHED BARE CYLINDER HEAD with KIBBLEWHITE VALVES & SPRING KIT

NEW STOCK CYLINDER HEAD KIT

REBUILD YOUR MACHINE WITH OUR NEW HIGH QUALITY OEM REPLACMENT CYLINDER HEAD KIT AND GET YOUR MACHINE UP AND RUNNING AGAIN!

The Smart Engine Builder's Secret: Maximizing Power Without the OEM Price Tag

When tackling a dirt bike or ATV engine rebuild, replacing a damaged cylinder head can quickly eat up the project budget. However, turning to a high-quality aftermarket cylinder head is one of the most cost-efficient moves you can make. It delivers the same reliable horsepower and torque as a factory original without the massive markup.

Here is exactly why aftermarket heads offer unbeatable value for your powersports machines:

• Zero "Brand Tax": You are paying purely for the aluminum and the machining, not the Yamaha, Honda, or Polaris logo stamped on the box. Dealership markup on factory parts drastically inflates the price.

• Lower R&D Costs: Aftermarket manufacturers reverse-engineer the original, proven OEM designs. Because they do not have to spend millions developing the engine architecture from scratch, they pass those massive savings directly to the builder.

• Advanced CNC Machining: Modern manufacturing technology has leveled the playing field. Independent factories now use the exact same high-precision 3D scanning, casting, and CNC porting equipment as the major brands, ensuring an identical fit and airflow rate.

• Direct Bolt-On Performance: These heads are cast to exact factory specifications. Valve seats, cam journals, and combustion chambers match the original geometry, meaning your compression ratio and fuel burn remain perfectly optimized for maximum power.

• High-Volume Specialization: Many aftermarket suppliers specialize entirely in casting and machining engine components. This laser focus and high-volume production drastically lower the cost per unit compared to an OEM that has to manage thousands of different vehicle parts.

Whether you are tearing down a top end for the track or getting a quad back on the trail, an aftermarket cylinder head gives you the exact same throttle response and reliability. It keeps the rebuild under budget while ensuring the engine performs exactly like it did on the showroom floor.

Kibblewhite Precision Machining (KPMI) high-performance lightweight racing valve spring kits are engineered to withstand the punishing environments and high-RPM demands of race-modified power plants. Designed using a strict "unified system" approach, these premium components out-perform and outlast factory OEM valvetrains, making them an essential upgrade for high-stress applications running aggressive aftermarket camshafts.

Key Features & Engineering:

• Advanced Metallurgy: Springs are progressively wound from high-strength Chrome Silicon (CrSi) or ovate wire, heat-treated, and shot-peened to deliver incredible resistance to fatigue and valve float.

• Mass-Optimized Retainers: Equipped with lightweight, FEA-designed (Finite Element Analysis) titanium or hardened heat-treated (H.T.) steel retainers that minimize top-end valvetrain weight without sacrificing structural integrity.

• Application-Specific Harmonics: Every kit is precisely engineered for its specific engine platform, balancing critical parameters like cam profiles, harmonic frequencies, mass, wire stress, and exact seat/open pressures.

• Complete Drop-In Security: Each kit provides a matched set of high-strength base washers, springs, and premium retainers—offering total valvetrain control, added clearance, and exceptional longevity under maximum lift conditions.

The Verdict: Whether you are building a high-revving motocross engine, upgrading an aggressive trail quad, or pushing extreme boost pressures, KPMI racing springs deliver the precise valvetrain control needed to protect your engine from catastrophic damage at peak RPM.

 

 WORKS BEST with STAGE 1 or 2 CAMSHAFT

KIT INCLUDES:

AFTERMARKET PORT & POLISHED CYLINDER HEAD

AFTERMARKET HEAD GASKET KIT (O-Rings, Retainers & bolts)

NGK D8EA SPARK PLUG

KIBBLEWHITE SPRING KIT 80-8000Racing Spring Kit (Titanium, 0.475" Lift)

KIBBLEWHITE BLACK DIAMOND EXHAUST VALVE (34mm head diameter)

KIBBLE WHITE BLACK DIAMOND INTAKE VALVE (40mm head diameter)