PHATHEAD YZ250-PHATHEAD-Y21 Racing Billet Cylinder Head

( Brand: Phathead ), ( Manufacturer Part Number: YZ250-PHATHEAD-Y21 ), ( Engine Type: 2-stroke ), ( Type: Cylinder Head ), ( Unit Type: Unit ), ( Machine Type: Off-road Motorcycle ), ( Manufacturer Warranty: 1 Year ), ( Material: Aluminum ), ( Vintage Part: No ), ( California Prop 65 Warning: True )

Review PHATHEAD Racing Billet Cylinder Head Yamaha Y21 Insert fits YZ250 1999–2026

Introducing the PHATHEAD YZ250-PHATHEAD-Y21 Racing Billet Cylinder Head, a high-performance upgrade for your Yamaha YZ250 motorcycle model years 1999 to 2026. This aftermarket cylinder head is meticulously engineered and manufactured using only the finest billet aluminum material to ensure superior strength, durability, and heat dissipation.

The PHATHEAD Y21 Racing Cylinder Head is designed to provide increased horsepower and torque, making it an excellent choice for racers and enthusiasts seeking to maximize the potential of their Yamaha YZ250. Its port design and combustion chamber geometry have been extensively tested and refined to optimize airflow and fuel-air mixing for improved combustion efficiency.

One of the standout features of this billet cylinder head is its large 41mm intake valves, which allow for a greater volume of air to flow into the engine, enhancing power output. The exhaust ports have also been optimized with a 35mm diameter and a 34mm exhaust valve, ensuring efficient exhaust gas expulsion.

The PHATHEAD YZ250-PHATHEAD-Y21 Racing Cylinder Head is equipped with a high-performance, fully adjustable camshaft and lifters system designed to offer optimal valve timing and duration. This allows for precise engine tuning, enabling you to tailor the power delivery characteristics of your Yamaha YZ250 to suit your riding style or racing conditions.

Additionally, the cylinder head features a high-performance, billet aluminum intake manifold and a high-flow fuel injector, ensuring optimal fuel delivery to the engine. The manifold's design promotes efficient airflow and even fuel distribution, further contributing to increased power and torque.

The PHATHEAD YZ250-PHATHEAD-Y21 Racing Billet Cylinder Head is also compatible with most aftermarket performance components, including high-performance exhaust systems and ECU tuning modules, making it a versatile choice for those seeking to take their Yamaha YZ250 to the next level.

In summary, the PHATHEAD YZ250-PHATHEAD-Y21 Racing Billet Cylinder Head offers Yamaha YZ250 owners an excellent opportunity to enhance the performance of their motorcycle. Its billet aluminum construction, high-performance intake and exhaust ports, adjustable camshaft and lifters system, and compatibility with aftermarket performance components make it a must-have upgrade for racers and enthusiasts alike.

The Phathead YZ250-Phathead Y21 racing billet cylinder head is a popular aftermarket upgrade for Yamaha YZ250 models produced from 1999 to 2026. This cylinder head offers several benefits, but it also comes with some drawbacks. Let's examine both.

1. Increased Horsepower: The Phathead YZ250-Phathead Y21 racing billet cylinder head is designed to provide more power. The billet design allows for better cooling, improved airflow, and increased compression ratio, resulting in more horsepower and better performance.

2. Improved Durability: The billet construction of this cylinder head is more durable than the stock cast iron head. It can withstand the high temperatures and pressures of racing and provide longer-lasting performance.

3. Customizable: The Phathead YZ250-Phathead Y21 racing billet cylinder head is highly customizable. You can choose different ports, jet sizes, and other modifications to suit your specific racing needs.

1. Cost: The Phathead YZ250-Phathead Y21 racing billet cylinder head is a significant investment. The cost of the head alone can be quite high, and you may also need to purchase other parts, such as new jets or porting services, to get the most out of the upgrade.

2. Complex Installation: Installing the Phathead YZ250-Phathead Y21 racing billet cylinder head requires a fair amount of expertise. It's not a simple bolt-on upgrade, and you may need to purchase additional tools and services to get it installed correctly.

3. Potential for Engine Damage: If not installed correctly, the Phathead YZ250-Phathead Y21 racing billet cylinder head can cause engine damage. It's essential to follow the installation instructions carefully and ensure that all components are properly aligned and torqued.

The Phathead YZ250-Phathead Y21 racing billet cylinder head offers significant performance benefits, including increased horsepower and improved durability. However, it comes with some drawbacks, such as a high cost, complex installation, and the potential for engine damage if not installed correctly.

If you're a serious racer looking for maximum performance from your Yamaha YZ250, the Phathead YZ250-Phathead Y21 racing billet cylinder head may be worth the investment. However, it's essential to ensure that you have the necessary expertise and resources to install it correctly and safely. If you're unsure about your ability to install the head yourself, it may be best to consult a professional mechanic to ensure that the installation is done correctly. Additionally, be prepared for the high cost and potential for additional expenses during the installation process.

Details:

Condition Notes: The head is in good functional condition. Fits: Yamaha YZ250 / YZ250X WR250 1999 -2026, Included Insert/Chamber: Y21, Volume: 21.1cc Stock Compression, Fuel Requirement: Minimum 91 Octane Pump Gas, Hardware: Combustion chamber dome, outer shell, and a set of copper sealing washers o-rings. See final photo This minor cosmetic wear does not impact sealing, thread integrity, or engine performance. Fast shipping.

Used Phathead Racing Billet Aluminum Cylinder Head Kit. Please review the photos carefully before purchasing.

part #: yz250-phathead-y21 price

• $299.00

specifications cylindermotorcycleiz:

• for makes: Yamaha
• for years: 1999-2026
• brand: Phathead
• mpn: Yz250-phathead-y21
• engine type: 2-stroke
• type: Cylinder Head
• unit type: Unit
• machine type: Off-road Motorcycle
• manufacturer warranty: 1 Year
• material: Aluminum
• vintage part: No
• california prop 65 warning: True

seller cylindermotorcycleiz:

• city: Sutter Creek, California
• rating: 100.0%
• # reviews: 95

payments cylindermotorcycleiz:

• credit card: Diners-club
• other
• wallet: Apple-pay

returns cylindermotorcycleiz:

• policy: No Returns

general cylindermotorcycleiz:

• condition: Used
• Motorcycle Scooter Parts Accessories > Engines Engine Parts > Cylinder Heads

shipping cylindermotorcycleiz:

• cost: $0.00
• class: Standard
• transit: 5-12 Days
• type: Calculated
• service: USPS Ground Advantage
• carrier: USPS

offer cylindermotorcycleiz:

• quantity: 1
• best offers: True
• started: June 10, 2026
• sold: 0
• options: Ship-to-home
• availability: In Stock

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