BSA 68-0704 Thunderbolt Cylinder Head A65T 68-704

( Brand: Bsa ), ( Manufacturer Part Number: 68-0704 ), ( Part Type: Cylinder Head ), ( Vintage Part: Yes )

Review BSA Thunderbolt Cylinder Head fits A65 650 1967

The BSA 68-0704 A65/A65T cylinder head is a crucial component for the classic motorcycles BSA Thunderbolt models manufactured between 1967 and 1970. This head is specifically designed for the A65 engine, which was a popular choice during that period.

This cylinder head is constructed from high-quality aluminum alloy, ensuring durability and reliability. It features a hemispherical combustion chamber design, which offers improved air-fuel mixture and increased power output. The head also includes two valves per cylinder, with a diameter of approximately 31mm, and a valve angle of approximately 34 degrees.

The exhaust ports on this cylinder head are designed to provide optimal exhaust flow, ensuring maximum efficiency and performance. The head also includes spark plug threads, which are threaded to a standard size of M18x1.5, making it easy to replace the spark plugs when necessary.

Additionally, the BSA 68-0704 A65/A65T cylinder head includes a thermostat housing, which allows for the installation of a cooling system thermostat. This feature helps maintain an optimal engine temperature, ensuring consistent performance and longevity.

The cylinder head comes with gaskets and hardware necessary for installation, making it a complete kit. It is important to note that prior to installation, the cylinder head should be inspected for any signs of damage or wear, and the engine should be in good running condition. Proper installation and maintenance are crucial to ensure the longevity and optimal performance of the BSA Thunderbolt motorcycle.

Overall, the BSA 68-0704 A65/A65T cylinder head is a must-have for any BSA Thunderbolt owner looking to restore their classic motorcycle to its original glory or to improve its performance. This high-quality component is sure to provide years of reliable service and enjoyment on the open road.

Pros and Cons of Buying a BSA A65/A65T 650 Thunderbolt Cylinder Head (Part No. 68-0704)

The BSA A65/A65T Thunderbolt motorcycle was a popular British bike in the late 1960s. Its high-performance 650cc engine made it a favorite among riders. If you're considering purchasing a new cylinder head (Part No. 68-0704) for your Thunderbolt, here are some pros and cons to help you make an informed decision.

1. Improved Performance: A new cylinder head can lead to better engine performance. This includes increased horsepower, torque, and improved fuel efficiency. With the BSA A65 Thunderbolt being a high-performance bike, upgrading the cylinder head could potentially enhance its power and speed.

2. Durability: A new cylinder head is generally more durable than an old, worn-out one. This means fewer repairs and maintenance costs in the long run. The BSA 68-0704 cylinder head is designed to provide excellent service life and reliability.

3. Better Compatibility: A new cylinder head ensures better compatibility with other engine components. This can help prevent potential issues that may arise from using mismatched parts.

4. Enhanced Safety: A well-maintained engine is safer than one with worn-out parts. Installing a new cylinder head can help ensure the safety of both the rider and others on the road.

1. Cost: A new cylinder head can be quite expensive, especially for vintage motorcycles like the BSA A65 Thunderbolt. You may want to consider the cost of the head against the potential benefits and the overall value of the bike.

2. Installation Complexity: Installing a new cylinder head can be a complex and time-consuming process. It may require specialized knowledge and tools. Additionally, incorrect installation could lead to significant damage to the engine.

3. Availability: Finding a new cylinder head for a vintage motorcycle like the BSA A65 Thunderbolt can be challenging. It may require searching through various sources, including dealerships, online marketplaces, and aftermarket manufacturers.

4. Potential Compatibility Issues: While a new cylinder head should generally be more compatible with other engine components, there may still be some compatibility issues. These can include differences in thread sizes, gasket materials, or other aspects that require careful attention during installation.

The decision to buy a new cylinder head (Part No. 68-0704) for your BSA A65/A65T Thunderbolt motorcycle depends on various factors, including your budget, the condition of your current engine, and your desire for improved performance. While a new cylinder head can provide several benefits, including improved performance, durability, and enhanced safety, it also comes with drawbacks, such as high cost, installation complexity, availability, and potential compatibility issues.

If you're considering purchasing a new cylinder head for your BSA A65/A65T Thunderbolt, carefully weigh the pros and cons and consider your specific situation. If you have the budget, the time, and the desire for enhanced performance, a new cylinder head could be a worthwhile investment. However, if you're on a tight budget or are unsure about the installation process, you might want to consider other options, such as rebuilding your current cylinder head or seeking professional advice. Ultimately, it's essential to ensure that any modifications you make to your motorcycle prioritize safety and reliability above all else.

Details:

One fin has been repaired, See photos.

part #: 680704 prices

• $109.99-$389.99

specifications cylindermotorcycleiz:

• for models: A65, 650
• for years: 1967
• brand: Bsa
• mpn: 68-0704
• part type: Cylinder Head
• vintage part: Yes

payments cylindermotorcycleiz:

• credit card: Discover
• wallet: Apple-pay
• other

general cylindermotorcycleiz:

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

seller cylindermotorcycleiz:

• rating: 100.0%
• city: Denver, Colorado
• # reviews: 554

shipping cylindermotorcycleiz:

• class: Standard, Economy
• carrier: USPS, UPS
• type: Calculated
• service: USPS Ground Advantage, UPS Ground Saver
• transit: 4-8 Days
• cost: $12.27

offer cylindermotorcycleiz:

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

returns cylindermotorcycleiz:

• time: 30 Days
• policy: Returns Accepted
• paid by: Seller

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