Increased Power and Torque: The larger cylinder displacement provides more power and pulling force. Acceleration and top speed will significantly improve with a big bore kit, especially when combined with performance air filters, exhaust systems and engine tuning.

Enhanced Throttle Response: The increased airflow and higher engine compression result in an aggressive power delivery. The motorcycle will feel more responsive with immediate acceleration upon opening the throttle.
Greater Reliability: Premium big bore kits containing forged aluminum cylinders, billet steel connecting rods and high performance piston rings are designed to handle the higher stress from increased power. They provide reinforced strength and durability versus stock engine parts. With proper tuning and upgrades to the fuel and cooling systems, reliability can remain good even at high levels of added power.
Cost-Effective Performance: Big bore kits provide one of the most affordable "bang for the buck" upgrades for motorcycles. They can boost performance substantially for a reasonable price versus more complex modifications like turbocharging or supercharging. For hobbyists and backyard mechanics, big bore kits are easier to install with basic tools and skills.
Customized Power: Big bore kits are available in a range of cylinder displacements to provide varying increases in power based on individual needs and motorcycle models. Riders can choose a size that suits their specific performance goals and riding style. The kits can be installed in stages for gradually ramping up power. This flexibility allows for customized engine builds with the optimal combination of reliability and horsepower.
However, big bore kits also have some potential downsides:
Reduced Drivability: The increased power and throttle response may decrease drivability and make the motorcycle harder to control, especially for less experienced riders. Fuel economy can also drop significantly. This can be mitigated by selecting an appropriate bore size and proper tuning.
Higher Engine Stress: Although power and durability can increase with premium parts, the greater forces acting on the engine still reduce service life to some extent. More frequent maintenance and inspections are required. Oil changes and valve adjustments may need to be done more often.
Compatibility Issues: Big bore kits require machining the stock engine cases and may not fit all models. They can be difficult to install on some motorcycles and may interfere with other components. Extensive modifications could be needed in some situations. Profession al guidance is recommended for maximum compatibility and ease of installation.
In summary, big bore mechanical motorcycle cylinder kits provide a simple and cost-effective way to gain substantial increases in power and performance. However, the additional engine stress and potential reliability or compatibility issues mean that big bore kits may not suit some riders or riding styles. Proper selection and installation of the kits are important to maximize the benefits while maintaining drivability, safety and engine longevity.