An engine modification for a specific chainsaw model, the Husqvarna 455 Rancher, involves increasing the cylinder’s bore diameter. This modification necessitates a replacement cylinder and piston, collectively known as a “big bore kit.” These kits are designed to increase the displacement of the engine. As an example, a standard Husqvarna 455 Rancher might have a displacement of 55.5cc, and a big bore kit could increase that to 58cc or more.
The rationale behind employing such a kit centers on enhancing the power output of the chainsaw. A larger displacement typically translates to greater torque and horsepower, enabling the saw to handle larger diameter logs and denser wood types more efficiently. Historically, these kits have been popular among users seeking to upgrade their existing equipment without the expense of purchasing a completely new, more powerful chainsaw. The upgrade can extend the useful life and performance of the original equipment.