Engine Calculations
Tools and guides for calculating engine parameters such as cylinder displacement and compression ratio when rebuilding or modifying classic motorcycle engines.
Engine displacement can be calculated from the bore and stroke. Once you have the displacement you are one measurement away from calculating compression ratio. This page shows you how to do all of this.
Trigonometry can be used to convert crank rotation to piston drop. If you have the former, and would like the latter for setting up your engine, this article will show you how to do the conversion and even allow you to download a handy spreadsheet to do it for you.
Trigonometry can be used to convert piston drop to crank rotation. If you have the former, and would like the latter for setting up your engine, this article will show you how to do the conversion and even allow you to download a handy spreadsheet to do it for you.
This guide explains how to convert engine RPM into road speed using the gearing and rear wheel size of your motorcycle. By using the number of teeth on the engine, clutch, gearbox and rear sprockets together with the wheel diameter, you can calculate rear wheel speed and convert it into miles per hour. The article also includes a spreadsheet tool that performs the calculation automatically.
This guide explains how to convert road speed into engine RPM using the gearing and rear wheel size of your motorcycle. By using the number of teeth on the engine, clutch, gearbox and rear sprockets together with the rear wheel diameter, you can convert miles per hour into rear wheel speed and calculate the corresponding engine RPM. A downloadable spreadsheet is also included to automate the calculation.