Bore and Stroke
Bore is the diameter of the cylinder, and stroke is the distance the piston travels from the bottom to the top of the cylinder. Together, bore and stroke determine engine displacement.An engine where the bore is larger than the stroke is called "oversquare" or...
What does Bore and Stroke mean?
Bore is the diameter of the cylinder, and stroke is the distance the piston travels from the bottom to the top of the cylinder. Together, bore and stroke determine engine displacement.
An engine where the bore is larger than the stroke is called "oversquare" or short-stroke — it can rev to higher RPM and produces more peak power. An engine where the stroke exceeds the bore is "undersquare" or long-stroke — it produces more torque at lower RPM. A "square" engine has equal bore and stroke dimensions.
How riders should use this term
Motorcycle terms are most useful when they help you understand real riding behavior. When you see Bore and Stroke on a spec page, treat it as one part of the full motorcycle package, not as a number or feature to judge alone.
- Compare the term against the motorcycle category and intended use.
- Check related specs such as weight, engine size, seat height, braking system and suspension.
- Use the comparison tool if two bikes look similar on paper.
Bore and Stroke questions
What does Bore and Stroke mean on a motorcycle?
Bore is the diameter of the cylinder, and stroke is the distance the piston travels from the bottom to the top of the cylinder. Together, bore and stroke determine engine displacement.An engine where the bore is larger than the stroke is called "oversquare" or short-stroke — it can rev to higher RPM and produces more peak power. An engine where the stroke exceeds the bore is "undersquare" or long-stroke — it produces more torque at lower RPM. A "square" engine has equal bore and stroke dimensions.
Why is Bore and Stroke important when comparing motorcycles?
It helps riders understand how a motorcycle may feel, perform or behave in real use. The exact importance depends on the bike category and the rider's purpose.
Where can I compare motorcycles that use this term?
Use the MotoLibrary specs database, advanced filter and comparison tool to see how this term appears across different motorcycles.