00:00 Intro 00:35 Motorcycle and car applications and firing intervals 05:00 Acceleration, Velocity and Force 07:58 Primary balance and vibrations explained 12:22 180° and 360° twins primary balance ...

Shaking engines aren’t desirable, so we try to remove these forces. It’s easy to understand that as the piston comes to the top and stops, it sends an upward force, called a primary force.