In a parallel twin-cylinder engine, the pistons move up and down in opposite directions. With a 360-degree crank, the pistons reach their top and bottom positions simultaneously. This creates primary vibration, which is a rocking force that can be felt through the handlebars and footpegs.
With a 180-degree crank, the pistons reach their top and bottom positions at different times. This cancels out the primary vibration, making the engine smoother.
Another advantage of a 180-degree crank is that it creates a more even firing order. With a 360-degree crank, the cylinders fire in a regular sequence (1-2-1-2). This can create an uneven sound and power delivery.
With a 180-degree crank, the cylinders fire in an irregular sequence (1-3-2-4). This creates a smoother sound and power delivery.
Overall, a parallel twin-cylinder engine with a 180-degree crank offers better primary balance and a more even firing order than a 360-degree crank. This makes for a smoother, more enjoyable riding experience.
