Honda 90 V-twin

A V-twin is a two cylinder internal combustion engine where the cylinders are arranged in a V configuration.

This arrangement is common on motorcycles, the engine can be mounted in transversal position like on Harley-Davidsons, Ducatis and many recent Japanese motorcycles. The longitudinal V-twin as seen on Moto-Guzzis and some Hondas is less common. This position is well adapted to its transmission shafting, but has the disadvantage of causing a torque reaction that tend to lean the motorcycle on the side.

The most obvious configuration for a V-twin is a 90 angle, but others angle can be seen like the 45 Harley-Davidson, the 75 Suzuki and the 60 Aprilia.

A 90 V-twin can achieve perfect primary balance but has some secondary imbalance. The 90 V-twin should be viewed as an alternative to the flat-twin configuration. The flat-twin is perfectly balanced.