An engine modification package designed to increase the displacement of a Yamaha TTR90 motorcycle engine. This typically includes a cylinder with a larger bore diameter and a matching piston. For example, a standard TTR90 engine might be increased from 89cc to around 110cc or more using this type of modification.
The implementation of such a component offers a performance enhancement to the motorcycle. The larger displacement generally results in increased power and torque output, particularly at lower engine speeds. This can translate to improved acceleration and hill-climbing ability. Historically, enthusiasts have sought this type of upgrade to improve the overall rideability and competitiveness of their machines in recreational or racing applications.
