What does increased volume do to engine torque?
Crankcase compression is increased and this consequently shifts maximum torque to higher RPM and enables achieving higher speed (under condition that the engine has enough power). This can sometimes lead to narrowing the usable RPM range and decreased engine flexibility. In other words, if RPM drops below usable range under heavy load, performance decreases, for example when riding in strong wind or up a steep hill. Problem of the “torque hole” can be compensated with an expansion chamber designed for high torque at mid RPM or/and with a boost bottle.
