What does the “”RAVE” or power valve adjustment do?
The red knob on the back of the cylinder of Rotax Max senior engines adjusts the RPM at which the power valve opens. Without getting too technical, the height of the exhaust port relative to piston travel, helps determine the power curve of the engine. When the power valve is closed, the exhaust port is “lower” and the engine delivers more power at a lower RPM. When the valve is open, the exhaust port is “higher” and the engine delivers more power at higher RPM. There are many philosophies as to what is the best setting and if it should be adjusted frequently or not at all. It is not a purely linear tradeoff however. Our dyno and track testing tells us that extreme settings in either direction have a detrimental effect on peak power as well as the characteristics of the overall power curve. The best rule of thumb is to set the RAVE valve to open at 7,500 rpm.
