The use of a different muffler affects the opening of the power valve. Thanks to the VHM power valve adjuster with compression spring, you can easily adjust the valve opening time by means of a screw. This adjuster is made from high-quality aluminium.
The VHM power valve adjuster fits the VHM cylinder head (AA33112), the VHM power valve base (DA31181) and the OEM cylinder head and power valve base