When using another exhaust pipe, it will influence the opening of the power valve. With the VHM power valve adjuster with 2 stage spring, you are able to adjust the opening timing of the power valve easily with the screw. The first stage of the spring allows the power valve open very easily for a better and direct response. The second part of the spring keeps the power valve fully open for a maximum exhaust flow. The VHM power valve adjuster is made from high quality aluminum machined from solid.
The VHM power valve adjuster fits the VHM cylinder head (part number AA33112), VHM power valve base (part number DA31181) as well as the OEM cylinder head and power valve base.