When using another exhaust pipe, it will influence the opening of the power valve. With the VHM power valve adjuster with 2 stage spring (partnumber DA31153), 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 full 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 can be used with the VHM cylinder head and VHM power valve base as well as the OEM cylinder head and power valve base.