Evolution Valves

Mike has gotten the Evolution heads back from DPR Engines machine shop and is getting ready to install the heads onto the cylinders. Although the machine shop has already performed a complete evolution valve job, Mike has disassembled one of the evolution valves in order to touch base and discuss valve protrusion as well as valve seat pressure. Mike is not looking to increase evolution valve spring pressure on this motor. He is not chasing performance on this particular build. He is only focused on building a solid, dependable motor. He projects many carefree riding miles before this motor will need to be looked at again.

Mike will be replacing the original evolution valve seals with better, premium valve seals. Mike lubricates the valve stem, slides it up through the valve guide, and holds the valve up in position against the valve seat. The evolution valve spring seat is installed and a temporary protective sleeve slid over the end of the valve stem to protect the sealing edge of the new valve seal. The valve seal is now carefully slid over the valve stem and pushed into position over the valve guide. The protective sleeve is removed.

Now, with the spring and top retainer in position, Mike uses his evolution valve spring compressor to compress the spring. Two keepers, or keys, are set into position and the spring compressor is removed. Mike gives the valve spring top a tap with a plastic mallet to verify that everything is assembled securely. He does this with the assembly facing away for safety. Prior to installing the heads, Mike reminds us the importance of inspecting front and rear exhaust studs. If any of these studs need to be repaired or replaced, it should be taken care of now, before the heads are installed.

With the metal head gaskets in position, the heads are installed and evenly torqued to spec.

Thanks again to Nick at DPR Engines for the rush job and delivery so we can get this video out.

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