Cylinder head

The business end of the new DRP cylinder head.

Intake valve is smaller than the Powroll head but ports are a better shape, the valve has a reduced stem.

Head comes complete with valves, springs, and new double ball bearing camshaft.

I have some minor port work to do on the head and some minor machining to clean up the casting. I'll be lighting the rocker arms and replacing the DRP valve retainers with the Takegawa titanium retainers used on the Powroll head.

The DRP head is a nice quality piece of work, and at about $400 including valves, springs rockers and camshaft it's a pretty good deal.

Thanks to Richard at Ardjuna Racing in Holland for helping me acquire this part.


	Above and to the left is a view inside the intake port of the cylinder head used on the 99 season bike. Porting was done by Powroll. Image sizes do not indicate real size differences in the ports. These views just show the reconturing of the port and where the metal was removed.

	Above and to the left is the modified exhaust port. As you can see it was cleaned up and smoothed out nicely. At full valve lift both intake and exhaust flow was increase about 30%. Results were tested on a flow bench.