The R03 is a 7 port engine based on a 14mm crankshaft, it is basicly a Kangaroo with JP his own specs.

There are 2 versions, the 1st productions had a CNC piston which did not have a long live but for a long time after that it did come with the microcasted piston, you can hear the difference in piston when turning the engine arround on the flywheel. The microcasted piston makes a more cracking sound you should have heard with the R09 as well.