it may be a tartan twin copy/ most of my experience has been converting the makita 4 cycle for airplane and heli use/ nice thing about the makita robin engine is that it has a oil pump in it .incorporated into the crankshaft with a sump clunk/ so the engine runs great in any position. if inverted however one needs to run a tube from the valve cover to the crankcase port on one side of the engine with a small tee pipe after the crankcase inlet to allow internal pressure to escape .