RE: Gas engine conversion from Saitos?
The cylinder on the FG-30 has more cooling fins than the Saito 180.
Also on the FG-30 the intake manifold bolts on with three screws whereas the Saito 180 has a compression nut holding the intake manifold.
On the FG-36 they have a large intake valve and a small exhaust valve to make room for the big NGK CM-6 spark plug.
The FG-30 uses the same valves as the 120