The engine was designed as a nitro engine using considerably more oil in the fuel. It has no needle bearings or even bushings on the rod ends and runs steel on aluminum so it needs a lot more oil than they suggest.
It is also designed to run with methanol which gives a very good cooling effect and allows nitro engines to use less fin area for cooling. Gas engines run much hotter and have more cooling fin area so the engine has marginal cooling fin area and needs as much baffling as possible. It adds up to an engine that will not tolerate less than perfect running conditions unlike most gas engines which are hell for stout and run well under really abusive conditions.
Larry