I've gotten heat in the past for speaking my mind on this. However, I feel there is no benefit in mounting a two stroke engine inverted, other then to get a lower needle valve to fuel tank level, where this is really necessary. To the contrary, it can and generally does make the engine difficult. Most of the really knowledgable engine people agree on this. Clarence Lee in particular feels it is only asking for flame outs and difficult running. Side mounting the engine is not difficult to do and makes for a reliable engine. All that is needed is re-drilling the mounting holes and filling in the old ones, not a difficult task.

People will tell you, if you do this, or that and change this, you can get a good running inverted engine. I say if you side mount, you don't need to pay any particular attention to anything to get a good running engine.

If your talking about inverted four strokes, these really do run o.k. upside down.