I've just got a Nova m.12 from another racer, and had some problems tuning it. It would either run so rich it spurted fuel from the pipe, or so lean it would get very hot...there was no happy middle ground. Either way it had very little power. I opened it up to find a sleeve installed backward, IE the top edge of the sleeve had been cut with a dremel to fit the locating pin....the sleeve was for an engine with the pin on the other side! The exhaust port does line up very close to perfect, maybe .5mm off at most. The sleeve fits the block a touch looser than any of my other motors as well. Finally the crank has some sort of goo in it to create a fuel ramp which is now flaking off, am i correct to assume this engine did not come with these "mods?"