The Evo .45 runs like a bat out of h=ll with an APC 11x7 and the flywheel removed. You will love the engine then. The engine never needed that flywheel to be reliable. It still idles and runs as before. You won't notice it being gone, except for better performance. When I resurrect my trainer, I'm going to put a Tower muffler on the .45 and see what it does then.