A lot will depend on the particular engine, and the application. I'm removing all of that on my street cruiser Tec OHM110 since it's cylinder is upright and the exhaust port is on the side so it gets some cooling. Flatties and slopers may not fare as well, unless turned around and run through a gearbox that reverses the rotation. Or, changing the cam drive from counter-rotating gears to same-spin chain and sprockets like a Honda G-unit so the crank can spin backwards once the flywheel and recoil have been set up for it.