you lose a bit more than that.. if you push a 4 stroke engine past it's redline, the valves start bouncing ie not keeping up with the cams and pistons... not only does this cause erratic fuelling & nasty things like live fuel going into the exhaust cos both inlet and exhaust valves are open at the same time, it makes the valves bounce - usually resulting in an undesired valve/piston interface and yer engine letting go spectacularly...