Ok with my ported motor and Honda intake all the way around the lightend flywheel -5 ounces has made a huge difference it revs faster and it gives it a whole lot more bottom end with my Vforce reeds and then I installed the head and boy it made a huge difference it wasn't tht hard to kick over like the Vito's head but when the bike is running it is lime running a whole new bike more power everywhere by far the best mod on my bike besides my porting this head shocked me when I rode it and wow I would never run any other head again props to KOR another job well done best mod ever I highly recommend them