Well, these bikes benefit greatly from a gearing change, but only a small one. Leave the front sprocket stock (at 17T) and just go down 1 or 2 teeth on the rear. You have to keep in mind that you're only dealing with about a 50HP bike here. Go down more teeth on the rear than two and the bike won't pull to redline in 5th. You also effectively kill the bike's "fun factor", the great midrange "lunge" in the lower gears when you whack the throttle open. I've found one tooth down on the rear (34 stock to a 33) is perfect for an 18" rear wheel, two down (to a 32T) is perfect for a 16" rear wheel. This will reduce the RPMs at cruising speeds by 400 or 500 but won't kill the take-off power in the lower gears. So, if you search eBay, I think you'll find sellers offering 17-33 and 17-32 kits, maybe not including a chain but then you could just get the D.I.D. chain I mentioned separately. And the sprocket size change isn't big enough to need a shorter chain, you still will need a 104 link.