The Gold Wing's horizontally opposed six has been in production for just over a decade, and remains virtually unchanged. Age, however, has hardly left the Honda engine feeling long in the tooth, though it could be said that the new BMW mill has sharper, lighter, more compact teeth-24 of them, to be exact, compared to the Gold Wing's 12. And the number of valves per cylinder is only the beginning of the K1600's high-tech appeal. It's the lightest, most compact inline-six ever mass-produced for a motorcycle-less than an inch wider than the four-cylinder K1300GT it replaces. Redline for the inherently self-balancing 1649cc six is 8500 rpm, but everything from 1500 rpm to cut-off is fair game in any gear. This means you can hit freeway speeds in ..rst, loft the front wheel in third or throttle smoothly from a rolling stop in sixth. Power delivery is brilliant, and the sound of the engine is pure sex appeal- though unfortunately not from the saddle, where it's barely audible.