2006 Big Dog Motorcycles K-9, Clean low mile K9 comes with the $600 factory option passenger seat that has never been used - For the motorcycling enthusiast who?s ready to step out of the mass market pack, one breed has embodied the pinnacle of the custom American V-twin experience for over a decade: Big Dog Motorcycles. This year, we?re kicking it up another notch. Start with the introduction of the phenomenally rideable nine-foot long K-9, the benchmark of our Chopper line. And finish it with even more proprietary components that thrill your senses when you ride.