The Dark Rider first appears in Shadow the Hedgehog as an unnamed vehicle. It is shown in the game's intro, where it gets destroyed, and in Lethal Highway.
The bike appears to be a 2003 Harley Davidson XL1200 Custom Anniversary Edition with jet black paint, the G.U.N. symbol, and no exhaust pipes.
The vehicle appears to be a 2003 Harley Davidson XL1200 Custom Anniversary Edition, albeit with design differences, a new color scheme (black, red and yellow), and double-barreled vulcan cannons.
Sonic & Sega All-Stars Racing
The Dark Rider appears once more in Sonic & Sega All-Stars Racing as Shadow's vehicle. It looks practically identical to its appearance in Sonic the Hedgehog (2006), but it doesn't have machine guns (probably because the vehicles in this game don't have built-in weapons). Instead of the GUN insignia, it has the Black Arms insignia on its fuel tank.
Shadow is one of the four characters in the Sonic franchise in Sonic & Sega All-Stars Racing that rides a bike family vehicle. (the others being Big, Metal Sonic, Knuckles and Alex Kidd).
The Dark Rider also appears in the Sonic the Hedgehog comic series, debuting in Sonic Universe. It appears humorously on the cover of Sonic Universe #23 with Cream the Rabbit and Cheese the Chao riding it. Amy asks why Shadow even has a bike and he explains that all GUN Agents must be issued with a vehicle. Rouge points out that even though he doesn't need it, Shadow customised and maintains it himself, to which he admits, "I really like that bike."
The Dark Rider was made into a toy for the Sonic & Sega All-Stars 3" action figure series, coming with a Shadow figure with hands especially molded so that they could wrap around the handlebars of the bike, keeping him on it. The Dark Rider was also made into a radio-controlled toy with a working headlight.