Twintrax Custom FacebookTweetPin TwinTrax by the German Motorcycle Authority. The TwinTrax uses dual Harley-Davidson S&S Evolution engines. FacebookTweetPin Related Posts Fat Tire Lineup | Custom Built Chopper Motorcycles American Bagger | Motorbike Sweet 16 Chopper Green Chopper With Hangers Brass Balls Bobber Rocking Red Wheels Old School Rigid | Motorcycle