www.HarleyHummer.com Antique Harley Davidson Hummer 165 Motorcycle Race at Davenport Iowa 2011. These are modified, American made, Harley Davidson “Hummers” on a 1 mile dirt flat track. Generally speaking, racers use a 1962 to 1966 2 stroke 165or 175cc Harley Davidson Pacer, Super-10, Ranger, or Bobcat engine, stuffed into a early pre-1962 Hard tail frame. These machines are heavily modified, utilizing a Mikuni carb, and expansion chamber exhaust, and turn twice as many rpm’s as the factory version. Hang on, and enjoy the ride!