Few motorcycle companies are as tied to specific machines as Harley-Davidson. Mention Harley-Davidson, and riders immediately think of icons like the Knucklehead, Sportster, or Electra Glide. Each changed the company in important ways, whether through engineering breakthroughs, cultural impact, or long-distance touring comfort. But the most influential Harley-Davidson ever built is not necessarily the most famous or the most beloved. Real influence is measured by what happens after a motorcycle arrives.

Source: https://www.topspeed.com/most-influential-harley-in-history/