The Small Engine Shop

Motorcycles => American V-Twin Motorcycles. => Topic started by: smallengineshop on January 28, 2020, 01:58:25 AM

Title: Was Harley Davidson The First To Have A PRoDucTion Final Drive Belt?
Post by: smallengineshop on January 28, 2020, 01:58:25 AM
Harley Davidson was one of two motorcycle manufacturers to produce the first motorcycle with final belt drive in 1980. The other manufacturer was Kawasaki. The 1980 Harley Davidson Sturgis model used a belt for both the primary and final drive and was marketed as the first motorcycle with "Twin Belt Drive." The Harley Davidson ad text in 1981 said "The Harley Davidson Sturgis is the first and only stock bike in the world with twin belt drive." The statement is true only because other motorcycle manufacturers were using gears instead of a chain for primary drive and had no reason to change to belt. The 1980 Kawasaki KZ440 was also manufactured with a final belt drive, and was marketing as the "Poly Chain." The Harley Davidson belts were constructed with Kevlar cords and the Kawasaki belt was constructed with aramid fiber cords. I believe Kevlar is also made up of aramid fiber's, but might have a different structure than the fibers used on the Poly Chain belt.

What I find most interesting about the Harley Davidson Sturgis model is I couldn't find any advertisements for the motorcycle until the 1981 model year even though having a final belt drive was a ground breaking achievement. 1980 was a rough time for Harley Davidson and it's parent company AMF, and the Harley Davidson brand was sold in 1981.

(http://www.thesmallengineshop.net/pics/commentary/1980 Kawasaki KZ440.jpg)
Parts diagram for the 1980 Kawasaki KZ440 rear wheel, rear hub, rear brake and final drive belt. Part #33 is the Poly Chain belt.