From 1936 to the 1947 the production of Bigtwin is supplied with knucklehead 1000 and 1200 cc. engine.
With the advent of the engine 1200 cc. the Factory decided to adopt 16” rims and tires.
From 1948 to 1966
In the 1948 Harley Davidson Motor Co. introduced the new Panhead engine. Only the 1948 production was built with Springer front fork.
In the 1949 was introduced, as a prototype, a new front end with hudraulic system. For the first time Harley Davidson Motor Co. assigned a name to the model, in this case the name came from the forks: Hydra
In the 1958 started the production of a new model that substituted the Hydra Glide, the new one is called Duo Glide which means the use of the new frame with rear shocks
absorbers to male driving more confortable compare to the old rigid frame.
In the 1965
debut the Electa Glide model, the frame was edited to insert a bigger battery, 12 volts, and also the starter housed between the transmission and the oil tank.
From 1966 to 1969
In the 1966 Harley Davidson Co. edited the Classic Electra
Glide with a new shovelhead engine. Essentially same look with small changes as the position of the front drum brake that move from the left to the right side of the bike!
From 1970 to 1984
The first year of the Boat Tail was supplied in "Sparkling America" color, white with blue and red stripes.
1972 Harley Davidson add six more colors to chose from.
1973 Harley Davidson Motor CO. dismiss the drum brakes system and adopt the new disc brakes system, from now even the FX series
came with electric start beside the kickstar.
On 1977 the company introduced the Low Rider, derived from the FX base, they add a second front disc brake, alloy rims, lower seat from
the ground, strait handlebars (Dragbar) and stratched fork tubes.
1980 Harley Davidson Motor CO. introduced the FXB80 Sturgis, where "B" is for belt, a fine limited edition due to the experimental
changes made. On the FXB was replace the primiry and secondary chains with belts.
Inspired from classic choppers on
1980 the company disigned a new model. Using a bobtail rear fender, 5 gallons gas tank and a 21 inches front wheel installed on FL
stretched front end with 41mm fork tubes, the FXWG Wide Glide intruduced on the market a new bike style since today available.
FXDG is the last version of FX serial with Shovelhead engine and old style frame. "DG" is for Disc Glide. This bike close the
production of classic models.