There is no bike on the road that looks like a Harley-Davidson. Over the manufacturer's century-long history, the look of the Harley has changed and the true enthusiast can tell the year of a bike at a glance. One of the most obvious clues is the distinctive Harley engine.
For twenty years, Harleys got their look from the Shovelhead engine, the engine that many people even today automatically associate with the bike.
The End of the Panhead
In the mid 1960s, Harley Davidson motorcycles used the Panhead engine, so called because of the shape of the rocker covers. As the bikes got heavier they required engines with more power than the Panhead could deliver. In 1966, Harley introduced the next evolution of this engine design.
This new engine, like its predecessor, got its name from the shape of the rocker covers. The covers were shaped like coal shovels and these shovelhead parts inspired the Shovelhead engine's name.
The Shovelhead had more powerful cylinders and pistons and was meant to provide stronger acceleration to meet the demands of bikers of the day.
The engine had its drawbacks. It was more powerful but also heavier so did not give as much power as had been hoped. That weight also affected the bike's steering and could cause it to weave at top speeds.
Some of these shortcomings were because it had not originally been designed as a motorcycle engine. It was supposed to be used in an outboard motor but engineers discovered that it did not work well in humid environments, which is rather a significant drawback for a marine engine.
The Shovelhead Era
Although the Shovelhead was not perfect, it still provided a lot of power for the new generation of bikes.
Harley continued to improve the engine through its life. In the 1970s there were a number of changes made to the design of Shovelhead parts that resolved many consumer complaints about its performance.
However, the engine never became what bikers wanted it to be. Some of the reasons for this were the laws regulations that came out of the energy crisis of the 1970s. Harley was limited as to how much power they could give the engine.
One real improvement in Shovelhead parts was the FLH Electra-Glide Package, also known as the Police Option. Although this option made the bike harder for the amateur to maneuver, a skilled rider could get more power and speed.
The End of the Shovelhead
Despite Harley's efforts, this engine struggled to keep pace with the innovations that were sweeping the industry. Shovelhead parts such as oil management systems were considered archaic when compared to other engines and the machine fell out of favor.
Harley stopped producing the engine in 1984, although manufacturers still make custom engines in the same style. The Shovelhead was replaced by the Evolution engine that Harleys still use today.