The Evolution Engine of Harley Davidson | Bobber Blog


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The Evolution Engine of Harley Davidson

The Evolution Engine of Harley Davidson

Basically, the evolution engine which is commonly known as Evo is a V-twin engine which is manufactured by Harley Davidson Company for its popular bikes. This engine which is 45-degree air cooled came into the market by the year 1984. This engine came as a replacement for the Shovelhead engine till the year 2000. Specifically produced for the Harley Davidson Big V-twins bikes this engine was made in the 1340 cc displacement. By the year of 1999, this popular engine was replaced by the Harley Davidson Twin Cam 88, particularly in the Touring and Dyna model. Following this replacement was that of the Softail model motorcycles which happened in the year 2000. Replacing the ironhead Sportster engine, this engine was made in displacements 883 cc and 1200 cc specifically for the Harley Davidson Sportster model motorcycles. The particular displacement of 1100cc was made available till the year 1988.

The Evolution Engine of Harley Davidson

There was a period when the company of Harley Davidson was nearing bankruptcy. Many analysts even consider that the engine Evolution was the main reason for saving the company from the dreadful end. The change in its name might be strategy followed by the company in order to alter the image which was needed after the buyout from the AMF in the year 1981.


In order to reduce a significant amount of weight, the cylinder and the head of the Evolution Engine were supposedly made from aluminum. This, in theory, will be weightless in comparison with the cast iron design. Since aluminum is a fine thermal conductor when compared to cast iron, the air cooling effect was also greatly enhanced. Amongst all the made changes the aluminum heads along with the cylinders and the rocker boxes were the only significant part of the Evolution Engine.

The Evolution Engine of Harley Davidson

The embodiment of the Evolution engine in Big Twin and Sportster is majorly different. The Sportster Evolution stands in the same line with the other engines when it comes to the one cam per engine overhead value. This led to the single lobe four individual gear driven camshafts. Due to this design, the cam lobes are placed behind each other and the pushrods are placed parallel to the cylinder arranged in the set of pairs.

Other Bikes

Evolution was seen till the year of 2000 as a limited edition in the CVO FXR4 and FXR2 along with FXR3 models. Earlier to that this Big Twin made a major run for 15 years in the bikes FXR, Touring frames, Softail and Harley Davidson’s Dyna. In the last made limited edition the top part was considerably altered, but the main case saw only slight changes when in comparison with the Shovelhead engine.

The Evolution Engine of Harley Davidson

Since the Big Twin engine has its vertical plane of the cylinder rockets become directly perpendicular to the vertical plane of the cam lobes, there is a change in the appearance for these engines. Placed right above the crankshaft axis is the gear driven camshaft which a single four lobe one is used in the 1340cc Evolution.


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