Harley Evolution Engine Parts

Harley Evolution Engine Parts

The AMF era of Harley was a tumultuous time for the MOCO. The brand survived some very lean years, but their name was now being associated with being unreliable. The Shovelhead was a decent engine for the time, but the quality was not always there and at the end of its life, it was struggling to compete with the foreign imports. To save the company once again, Harley-Davidson needed to evolve. And in 1984, they did just that with the release of the Harley Evolution engine. The Evolution, also known as the Evo or Blockhead engine, was a complete revamp of the Big Twin.

In 1981, a group of HD executives and investors pooled together and bought the MOCO back from AMF with a mission to bring the brand back to its glory. To accomplish their mission, they knew they had to release a new engine that was much more reliable, had more power and would not overheat. It had to be “oil and air tight”. To do this, they needed to utilize new technologies, materials and manufacturing processes. The Evo was the first HD engine to be designed using CAD (Computer Aided Design), which allowed the engineers to be far more precise. HD’s new manufacturing processes included improved quality control and Materials As Needed inventory control, which allowed them to keep a tight rein on production as well as reduce overhead.

After seven years of design and engineering, the Evolution engine was a far cry from the mills of the past. The Evo proved to be much lighter, more powerful, and most importantly, more reliable and durable than any of its predecessors. One of the reasons for its success is the fact that the heads, cylinders and crankcase were all aluminum. This not only made the engine lighter, but also allowed for tighter tolerances, which increased power and cooling capabilities. With this setup, power and torque can be sustained throughout the powerband without suffering from overheating. The Evo was, indeed, much more “oil tight” than engines of the past, which made it far more durable. HD put it through rigorous testing to ensure that it could hold up to long hour, high mileage rides. They made a reliable coast-to-coast engine.

In the Big Twin models, the Evolution engine was offered only in the 82ci size. This displacement provided more than enough power and torque for HD’s bigger bikes. Horsepower increased 10% and torque increased 15% from the Shovelhead. Also part of the engine redesign was better lubrication and a reliable ignition system. Many Shovel owners reverted their ignition back to points because it was more reliable. With the Evo, the ignition system was made to last and be dependable when needed.

The Harley Evolution engine was well received and mass produced. With so many Blockheads still on the road today, the aftermarket is extremely strong for them. Whether you need to keep it maintained or mod it into a fire breather, you can find everything you need in the aftermarket. At Dennis Kirk, you will be able to find the largest selection of in-stock Evo parts. We are able to ship your parts the same day that you order, too. That way, you can get back on the road as soon as possible. And when your order is over $89, we will ship it to you for free. Use the Ride Selector at the top of the page to find all of the parts that fit your specific motorcycle. Also, feel free to contact our knowledgeable Tech Team if you have any questions on which parts and accessories are best for your ride.