Los Angeles, CA – Actor Jason Momoa, best known for tough guy roles in Game of Thrones and Aquaman, was recently spotted posing on a classic 1940’s era Harley-Davidson Knucklehead motorcycle. The images showing Momoa’s signature long hair blowing in the breeze have gone viral, sparking new interest in these iconic pre-1950’s Harley bikes.

In the photos, Momoa looks cool and rugged while sitting atop a beautifully restored Knucklehead customized by Thunderbike, a German shop specializing in vintage Harley rebuilds. Momoa seems right at home on the vintage Harley, which harkens back to the early days of motorcycle culture.

Thunderbike, run by renowned builder Andreas Bergforth, is known for its faithful Knucklehead restorations just like the one Momoa rode. The Knucklehead engine was first introduced by Harley-Davidson back in 1936 and was produced until 1947 when it was replaced by the newer Panhead. But the Knucklehead name itself has lived on as these vintage bikes remain hugely influential in motorcycle culture.

The Knucklehead engine is named for the unique shape of its rocker boxes that resemble knuckles on a fist. These old v-twin engines have such a iconic look that the Knucklehead style has become synonymous with the classic Harley style. It’s easy to see why Sylvester Stallone chose to ride a Knucklehead in the 1979 movie Rocky II, instantly cementing it as a “tough guy” bike.

Thunderbike’s Knucklehead Project bike that Momoa posed on was built by Bergforth himself nearly a decade ago. He started with an original 1940’s Knucklehead and fully rebuilt and restored it from the ground up. Unlike some overly polished restorations, Thunderbike aimed to maintain the raw, worn-in feel of a well-ridden vintage motorcycle. There’s no mention of how many original parts remain, but the worn patina gives it an authentic look and feel.

The Knucklehead engine itself represents a pivotal era in motorcycle history. When Harley unveiled it in 1936 it featured a host of upgrades over previous models like overhead valves and stronger connecting rods. Combined with its muscular aesthetics, the Knucklehead gave Harley bikes performance to match their looks. It’s a powerful, torquey engine that defined the early Harley v-twin sound and feel.

For these reasons Knuckleheads have remained highly sought after by collectors, custom shops, and pop culture icons alike. Custom builders love starting with Knuckleheads because of their iconic styling. And the rumbling v-twin sound is immediately recognizable as an old school Harley. With its vintage styling and connection to American motorcycle history, it’s easy to see the appeal for guys like Jason Momoa who want to look cool.

Momoa clearly appreciated the chance to throw a leg over this classic Knucklehead custom, snapping selfies to share the experience on social media. For fans of vintage motorcycles, it was exciting to see this A-list celebrity enjoying the iconic bike. With his signature attitude and rebel style, Momoa brought out the cool factor of these Harley predecessors. Not just a relic of the past, Knuckleheads represent the American freedom and spirit that still lives on today.