Royal Enfield Spitfire 650 by Fast Fuel
For Busted Knuckles Build Off, Fast Fuel took the Royal Enfield Shotgun 650 and built something that makes an impression without losing sight of what a motorcycle is meant to do.
Named the Spitfire 650, this build was shaped by a simple idea from the beginning: motorcycles are made to be ridden. That principle guided every decision along the way. While plenty of customs lean heavily into showpiece territory, Fast Fuel chose a different path — creating a bike that is still road registrable, still reliable, and still grounded in real-world usability, even while pushing the styling into something far more expressive. Flame throwers aside, this is a motorcycle built to do what motorcycles are supposed to do.
That philosophy gave the project its boundaries, but they were boundaries chosen on purpose.
Rather than seeing function as a limitation, Fast Fuel used it as a framework. Inside that framework, the goal was to create something visually striking, full of personality, and unmistakably different, without losing the honesty of the base platform underneath it. The result is a build that carries presence, character and theatre, while still feeling like a machine that belongs on the road rather than hidden away in a corner.
The inspiration behind the project came from one of the most iconic machines ever built: the Supermarine Spitfire.
It draws on the aggression, mechanical beauty and purpose-driven design of the Spitfire, then reinterprets that mindset through the Shotgun 650. That approach gives the finished bike a clear identity without turning it into costume. It feels inspired by aviation rather than trapped by it, which is a big part of why the concept works.
Across the bike, that influence comes through in a series of carefully chosen details.
One of the standout features is the addition of afterburner-style flame throwers, which immediately give the bike a sense of theatre and attitude. They are one of the most eye-catching elements of the whole build and push the aviation influence into something playful, aggressive and unmistakably Busted Knuckles. It is the sort of detail that gives the bike a real sense of occasion without losing the build’s overall direction.
The military influence continues with the inclusion of ammunition case saddlebags, bringing another hard-edged and functional visual reference into the design. They reinforce the build’s mechanical and utilitarian feel, while tying neatly back to the Shotgun’s broader character and the Spitfire-inspired concept behind the project.
At the rear, Fast Fuel added a custom LED tail strip, helping clean up the tail section while giving the build a more resolved and contemporary finish. That sits nicely alongside a series of more tactile, hand-finished details elsewhere on the bike, including the hand-brushed bomber teeth clutch cover, which adds a direct visual link to classic wartime aircraft graphics and gives the motorcycle another layer of personality.
The finish of the bike also plays an important role in the overall result. Candy red powder-coated details bring contrast, energy and depth to the build, helping key components stand out without overwhelming the design. It is a measured use of colour that gives the Spitfire 650 a sharper, more deliberate identity.
The cockpit has also been refined through the use of internally wired handlebars, a detail that helps keep the front end cleaner and more cohesive. It is one of those modifications that may not shout the loudest, but it contributes a lot to the quality and finish of the bike as a whole.
The seating setup was another area where Fast Fuel added both character and comfort, fitting a sprung seat paired with a custom upholstered seat finish. Together, those details help give the Spitfire 650 a stronger custom identity while still supporting the build’s broader emphasis on usability and rideability.
That balance between expression and restraint is what makes this project stand out.
Fast Fuel did not set out to reinvent the Shotgun 650. In their own words, the approach was to enhance the platform rather than replace it. The Shotgun already marked a clear step forward in Royal Enfield’s more modern design direction, and this build respects that.
That approach also feels well aligned with Royal Enfield’s wider ethos.
The Spitfire 650 stays connected to the original bike, while showing how much character can be drawn out of a platform with a strong concept and a clear hand behind it. It also taps naturally into Royal Enfield’s own military heritage, which gives the build another layer of relevance. The connection between inspiration and execution feels genuine rather than forced, and that helps the finished bike land with more authenticity.
For Busted Knuckles Build Off, that matters.
The best builds are not just visually loud. They have an idea behind them. They know what they are trying to say. With the Spitfire 650, Fast Fuel has delivered a custom that is distinctive, theatrical and full of personality, but still grounded in the core purpose of the motorcycle itself.
It looks the part. It carries a strong theme. And most importantly, it still remembers what a motorcycle is for.