“Warthog” Ironhead Sportster Drag Bike

Built for War, Best in Show: 70s Ironhead Harley Drag Bike…  

In 1957, Harley-Davidson released the Sportster in response to stiff competition from British rivals like Triumph and Norton, whose twins were lighter, faster, and more modern than Harley’s K-series flatheads or OHV Panheads. The new engine, dubbed the “Ironhead” for its cast-iron cylinder heads, would power the Sportster until 1985. 

While it’s strange to think of it today, the Sportster was at one time the fastest mass-produced motorcycle available to the average enthusiast. Consider Cycle World‘s review of the XLCH in 1962:

“The Harley-Davidson’s claimed 55 bhp begins to sound very believable, for it is clearly the fastest mass-produced motorcycle we have had… It is big, powerful, and goes in a manner that will make hair grow on your chest (if you’ve already got the hair, it will part it down the middle). It is, above all else, the fastest thing the expert rider is likely to find for sale, anywhere, and when that is said, anything more is superfluous.” –Cycle World, 1962

Fast forward to present day, and the Ironhead has been transformed into just about every style of bike possible: bobber, chopper, cafe racer, scrambler, tracker…you name it. What’s more, a number of racers built drag bikes around the engine, with various gas-burning Ironheads reported to run low nines and high eights — not bad for an engine designed in the 1950s!

This 70s-style Ironhead drag bike, nicknamed the “Warthog” or “Celeng” (Indonesian for boar), comes from our new friend Daniel, a film camera technician and director from Indonesia. Daniel built his first café racer back in 2012, and later restored a BSA ZB31 350cc with the help of his friends from the custom workshop Sinner & Co.

“Just like my passion for vintage cameras with their gears and springs, vintage British and American bikes also fascinated me with their mechanical beauty… I started sketching and measuring all the custom parts, then doing the lathe and milling work in my friends’ workshops. From that point, I began refining the Warthog concept.”

The frame and triple trees are from a 1973 Ironhead, but everything else is custom. The engine is a ’71 modified with dual-plug heads, dual XR750-style intakes, and twin Keihin FCR 37 carbs — trick! On the electrical side, there’s a set of dual Dynatek coils, Dyna electronic ignition, and a lightweight Lifepo4 battery in a 3D-printed holder.

The gas tank is made from 304 stainless steel in a dual-cylinder style popular on vintage drag bikes, and there’s a shortened “lunchbox”-style oil tank tucked behind the engine. The rear hub is also made from 304 stainless, with a Toyota fluid drum rear brake and Wagner Lockheed 3/4″ bore rear master cylinder. Up front is a custom hub and dual front drum brake, so this drag bike can actually stop. The cockpit is decked out with old-school Beck grips, and there’s a right side foot shifter and brake.

The Warthog is rolling on a 19-inch front wheel with striped tire and an 18-inch rear with a meaty MH Racemasters rear drag slick. The bike looks incredible, and it makes an even stronger impression from the saddle.

“Just like its name, it feels like riding a boar. Trimming all the heavy parts made the bike lightweight, which also increased the vibrations from the solid-mounted Harley engine.”

There seems to be a real sense of community in the Indonesian custom world, and Daniel is quick to thank all his friends who contributed time and parts to make the Warthog a reality.

“My friends’ support made it possible. This bike truly belongs to the people.”

The Warthog took home Best in Motorshow in the Big Dawg >500cc class at Custom War 2025 on Bali — congrats, Daniel! What a stunning, nostalgic drag bike that takes us right back to the gas-class racers of yesteryear.

Below you’ll find our full interview with Daniel about the build, along with more shots from photographer Rahmat Baskara. Also, if you’re interested in vintage drag bikes, we highly recommend you join the Facebook group started by our buddy Kevin Busch, whose “Born Again” Triumph drag bike we featured a few years ago: Vintage Drag Bikes of Days Gone By.

Ironhead Drag Bike: Builder Interview

• Please tell us a bit about yourself, your history with motorcycles, and your workshop.

Hello, my name is Daniel from Indonesia. I’m an unauthorized Leica film camera technician and a digital ads/documentary director.

My first build was a Honda GL150 in a café racer style, which I worked on back in 2012 during college with a friend. After selling my Honda in 2012, I made a promise to myself: the next vintage motorcycle I would purchase had to be powered by a European or American engine.

I never expected the opportunity to come, but in 2019 I was able to buy my first vintage motorcycle — a BSA ZB31 350cc. Long story short, I finished restoring the ZB31 at my friends’ workshop, Sinner & Co. Just like my passion for vintage cameras with their gears and springs, vintage British and American bikes also fascinated me with their mechanical beauty. I built the ZB31 engine at home with the help of many friends. From there, my journey of tinkering with motorcycle engines and making my own bike parts truly began.

I started sketching and measuring all the custom parts, then doing the lathe and milling work in my friends’ workshops. From that point, I began refining the Warthog concept. 

• What’s the make, model, and year of the donor bike?

1971 Harley Davidson Sportster (Ironhead).

• Why was this bike built?

Personal.

• What was the design concept and what influenced the build?

1970s drag bike. In my free time, I often research on Harley forums and come across threads about ignition efficiency, XR-style Harleys, and building reverse-headed Harleys, among other topics.

• What custom work was done to the bike?

• All parts are custom, except the main-frame and triple trees.
• 1971 Drag Custom Ironhead
• Dual Independent Intake, XR Style with dual Keihin FCR 37
• Dyna 2000i Electronic Ignition
• Dual Dynatek Dyna Coil 3 ohms
• Modified to 4 Spark Plugs
• Shortened Lunch Box Oil Tank to fit in dinamo starter space.
• SS304 Barney Benson’s style front forks.
• Custom Rear SS304 Hub, and Toyota’s fluid drum brake.
• Custom front hub and dual drum brake.
• Lifepo4 batt, custom 3D-printed battery tray.
• 18 inch MH Racemasters back tire, 19 inch Taiwanese stripes front tire.
• TCME Taillight for ignition check light.
• Original 73’s Ironhead Frame, Original 33.4mm Triple Tree.
• Beck Rubber Hand Grip.
• SS304 Gas Tank.
• Foot Control : Right side Brake and Shifter.

• Does the bike have a nickname?

Yes, WARTHOG / CELENG (Boar in Indonesian).

• Any idea of horsepower, weight, and/or performance numbers?

Not yet.

• Can you tell us what it’s like to ride this bike?

Just like its name, it feels like riding a boar. Trimming all the heavy parts made the bike lightweight, which also increased the vibrations from the solid-mounted Harley engine.

• Was there anything done during this build that you are particularly proud of?

My friends’ support made it possible. This bike truly belongs to the people.

• Is there anyone you’d like to thank?

To all my friends and everyone who contributed parts to this bike.

Follow the Builders

Builders: @dnaielpnuormo @sinner_and_co @gaztuned @soleh9052
Photographer: @rahmatbaskara

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