MadBoxer Brings Kickboxer Subaru WRX CAD Concept to Life

It all started years ago, in 2009, when we featured a series of Solidworks CAD drawings by Ian McElroy for a concept motorcycle called “Kickboxer.” The idea was to create a radical, but carefully planned design using the 2.5 liter engine from a Subaru WRX. The drawings were a big hit and quickly made their way all around the world until a friend sent one to Marcel van Hooijdonk down in New Zealand challenging him to “knock one up in the shed.” Marcel, a toolmaker by trade who manages a CNC and manual machine shop, is also an avid motorcyclist and he took the challenge seriously since it showed a combination of things he had always wanted to build, especially a center steering hub. Being a doer by nature, he got an engine case, some tires, spaced it out, stepped back, grabbed a beer and after some long hard looks decided, ... “yes, it’s doable.”

First order of business was to design and machine the front hub and then he proceeded to design the steering. It was also the first of many challenges from working within the New Zealand legal system so he could get the final design approved for road use. The design had to be changed several times as a result, he had come up with both a cable and a hydraulic steering setup that worked great and looked very tidy, but the mechanical system was the one finally given the green light, and so it went for a number of other parts of the bike. The original CAD drawings could have worked in a world where any design gets approved, but the finished “MadBoxer” you see here, is the one that’s now road legal in New Zealand.

The system here in NZ is not too bad, you forward your design at the beginning and a panel goes over it approving it or not and identifying any aspects you need to redesign. Then you re-apply and once you have approval you can start, but with inspections along the way. You can make changes as happens during builds, you always think of something you would like to do different which has to then go back to the panel and may need evidence to confirm your design i.e. stress calculations, loadings and load capabilities of items selected. At times its hair pulling but now it’s all done and 100% road legal.

The transmission is a stripped and modified two speed automatic with a torque converter, gear change is accomplished by pushbutton on the left handlebar. There are no foot operated pedals of any sort. Left hand lever is the rear brake, left hand button to shift, I have a hunch a new rider would want to go slow for a bit while he reprogrammed his brain, though it’s probably no more difficult, maybe even easier, than riding an old jockey shift Indian or Harley.

Tank and seat pads are from various Japanese bikes, front brakes and coil overs are Buell, but guards, swing arms, steering components, chassis and half the gear box are home made and if you look closely at these photos, you'll appreciate the huge amount of high quality work that went into those parts.

Getting it to start after all of the wiring was really difficult, all of the electrics and the lithium battery and capacitor are packed neatly under the seat and there was a lot of interference and Marcel says it probably took a good year before it started alone without the aid of a truck battery and jumper cables, which he says was one of those moments that brought a huge smile. The engine is straight out of a Subaru and was rebuilt before final installation.

All CAD design work, CNC machining and TIG welding were done by Marcel. The entire project took somewhere between 5 and 6 years with a few slow periods when designs were being changed, but persistence pays off and the bike you see here is on the road.

There were a lot of comments on the original Kickboxer post questioning the feasibility of the design, but everyone was impressed by the idea and many wondered if someone would, or even could, build it. Marcel just answered all of those questions.

This was, in Marcel’s words, a spare time shed project, but what a project! The Kickboxer CAD drawings inspired a real doer to look them over and say, “Yeah, I can do that,” and then go on to prove it. Marcel deserves a lot of praise for his ability to transform that CAD drawing into the finished bike shown in these photos. Great work, Marcel!