DOING THE BOXER BEAT
When images appeared of Motorino Diavolo’s Vespa twin they were dismissed as photoshopped nonsense but, as Stan discovered, it’s real and this boxer packs a punch.
Based in Fürstenfeldbruck, in the heart of Bavaria, Christian Mühlbauer is an engineer at the top of his profession. The founder and CEO of IB-Ideenbau, Christian is wary of listing the clients he’s worked with, but the company specialises in producing technical exhibits and prototypes for high-end projects. To operate at that level the company needs access to the very best software and CNC machinery, so this is no back street operation. Fortunately for us, Christian has a passion for pushing scooters to the very limit and he’s created a separate brand for his scooter projects, ’Motorino Diavolo’.
“About 30 years ago a friend of mine bought a PX,” explained Christian. “He removed the panel and showed me the engine. I asked to see under the other panel and when he revealed a spare wheel it seemed like such a waste. I didn’t have the skills to do anything about it at the time, but was interested enough to buy my own PX.” Predictably, this didn’t stay in standard trim for long and soon Christian’s stable grew to include a smallframe. “I enjoyed those Vespa years,” he said, “but I eventually sold both scooters to concentrate on building Hot Rods.” Over the next couple of decades Christian rose to the top of his profession, whilst simultaneously gaining a reputation for building innovative and high specification Hot Rods. “A few years ago I saw the guy I’d sold the smallframe to and he told me it was still in his garage. I offered him €500, exactly what I sold it to him for. He accepted and my interest in Vespas was renewed.”
Having re-familiarised himself with Vespas on the smallframe, Christian went on to build an Acma wideframe, but his mind kept returning to the empty space under the PX’s side-panel. Around 18 months ago Christian decided to fill that void, and as we can all see the result is stunning.
Template-less
Christian had no template to work from and the Vespa’s monocoque chassis ruled out several engine configurations. Although the engineering is complex, Christian’s a master of explaining things to the casual observer. “We have two linked engines,” he began. “The ‘right engine’, which is a standard Cosa unit, and the ‘left engine’, which is the new component. The right engine case is untouched. In fact, the whole conversion can be reversed very quicklyquickly. The major change is to the clutch, which is a completely new unit manufactured by Kingwellen. This stands proud of the crankcase and a sprocket has been fitted around its outside edge, a little like the flywheel on an electric start Vespa. This sprocket enables me to link the left engine with a vibrationdamping Rotax coupling. The left engine uses a modified PX80 casing and the adaptors are all fitted using the right case’s existing fastening points. Other than the throttle cable, it’s a relatively straightforward matter to set the engine up, particularly as it still uses the Cosa’s ignition.”
The result is a transversely mounted, horizontally opposed, air-cooled twin. Although it uses separate crankshafts, this is effectively a ‘Boxer’ engine of the type made famous by VW and Porsche. Visually it’s an unusual concept as the left engine has been rotated through 180 degrees so that it now faces rearwards. These engines use two Quattrini M244 kits, but theoretically any top end that bolts on to standard Piaggio cases could be used. Transmission is also taken from a Cosa, but one of Christain’s early developments was a sequential gear shifter and this has been fitted to the Boxer.
Obviously the Boxer won’t just bolt into a standard frame, and this is where the reverse facing left engine design reaps dividends. A donor frame provided the engine cut out and this was welded into the frame. The tank also needed adapting, but there’s only a loss of around half a litre in volume. All this engineering is wrapped in a package that looks like a standard PX. There’s even a spare wheel cover hiding the left engine. Parked in a line of scooters, it looks tidy, but unremarkable. Exactly the effect Christian sought.
Motorino Diavolo may be new to the arena, but the Boxer and its superb engineering demonstrate that they’re capable of punching far above their weight.