Thursday, 2 May 2024

This five-cylinder Puch proves there’s no replacement for displacement

Custom five-cylinder Puch Maxi S moped
They say that there’s no replacement for displacement. By that logic, the best way to improve a single-cylinder Puch moped is to turn it into a five-cylinder Puch moped. At least, that’s Uwe Oltmanns’ theory.

Based in Northern Germany, Uwe is a moped enthusiast with an extensive resume. He’s a professional toolmaker who’s worked at Airbus, built hopped-up Opel street cars, and dabbled in drag racers. These days, he spends his time building vintage car engines from parts that he’s machined himself—mostly for pre-war BMW 328s.

Custom five-cylinder Puch Maxi S moped
He also messes with vintage mopeds—or, as they’re known around those parts, ‘MOFAs.’ “Due to the flat countryside near the North Sea, automatic MOFAs are a thing in Northern Germany, especially the Puch Maxi S and N from the 70s and 80s,” says Uwe’s friend, and the photographer who brought us these stellar images, Sven Wedemeyer. “So there’s a long-standing tuning scene in this region.”

“These were called MOFAs (short for ‘MOtor-FAhrrad,’ which is German for ‘motor-bicycle’), and usually had bicycle pedals. The dream of every teenager back then!”

Custom five-cylinder Puch Maxi S moped
To say that Uwe is passionate about mopeds is an understatement. To relive his youth, he organized a four-hour endurance race for classic MOFAs, with a makeshift circuit that ran laps around the local bar. “It was a huge success,” Sven tells us, “with 46 MOFAs and eight emergency calls to the hospital!”

The event became an annual thing, growing year on year until a custom show became part of the proceedings. And that was all the excuse that Uwe needed to build something outlandish.

Custom five-cylinder Puch moped
Uwe kicked things off with a 1976 Puch Maxi S moped—a humble 48.8 cc two-stroke with a one-speed transmission. But very little of the original bike remains. Uwe not only brought four more Puch engines to the party, but he also rebuilt the rest of the bike with a smorgasbord of interesting parts.

The Puch’s main frame was left intact, but the rear frame was hacked off and replaced with an angular handmade unit. Uwe turned to the suspension next—and then stumbled upon something truly special.

Custom five-cylinder Puch moped
Through sheer serendipity, Uwe managed to get his hands on a prototype rear swingarm that had been developed for Ralf Waldmann’s 1993 Aprilia RS 125 R Grand Prix racer. He worked his magic, modifying the single-sided swingarm to suit the Puch, and hooking it up to a hidden mountain bike shock via a handful of CNC-machined parts. A three-spoke magnesium wheel from PVM does duty out back.

Later on, Uwe snagged a set of race-spec WP Suspension forks, again from Waldmann’s 1993 Aprilia (they’re one of only 60 sets made). Uwe CNC-machined a set of yokes to attach them to the bike and then fabricated his own bar risers and grips. A set of streetfighter bars with aftermarket scooter levers sit up top.

Custom five-cylinder Puch Maxi S moped
For the front wheel, Uwe took a moped’s outer rim and machined a new inner section to match the PVM rear wheel. The brakes use Braking calipers with laser-cut stainless steel discs. An airbrush specialist company called Pfeil handled the bike’s heavily textured silver, gold, and black paint job.

The peculiar headlight is a custom part too. “Uwe had a vision at five in the morning after a long party,” says Sven. “So he started CNC-machining immediately, using BMW Z8 Prism technology. He went to bed after that, and was quite surprised the next day at what he had done.”

Custom five-cylinder Puch Maxi S moped
Sven is pretty blunt about the fact that, although Uwe’s Puch does run, it’s basically unrideable, thanks to the noise and heat that it emits. Each of the five two-stroke engines has been bored out to 70 cc, fitted with an upgraded round-slide carb and a fly clutch, and given a wide-open exhaust header. The bottom three motors are linked by a central shaft, with two separate belt drives connecting engines four and five.

To start the bike, Uwe spins the rear wheel to get the first engine going. Once that’s warmed up, each of the subsequent engines is unleashed one at a time by releasing their fly clutches with a wrench (see it in action here). With all five motors purring, the 350 cc Puch registers 127.5 decibels—and the only way to shut it off is to pull all five spark plugs.

Custom five-cylinder Puch moped
This sort of insanity is nothing out of the ordinary for Uwe. He’s also built a 70 cc Puch moped with a crank-driven supercharger, and he’s currently working on a V10 Puch with a longitudinal crank. We can’t wait.

Images and build info supplied by Sven Wedemeyer / Wheels of Stil

Custom five-cylinder Puch Maxi S moped



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