Fearsome Four: Clymer-Münch Mammoth

Though the honor for being first to propose an across the frame inline 4-cylinder motorcycle engine must go to Carlo Giannini and Piero Remor for their 1923 Rondine race bike, it would take another 45 years for the format to find its way into a street bike. And it wasn’t Japanese.

That bike was the creation of German Friedl Münch. Born in 1927, Münch was an engineering prodigy, developing his skills in his father’s gas station workshop and Horex dealership in Nieder-Florstadt, Germany. Completing military service as a technician in the Luftwaffe, Münch also attended technical school, where he won a scholarship and two achievement awards. By 1948, Münch had completed his training in mechanical and electrical engineering, and soon opened his own shop repairing and tuning Horex motorcycles.

A rider since age 6, Münch intended to prepare race bikes for his own use. He built a 500cc Horex-based special with a double overhead cam cylinder head and dry sump lubrication, but a serious crash ended his hopes for a racing career. In other racers’ hands, though, the Münch-Horex specials were so successful that Horex offered Münch a job in their racing development department — which he at first declined. But when Münch’s own business failed in 1955, he changed his mind.

Münch beginnings

When Horex ceased production in the late 1950s, Münch acquired a stash of Horex parts and tools and set about designing and building his own motorcycles based on Horex’s overhead cam 400cc Emperor twin, bored out to 500cc. But Münch dreamed of creating a sophisticated motorcycle with supreme performance — what we would come to know as a “Superbike.”

His goal was an inline double overhead cam 4-cylinder with state of the art cycle parts. Münch had even designed an engine around an experimental Horex cylinder head with two Emperor cylinder blocks. But when a friend showed him the new 4-cylinder NSU Prinz 1000 car around 1963, Münch saw that a simpler solution was at hand: He would build his superbike around the NSU’s lightweight, air-cooled, 40 horsepower engine.

The NSU engine was a 996cc inline four with an aluminum cross-flow cylinder head and chain-driven single overhead camshaft. Münch mounted it transversely in a tubular steel frame of his own design similar to the best then available — the Norton Featherbed — but stronger. To transfer power he used a modified Horex transmission driving the rear wheel by chain. Münch also tuned the engine for more power.

At the front, Münch used a conventional 40mm telescopic fork of his own design carrying a massive 250mm twin-leading-shoe drum, also of his own design. To keep weight down he cast the drum in Elektron magnesium alloy with an iron liner. He also used Elektron for the steering stems, the oil pan and the primary/transmission housings.

Initially, Münch used conventional 18-inch spoked wheels front and rear, but in spite of using spokes as big as 5mm diameter, the torque from the NSU engine would eventually strip the spokes out of the nipples. Regardless, this was the first Münch-4 shown to the press in 1966, when it quickly acquired the name “Mammut,” or Mammoth.

Enter Floyd Clymer

A second prototype incorporated several improvements and modifications. To overcome the spoke stripping issue, Münch designed a new rear wheel with an integral 250mm drum brake cast in Elektron. A fully enclosed chain case, also cast from Elektron, formed one arm of the swingarm rear suspension.

Also cast from Elektron was a new rear body section incorporating the fender, and a headlamp cowling holding a pair of NSU TT car headlights. In spite of all the magnesium alloy used, the second prototype still tipped the scales at close to 600 pounds dry — but it had phenomenal performance for the time, taking just 4.5 seconds to reach 60mph and hitting 112mph after 20 seconds.

This was the bike shown at the Cologne motorcycle show in the fall of 1966, causing something of a sensation. NSU agreed to supply Münch with engines, and Münch went into limited production.

It was around this time that Münch, who was in dire financial condition, attracted the attention of American publisher and Cycle magazine founder Floyd Clymer, who partnered with Münch to create Clymer-Munch. Thanks to Clymer’s cash infusion, in 1967 Munch moved to new, larger premises and the Mammut was called the Munch 4TT.

Clymer arranged for U.S. distribution of the Munch, calling it the Clymer-Munch Mammoth IV and offering it starting in 1967 for the then astonishing price of $4,000. At the same time Clymer, whose real ambition was to revive Indian motorcycles, had Münch build a “new” Indian Scout using a 750cc Scout sidevalve engine benefiting from an electric starter and improved cycle parts. One Indian-Munch was built (it still survives) and displayed at the 1968 Los Angeles motorcycle show.

In early 1969 the European market 4TT became the 4TTS, and not long after it gained larger 41.3mm Rickman front forks and a new handmade aluminum gas tank (replacing fiberglass) that could be sized to customer requirement. By 1970 Clymer’s health was failing, and he sold his interest in Munch to millionaire Arthur Bell, who was looking for a suitable business opportunity for his son George. Bell commissioned a new factory in Altenstadt, near Frankfurt, and acquired URS, Helmuth Fath’s world-championship winning sidecar racing team. Rider Horst Owesle went on to win the 1971 sidecar world championship with a Münch-powered URS outfit.

Münch continued development, producing the 115 horsepower Sport-Münch and the 125 horsepower “Daytona Bomb,” which was aimed at beating Mike Hailwood’s 1965 one-hour speed record of 145mph, set on an MV Agusta. At Daytona, the Münch was averaging 178mph, but no rear tire would last more than four laps!

However, when George Bell suddenly pulled out and returned to the U.S. in 1971, Münch was forced into bankruptcy. He found a new business partner in the packaging manufacturer Hassia, yet just when things seemed to be going well again Hassia pulled out at the end of 1973, leaving Münch to declare bankruptcy yet again. The company’s assets, including the Münch name, were bought by entrepreneur Heinz Henke. Henke went on to produce a number of Henke-Münch motorcycles, but they shared little with the Münch 4TTS except the NSU engine.

Münch continued developing his bike under the Horex GmbH banner (he had purchased the rights to the Horex name in the late 1950s), including a 1,400cc turbocharged version of the fuel-injected TTS-E producing more than 140 horsepower, the 160 horsepower supercharged 1,800cc Horex Titan 1800 and a liquid-cooled 2,000cc Titan 2000 with a 4-speed plus reverse transmission.

Unfortunately, Friedl Münch suffered a massive stroke in 1991, and while he eventually recovered, production of his NSU-powered Münch motorcycles effectively ended.

Dale Keesecker’s Clymer-Munch IV

Almost 10 years ago, well-known motorcycle collector Dale Keesecker found a one-owner 1968 Clymer-Munch IV in the southwestern U.S. with just 4,500 miles on it. As it turned out, it was the first true Clymer-Munch, a claim that needs a little explaining to make clear.

When Clymer took financial control of Münch’s enterprise in 1967, he changed the company name to Clymer-Munch. Acknowledged Münch expert Mike Kron in Germany provides replacement parts and makes reproduction Münch Mammuts. Kron calls the 1966-1967 bikes up through frame number TT 014 Series 1 machines. Upon taking financial control, Clymer ordered all machines be built badged as Clymer-Munch, and for export only. Kron calls these the Series 2 machines, which began with frame number TT 015.

That’s the number on the swingarm of Keesecker’s bike, making it the first Clymer-Munch. Period ads had no umlaut over the “u” — in “Munch,” nor did the badge on the gas tank. Oddly, the speedometer, tachometer, temperature and oil pressure gauges have “Clymer-Münch” (with an umlaut) on their faces and the bike’s build plate identifies it as a “Clymer-Muench-Mammut.” And yes, the plate spells it “Muench,” with an “e.”

“I actually purchased it from the original owner,” Keesecker says of his bike. “He ordered it and brought it over direct from Germany. It had been stored in the open for a number of years, but because of the dry climate it wasn’t horribly bad.” Keesecker continues the story: “A number of parts were missing, and some were incorrect. I’m a perfectionist, so we did a total restoration. We tore the engine apart, and rebuilt it from top to bottom. We were really glad we took it apart. One of the roller bearings in one of the cases was cocked — eventually that would have created a major problem.” Aside from that, the engine showed limited wear, requiring only cylinder honing, new piston rings and new valve guide seals.

So how do you get parts for something as rare as a Münch? “I was at one of the motorcycle auctions,” Keesecker says, “and there was a business card lying on the floor. I stooped down to pick it up — it was the business card of Mike Kron. It just seemed like fate was putting it there.”

Kron would be instrumental in the bike’s restoration. “Everything that was missing or was incorrect on it, he was able to supply,” Keesecker says. “There were some castings that were gone but Mike had them. They were rough castings and we had to machine them down to fit, but that wasn’t real difficult.”

The two most challenging parts of the restoration were the fiberglass gas tank (later bikes had aluminum tanks) and the front brake hub, Keesecker says. The gas tank had originally been shaped with a separate compartment at the rear to hold the battery, with a lid over it, but the compartment had been fiberglassed over.

“When I talked to Mike Kron about it, he said ‘you absolutely have to put it back original,'” Keesecker recalls. “We could see where the original lid was, so we rebuilt it just like it was. That was quite an effort.”

Dealing with the Elektron front brake drum was also a challenge. First, Keesecker polished it and re-laced it to the rim with stainless spokes; but in a few months the surface had oxidized. Next, Keesecker tried a clear powder coat, but within a year it had started to oxidize under the clear coat. “So we de-spoked it and took it all down again, and this time we used a Hammertone paint on it, like the engine has, and it’s been fine. It was just so frustrating to have to do it three times,” Keesecker says.

Rare as Keesecker’s bike may be, he’s not averse to firing it up for a ride. “In its day, it was the biggest, fastest motorcycle there was,” Keesecker says. “But it’s incredible. You don’t have to get going very fast, 8-10mph, and you would never know it’s as big as it is. It’s really fun to ride. It’s so smooth, and once you get going down the road it handles nice.”

As to Münch’s famous racing drum brakes, “They’re not like brakes today,” Keesecker says, “but for me, they’re above average for their time period. And compared to my Vincents, it’s much better. Bikes back then would go faster than the brakes could stop them — compared to today when you can lock the wheel up if you want to.”

Keesecker also likes that his Münch is essentially unique. “Kron told me that even within the same series, there’s no two that are alike,” Keesecker says, adding, “a lot of people look at it at shows … some people think it’s so ugly, other people think it’s really a work of art.”

And that’s the charm of Friedl Münch’s creation. Outrageous in its day, it anticipated the direction of motorcycle development and stands as a lasting tribute to its designer and builder. Rarely is it possible to channel so intimately the dreams and passions of a visionary innovator as it is through the Münch Mammut. MC

To see more from Robert Smith, read Building a Münch From Scratch.