Scrambler & Dirt Bikes

If pre-WW2 motorcycles were designed as a “jack of all trades” machine, the post war era gave birth to more specialized bikes for on and off-road use. Many were configured to serve as race machines in off-road competitions, such as closed course Moto Cross races popularized in Europe, requiring the bike to be ridden over rugged terrain that tested the machine’s suspension. Long distance Enduro races and precision off-road Trials competition pitted bike and rider to negotiate challenging obstacles such as rocky slopes, rivers, and hill climbs. Traction and handling was key to success in Trials while the wide-open deserts of Southwestern US bred high speed Desert Racers and Scramblers which required their own specifications for durability and speed.

European manufacturers answered the call by offering small and mid-displacement off road bikes, designed specifically for competition riding. Excess weight was trimmed by omitting lightning, heavy mufflers, and adding light weight alloy fenders and high-rise exhaust pipes that would increase ground clearance. Telescoping front suspension and swing arm rears with shock absorbers became standard fare. Early dirt bikes typically had single cylinder 4 stroke engines, tuned to deliver higher torque for Trials and Enduro events while Moto Cross and Desert racers favored engines with higher top speeds. Tires with knobby treads commonly found on military models were adapted to suit mud and sand conditions offering superior traction.

In the 1960’s two factors changed the direction of off-road motorcycling dramatically: the use of lighter weight 2 cycle engines and the influx of affordable Japanese made dirt bikes.

Since Motocross was considered primarily a European grown sport, builders such as Sweden’s Husqvarna, Spain’s Bultaco, England’s Greeves, Germany’s DKW and Czech CZ began incorporating the lighter weight, more powerful, and mechanically simpler 2 stroke engines in their dirt racers, with a great deal of success. By the mid 60’s, 4 stroke bikes from BSA, Triumph, Ducati and Parilla no longer dominated on the track.

In reconstruction efforts and the development of motorized bicycles, post war Japan looked to the US as a focus for building new business. Soichiro Honda made significant inroads through clever marketing and designed a family friendly Honda Cub 50 motorbike with a semi-automatic transmission. Using a stamped steel frame with 4 stroke reliability, the same basic design spawned several off-road capable versions with separate high/low range gearing options. Unlike Honda who had always focused on his own engine development, several Japanese builders diversified from other industries such as musical instrument manufacturing, aviation, and textile equipment, copying European bike designs and engines that could be adapted to domestic and export markets. Light weight and inexpensive, most Japanese street bikes were also offered as dual purpose “Scrambler” models with mild off-road capabilities. To compete against the European marques in an effort to gain recognition on the worldwide competition stage, Honda developed its own purpose built two stroke Moto Cross machines, the Honda Elsinore, named after the popular California motocross track. Suspension developed dramatically and soon bikes were offered with dual and single shock absorbers with close to 12” of suspension travel.

Documentary California film maker Bruce Brown, fresh from his success with surfer lifestyle movie “Endless Summer”, released “On Any Sunday” in 1971 just as motorcycle use was transitioning from the hard-edged perception of biker gangs to the more mainstream and more socially acceptable of sporting and recreational bike use. His images of popular Hollywood movie star Steve McQueen competing in desert races and riding Husqvarna 250s on the beaches and sand dunes with fellow racers and enthusiasts, Malcolm Smith and Mert Lawwill created a boom in off road riding that continues today.

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+ 1963 Honda C105T Trail 55

The Honda Super Cub is the world’s most produced motor vehicle in history, with over 100 million manufactured by 2017. The Honda Trail 55 is a variant of the Super Cub, intended for hunters, campers and light trail riding. Also known and the C105T or Trail Cub, it was available from 1962 to 1964 before being replaced by the CT200 Trail 90 series.

The machine on display here is an early unrestored example that has covered fewer than 1,400 miles. These inexpensive machines generally led a hard life and this one shows typical wear and tear expected from off-road use. The step-through frame design incorporates a high-mounted air filter; the gas tank is underneath the folding seat. The front fender, rear carrier and ‘buddy seat’ are typical period extras.

One unusual feature is the dual rear drive sprockets, one over-laying the other. This was to provide a set of lower gear ratios for off-road riding. To switch ratios, it was necessary to detach the drive chain, install an extra length of chain and re-position the large sprocket before replacing the chain. The Honda Super Cub and its variants debuted in 1958, just 10 years after the establishment of the Honda Motor Company, Ltd. First imported to the United States in 1959, the American Honda Company had ambitious plans to develop an entirely new customer base for their motorcycles, targeting new riders with cheap, convenient and reliable motorcycles. In 1962 they launched their famous advertising campaign “You Meet the Nicest People of a Honda”, devised by Gray Advertising in Los Angeles. Considered one of the most effective campaigns ever, it completely changed the image of motorcycles and riders, who were previous thought of as the greasy biker gangs depicted in movies such as The Wild One.

Specifications:

54cc single-cylinder, air-cooled OHV motor
3-speed transmission with high/low ratios and automatic clutch
120mpg; 45mph top speed

+ 1966 Ducati 250 Scrambler

The Ducati 250 Scrambler on display here is in completely original, unrestored condition – right down to the factory-fitted Pirelli tires, having covered fewer than 700 miles from new. These bikes generally led a very hard life in the hands of young riders; finding one as well-preserved as this is extremely rare.

Unusual features to note include the right-hand side ‘heel and toe’ gear-shift lever and a kick-starter mounted on the left. The low-level exhaust system has no muffler, although one was offered as a dealer accessory, as was an engine protection plate to prevent damage during off-road excursions. A distinctive feature of these single-cylinder Ducati motors is the overhead camshaft, driven by a vertical shaft via bevel gears on the right-hand side of the motor.

In the early 1960s, Ducati’s highly influential distributor, Berliner Motor Corp. recognized the huge potential for dual-purpose motorcycles capable of being used on or off-road and persuaded the factory to design one. Introduced in 1962, the 250cc Scrambler was an immediate sales success. Although it was not a serious contender in scrambles or dirt-track racing, it reflected the popular sporting image of the period. The 250cc model was followed by 350cc and 450cc until Ducati ceased production in 1974.

The Scrambler series was derived from the Fabio Taglioni-designed 250cc Ducati Diana roadster, released in 1961. By the following year the Diana Mark III was the fastest 250cc machine available, with its top speed of 104mph beating even Yamaha’s purpose-built TD1 race bike. As a result, Ducati started to gain a reputation for high-performance lightweight motorcycles and led directly to the highly acclaimed 750cc twin-cylinder 750GT model in 1972. The 750GT featured a unique 90-degree “L-Twin” engine format that continues to be used today.

In 2015 Ducati re-launched the Scrambler concept as a range of twin-cylinder machine, aimed at the retro / lifestyle market, available in a range of capacities from 400cc to 1,100cc.

Specifications:

249cc single-cylinder air-cooled OHC motor, 5-speed transmission
65mpg; 78mph top speed

+ 1973 Husqvarna 450 Desert Master

Purpose built off-road bikes grew in popularity in the late 60’s as different types of competitions such as Moto Cross, Enduro, Trials, and Scrambles were held in the US and Europe. Uniquely American, Desert Races in the wide-open Southwest required long travel suspensions and a tractable engine to survive in sand and rough terrain at high speeds. Based upon the 400cc MX bike, the Husqvarna Desert Master 450 arrived in 1973 with the hopes of an improving sales for US importer Edison Dye. To promote the new model, successful California desert racer Malcolm Smith was hired to compete on heavily modified Husqvarna’s that were cosmetically similar to the Desert Master but had unique features added to Smith’s specifications. Unfortunately, the high price and and marginal performance were to make the Desert Master a sales flop.

Swedish manufacturer Husqvarna has a reputation for quality products ranging from sewing machines to chain saws and as dirt bike riding popularized in Europe gained a foothold in the US, “Husky” Motocross machines like the CR and WR models were common at the start of most off road events. Unlike British bikes, the Swedes used 2 cycle engines to power their bikes and were good handling light weight bikes with refined suspension. Fuel tanks and fenders made from light alloys and tuned expansion chamber exhausts helped performance.

When Malcom Smith and Steve McQueen took to the big screen in Bruce Brown’s iconic film “On Any Sunday”, Husqvarna’s were prominently featured in desert and sand dune riding scenes, offering plenty of free advertising for the brand. And while the 450 Desert Master did not live up to its name as the dominant large displacement off road machine as intended, it set the stage for future open class Husqvarna motorcycles that successfully competed around the globe.

Specifications:

Engine displacement: 456cc
Horsepower: 45hp
Weight: 240 lbs
Suspension travel: 7” front, 6” rear

+ 1976 Bultaco Sherpa T 350 Trials Bike

This Spanish off-road motorcycle was purpose built for competition in Observed Trials initiating the transition from heavy British 4 cycle powered Trials bikes to lightweight 2 cycle machines from the European continent. Observed Trials requires the rider to negotiate challenging obstacles, sometimes at very slow speeds, while keeping their feet on the footpegs and maintaining their balance. 60lbs lighter than 500cc 4 strokes but with similar power, The Sherpa T evolved from a mid-60’s collaboration of Irish Trials Champion Sammy Miller with Bultaco, primarily known for small displacement street and trail bikes. Miller abandoned British manufacturer Ariel to be the first to compete on the new Spanish bike and found immediate success.

Bultaco was established in 1959 after a former Montessa director, Francesc “Paco” Bulto, left the Montessa company over a disagreement to continue providing factory support for motorsport. Gaining success with Miller in the UK in the late 60’s, the Barcelona based factory recruited star UK riders Martin Lampkin and Malcom Rathnell. The result was a first ever World Trials Championship, with victories continuing throughout the 1970s. The Sherpa T increased in displacement from 250 to 326cc. Soon trials riders everywhere switched to Bultaco and other Spanish Trials bikes from Ossa and Montessa.

The 350 Sherpa T offered only 21 horsepower but had a heavy flywheel for low-speed maneuvers along with a 6-speed gearbox. Betor hydraulic forks and shocks featuring 7 inches of travel would allow the bike to be ridden over large rocks and logs while tires were kept at lower pressures to add grip over slippery surfaces. Bultaco’s success was to be short lived as political and economic forces were to drive the company out of business for good in 1983.

Specifications

Engine displacement: 326cc
Horsepower: 21 hp
Weight: 176 lbs

+ 1979 Honda CR 250 Elsinore

The Honda CR250 Elsinore was the natural progression both for Honda as a company as well as for the budding Moto-Cross rider who had been raised riding Honda motorcycles. 1973 marked the year that Honda began marketing and selling 2 cycle engine purpose-built Moto-cross bikes that would compete wheel to wheel with bikes from Europe. And the Honda was good, right out of the crate. Fast forward 5 years, and the conservatively styled and somewhat dated CR got an extreme makeover, painted completely fire engine red with an all new single down tube frame, Euro style drive train with a right-side chain and sprocket and reed valve induction. Suspension travel grew to an astronomic 11” front and rear. Notably 1979 was the first year that Honda moved production of the Elsinore to its Marysville, OH plant in the USA.

If a young racer had moved up from his first Honda Trail 50 and began competing in Moto-Cross events on smaller 125 Honda Elsinore bikes, he knew that bikes from Yamaha, Suzuki, and Kawasaki had more power and better suspension by the time 1976 rolled around. But Honda’s “Red Rocket” CR250R changed all that in 1978 with a much-improved bike in the 250 class which carried over to the 1979 model year. Lightweight aluminum alloy components such as rims and wheel hubs and leading axle front forks added to the handling. Much was borrowed from the successful RC250 Works factory race team machines that competed in world championship outdoor Moto-Cross racing and even the kick start lever and gear change pedal were crafted from aluminum to save weight. Liberal use of Magnesium in the motor had the engine weighing in at a mere 56lbs.

While the ‘79 did not win any world or national Moto-cross championships, the bike was a viable competitor in the hands of skilled rider who could use all the power and suspension the bike had to offer.

Specifications:

Engine displacement: 248cc
Horsepower: 29 hp
Weight: 212lbs
Suspension Travel: 11” front, 11” rear

+ 1982 Honda CR 480R

Open class Moto-Cross race bikes have never been for the weak of heart and riding the ‘82 CR 480R was no different. While its smaller brethren in the 125 and 250cc Honda MX line up featured a liquid cooled 2 stroke engine, the 480 remained air cooled with a 4 speed transmission. Moto-Cross machines benefit from rapid development and were always updated from year to year to remain competitive. Honda was no different and between 1981 and 1982 displacement grew from 450cc to 472cc and benefitted from a revised Pro-Link single shock rear suspension. What was unconventional about the CR480 along with prior CR models was Honda’s use of a right-side chain drive and left side kick start. While common amongst European companies such as Husqvarna and Maico, riders switching from other Japanese brands were off put when it was required to start the bike with a left footed kick.

Once the bike was started, riders were rewarded with a very light and powerful bike with 51 horsepower on tap and had an impressive power to weight ratio. Several US racers such as Danny “Magoo” Chandler, Chuck Sun, and Steve Wise used this power to great advantage and dominated AMA Open Class racing against other open class machines from Kawasaki, Suzuki, and Yamaha. In its final year of production, CR 480Rs would get fully adjustable front Showa forks and a 5-speed gearbox.

Specifications: