The cafe racer is a motorcycle that has been modified for speed and good handling rather than comfort. Cafe racers’ bodywork and control layout typically mimicked the style of contemporary Grand Prix roadracers, featuring an elongated fuel tank and small, rearward mounted, humped seat.
A signature trait were low, narrow handlebars that allowed the rider to “tuck in” to reduce wind resistance and offered better control when in that posture. The ergonomics resulting from low bars and the rearward seat often required rear-set footrests and foot controls, again typical of racing motorcycles of the era. Distinctive half or full race-style fairings were sometimes mounted to the forks or frame.
The bikes had a raw, utilitarian and stripped-down appearance while the engines were tuned for maximum speed. These motorcycles were lean, light and handled road surfaces well. 
1967 Bultaco Metralla MKII
The Metralla used the same two-stroke engine as used in the rest of the Bultaco line, this one punched up to 250cc. Doesn’t seem like much, but consider that the entire motorcycle weighed just 250 pounds, and the engine put out a screaming 32hp. A lot of imported cars from that era didn’t put out 32hp. In the day, 100 MPH was the gold standard for any production motorcycle, and the Metralla could get there. For a time, the Bultaco Metralla was the fastest two-stroke street bike in the world.
The Metralla’s oil mixing system is rather unique. Some bikes require a mixing cup when refueling. Others use an oil-injection system to meter oil and fuel as it’s used. Instead, the Metralla has an oil mix tank with a plunger. When refueling, give the plunger a few pumps, and the oil is precisely measured into the fuel tank.
Bultaco would continue building the Mk2 until 1975, when it was replaced by an updated model. In total, approximately 5,000 Metrallas found owners, at an original price of around $600. 
Bultaco was a Spanish manufacturer of two-stroke motorcycles from 1958 to 1983. Built in Barcelona, Bultaco motorcycles were exported throughout the world, but their largest market ultimately became the USA, allowing aspiring racers to purchase legitimately competitive motorcycles right out of the box.
MotoGP star, Sete Gibernau is the grandson of the founder of Bultaco, Paco Bultó. Legend has it that Mr. Bultó asked to be buried “with his Bultaco t-shirt and his moustache properly waxed”. 
1965 Ducati Mark3 Diana Super Sport
This machine first appeared in 1962 in Europe where it was named the ‘Mach 1′. It was derived from the production 250s but was considerably tuned and had 5 gears instead of the 4 of its predecessors. Several European magazines tested it and were able to exceed 100mph, making it by far the fastest production 250 on the market.
It was later introduced to the American market where, under the name of Diana Mark 3 Super Sport, it proved again to be the fastest 250 street bike in the world that year. In a carefully monitored Cycle World track test, the Mark 3 did a standing 1/4 mile in 16.5 seconds with a final speed of 79.5 mph. Its top speed was 104 mph. Even a TD-1 Yamaha racer, tested by Cycle World that same year, was unable to match the Ducati’s top speed and no other comparably sized registrable production bike that year could compete with its performance. 
1975 Harley Davidson Aermacchi RR250
If the Grand Prix road-racing record books came with footnotes, you’d see a reference to this Italian-built motorcycle next to the only GP titles ever credited to Harley-Davidson.
Back in the 1970s, Harley-Davidson actually was a force in international road racing, winning the 250cc class three years in a row.
How did a company known for big, slow-revving, four-stroke V-twins rack up such an impressive streak in a form of competition dominated by small, hard-running two-strokes?
In a word, Aermacchi.
Aermacchi’s trademark 250cc four-stroke singles, with one horizontal cylinder sticking straight forward, formed the basis of the Harley Sprint line of 250s and 350s.
Aermacchi officials, who in the Italian tradition believed that race performance was integral to success, continued to contest the Grands Prix using two-strokes under their own company name. Then, in 1973, the same machines were rebadged as Harley-Davidsons. A year later, factory rider Walter Villa began a string of three 250cc championships.
This water-cooled bike pumped out 58 horsepower at 12,000 rpm.
As a race machine, the RR250 was built in extremely limited numbers, which makes any surviving examples, like this 1975 model, owned by Benjy Steele of Huntington, West Virginia, pretty hard to find. But this particular RR250, now on display in the Motorcycle Hall of Fame Museum at AMA headquarters in Pickerington, Ohio, is even rarer: It’s never been started since it left the factory.
1975 Parilla 250 GS
The GS is not a works bike, but a production factory race bike. It came equipped to ride on the street and on the track. All a new owner had to do was to remove any parts deemed unnecessary and go racing almost immediately – an instant race bike right out of the box.
Giovanni Parrilla started work as a diesel injection pump repairman, but always had a passion for motorcycles. One day, given the current Italian poor showing at a world motorcycle competition, he blurted out that he could build a better race bike than the other Italian factories. It sounded a monstrous boast to the others in the group and they quickly bet him that he could not.
Giovanni, early in 1946, along with most other racing fans were in awe of the achievements of the Norton Manx; so he bought one. He took it apart, measured and studied it, then, when it was reassembled, he sold it and began his work in earnest.
Mere months later, his first offering won a local race. A man approached him expecting to buy the bike right there. Giovanni declined the sale, yet promised the next one to this interested buyer. Many years later during the late 50′s and 60′s, production of the high-cam 175 and larger Parilla Gran Sports, the Norton classical colors and graphics were used on Parilla competition models, in honor of Norton’s contribution to the design success of Moto Parilla. 
1964 Honda RC164 250cc
This machine is a pristine 1964 four cylinder RC164-1 Honda 250 Grand Prix racer. The bike was ridden by Jim Redman for most of the 1964 World Championship season before he switched to the new six-cylinder version for the final two races. Redman finished second to the Yamaha 250 two-stroke of Phil Read in one of the most hotly contested championships in history. Redman won the Isle of Man TT and the Dutch TT at Assen on the machine, on the latter occasion becoming the first man ever to win three Grand Prix classes in the same day.
Built for and run by the works team, with only occasional loans to selected privateers, these hand-crafted masterpieces are extremely rare. Only three complete four-cylinder machines of this particular type were made by Honda, and this one still has matching frame and engine numbers: ‘RC164-1’. It is believed to be the only original example of its kind still in existence.