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December 17, 2013
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Do you remember Gyro Gearloose? He was an anthropomorphic chicken created by the Walt Disney Company who appeared in the Scrooge McDuck comic-book series. Gyro was the town of Duckburg’s most famous inventor. Because his inventions were rarely successful, the name Gyro Gearloose has become synonymous with any inventor with a crazy or crackpot idea. Motocross has had more than its fair share of Gyro Gearlooses?some amazingly successful, rich and lauded for their ideas, while others were derided, laughed at and forgotten for ideas that were just as good. Sadly, some of the most creative motocross inventions never made it to the bikes of a sport dedicated to innovation. MXA presents the latest installment in its series of weird and wacky inventions.


On the dawn of water-cooling, riders were looking for ways to control heat build-up in their air-cooled cylinders. The most successful idea was the DG Pro-Flow air scoop. It was a simple air scoop that attached under the gas tank and down over the fins of an air-cooled cylinder. At speed it increased air velocity through the fins by virtue of the Bernoulli Effect. The inventor was Jody Weisel.

Here is the Pro-Flow scoop mounted to an air-cooled 1980 Honda CR125. It may be hard to imagine, but 33 years ago all bikes were air-cooled. Eventually water-cooling eliminated the need for air scoops, although 500cc bikes stayed water-cooled for much longer than 125 or 250 two-strokes.

Although this bike says Derbi on it, it is actually a modified Suzuki RM250 with both a Pro-Flow scoop on the side of the engine and an air scoop front number plate.

Honda and Yamaha both decided that the Pro-Flow scoop was a good enough idea to copy. This is the production air scoop on the 1984 Honda CR500.

The 1987 Yamaha YZ490 came off the showroom with a black plastic air scoop. We asked Jody if Honda and Yamaha paid him royalties for using his design. He just laughed and said, “The air scoop was just a last-ditch effort to cool bikes that were rapidly getting more powerful and generating more heat than the finning could control. As with most ideas, I wanted to do something for my own race bike and was happy that other people could use it also. Neither Honda nor Yamaha were going to stick with air-cooling for very long, so I took pride in the fact that they liked my idea.”


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