Open Saturday 23rd - Monday 24th October from 9.00 until dark. MIni, MX and Mini track in good condition, MX freshly groomed. Short and Middle length Trail will be open from 1.00 Saturday through the long weekend. Long loop closed. The Trail loops still have some wet areas so not recommended for beginners. If anyone is wanting to camp the night you are able to do this for free but you must be self contained (no water available, long drop toilet) . Just mention this when you sign in and pay for each day's riding.


The Air Scoop

Before Water Cooling

maddix park mx


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.

The top photo shows 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."

This article is part of Motocross Action Mag's series of Gyro Gearloose Inventions of the Day.


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