Turbulence management

When I first took my KLR on the highway, one thing I did not like at all was the wind noise. There was a continuous roaring and snapping like the end of a flag or sail snapping in the wind - very loud and very uncomfortable.

I quickly determined it was not my helmet (HJC Symax) that was the problem, because when I stood up on the pegs, there was only a quiet, smooth flow of air; no turbulence at all.

It got so bad on my first long trip that I tried removing the windshield altogether and stowing in my pack. That was a little better, but resulted in too much wind blast on my chest. And it didn't look very nice, either.

It was time for a few experiments. I had often read that the key to reducing turbulence was to get some air flowing behind the shield too, as is done on many big road bikes. My first attempt at this did not work: I duct taped some dryer vent hoses from out in front of the fairing to the back of the 'shield.
Result: No effect.

Next I tried moving the windshield out forward of the fairing, thinking the resulting gap would dump some air in and reduce turbulence.
Result: No effect.

At this point I saw an ad for Saeng Stealth edging , and this seemed like it might be the answer to my problems. I ordered it, and found I had to buy a minimum of three feet. All in all, the price came to $75 Canadian by the time it got here, what with exchange, duty and taxes.
Result: No effect.

Thinking that the problem might be no place for air to flow with edging all around, I tried edging only along the top. This way, perhaps the air would flow off to the sides, reducing turbulence over the top.
Result: This was the best solution so far, but it still wasn't very good - the classic "tallest midget" situation.

At this point I called up a local dealer, and they had the tall windshield in stock.
Result: No beneficial effect, with or without edging. However, by moving my hand up and down in the airstream, and juding by pressure on my helmet, I estimated that the turbulence had simply moved up about 4 inches higher on my helmet (the factory tall windshield is about 4 inches taller).

Then came a piece of luck. We were cleaning out our offices some time later, and one of the things I saw was an old 3-ring binder with a stiff plastic cover. I looked and that plastic, and suddenly thought I might use it to try making a LOWER windshield to drop the turbulence lower, away from my ears. It was easy to cut the plastic with scissors, using the stock windshield as a pattern.

Starting with a height a little lower than stock, I road tested the noise levels, gradually scissoring it down by about 1 cm each time. The lower it got, the better (i.e. quieter) it sounded. I began to be able to hear the engine at 110 km/h, something that only happened before if I had a tailwind!
Result: I finally settled on a height of 3 inches. Turbulence was practically eliminated, and I could just feel the wind pushing at the tops of my shoulders, so that felt like the right height.

This little silver plastic "bikini" windshield looked so saucy I was tempted to keep it as is. But the width wasn't quite right - that old binder was just a little too narrow to cover the full width of the fairing. So I went to a local industrial plastics shop hoping to find a bigger piece of stiff plastic.

Cool place, all kinds of neat gadgets and glues. I explained the intended use to the counterman, who was very knowledgeable and helpful - nice to find a guy who really knows his shop. He recommended 3 mm Lexan. It was relatively easy to cut to size by repeatedly scoring with a drywall knife. For the top rounded corners, I scratched the curve from a shot glass on the surface, then removed the excess with a knife and an ordinary metal file. Lots of messy shavings, but easy to do.

Result: Now I have much a less fatiguing ride, and am able to enjoy the thump of the engine rather than a hurricane beside my ears. I also have lots of leftover Lexan, because you have to buy a minimum 2 foot by 2 foot sheet, and I only needed a 4 x 14 INCH strip. Oh well, bound to come in handy for something.