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After explaining this to several bikers and co-workers, I'm beginning to think it isn't widely known, but I thought it was. I started doing it in 1967 when I was 17 years old with my Kawasaki 120 Bushwacker.

Before making performance improvements on cars, motorcycles, etc. I always do what I call an asphalt dyno base run. It may be called something else in your area, but it is not what is known as Butt Dyno, which is entirely subjective.

Pick a convenient, flat, stretch of road. At a specific point in the road, a stripe across the rode is best, but it can be a seam in the road, a crack in the road, a divet, etc. (Sign posts used as markers provide less reliable results.) Cross that point at a specific speed or engine RPM. Lets say 30 MPH or 3000RPM, whatever you want. Go to full throttle as you cross the stripe. At another stripe, further down the road, note your speed or engine RPM. If you run it both directions down the road, about 3 times and average the results, one gets a pretty good baseline for that vehicle, that is not sensitive to wind speed and direction. The roll on can be a variable, but after a few runs the mind and body learns and it stops being a factor. One just has to learn not to anticipate the stripe and wait till the front wheel crosses the stripe to roll on.

On the Scout I use 3rd gear, 30MPH and pick the end distance so I'm doing about 90MPH with no gear changes during the run to eliminate variables. I usually use RPM, but the Scout tachometer leaves a lot to be desired. Either way, this gives me an indication of performance over a wide range of engine speeds.

One can pick the roll on point and the exit point to highlight the range of engine speeds they are targeting for that vehicle.

Now, when I make a change in a vehicle, I can see if it actually did any good... for real. This method works for any changes, tire size, gearing, intake, exhaust, ECU tunes, and can also show how much a fairing, windshield, lowering a car, ground effects on a car, etc. is affecting your performance.

One note of warning, this method provides fairly repeatable results that may hurt your feelings. Your new noisey slip-ons may have done nothing for your asphalt dyno results. Gearing, Intakes and ECU tunes on the other hand will make significant improvements. I'm up a total of 11 MPH over stock on the Scout with Zippers, Bassini 2 into 1, and Fuel Moto tune.

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