Real information about modern motocross bikes is hard to come by. Most bike tests are filled with buzzwords and carefully crafted phrases that make any hard-nosed point fuzzy around the edges. That is a game that the MXA wrecking crew doesn’t like to play. We don’t believe that sugar-coating bike tests does anyone any favors—certainly not for the consumer who needs the best information possible to make the most of his hard-earned cash. And, surprisingly, many factory test engineers prefer tests that tell the truth—even if we criticize their handiwork. Why would factory engineers want MXA to castigate their products? Because they want their bike to improve, and sometimes it takes an outside evaluation to nudge the men upstairs to unleash the needed R&D dollars. In the process of testing motocross bikes, MXA takes months to form an opinion. We live with the bikes, fix the problem areas, struggle with the bugaboos, race them, sound test them, weigh them and dyno them. And so we have gathered here to talk about MXA’s dyno runs on the 2013 450cc motocross bikes.
ANALYSIS Not just numbers, but lots of numbers
bikes. We fill out test reports. We let our emotions run free. Then—and only then—do we consider the cold hard facts of the dyno. Why do we downplay the dyno’s influence? Because we’ve ridden bikes that were roaches on the race- track and jewels on the dyno. These are called “dyno queens.” We have also ridden bikes that could barely move the needle on the dyno chart but worked wonderfully on the track. We like to think that we can use the dyno to confirm what we felt on the racetrack, unless it doesn’t confirm it— in which case we go with our feelings. WHAT DO WE HAVE HERE? The following information is based on MXA’s dyno runs of the five major 450cc motocross bikes. We isolated the horsepower ratings at 6000 rpm, 8000 rpm and 10,000 rpm to get a graphic display of what the power looks like at three major points on the curve. Then we graphed peak horsepower, peak torque and, most important, we measured how wide the rpm range was where each bike topped 50 horsepower (as a measure of the breadth of the bike’s most usable powerband). Finally, below each chart is a quick analysis of what it all means. BASIC DYNO ETIQUETTE MXA breaks-in every bike at the track, and then takes it to the dyno. We test every bike on the same dyno and have used the same dyno for a decade. We try to control all the factors to ensure that we get the most accurate dyno runs possible…and we return to the exact same dyno when it comes time to test pipes, pistons, port jobs, ignitions or fuel. You cannot make comparisons from different dynos; you have to use the same one if you want valid numbers. As much time as we spend dynoing bikes, you would think that we would rely heavily on the results. We don’t. We still test the old- fashioned way. We race. We switch