How is RPM measured at an actual field test at an enduro or ranger stop? Do they stick a tach on it or just run the throttle to half? I've heard they just twist to half throtttle. About a month late on my response....(been busy I guess)... At the enduro and harescramble races that I attend, they have a book that lists all of the motorcycle brands and what the "half of max rpm" is listed. They preform the test by placing a vibration tachometer on either the motor or your rear fender and then twist the throttle until the tach tells them that they are at the right RPM level. Then another guy takes the db reading at that specific RPM. It's a crude test meaning that there is a lot of operator variablitly in the test. The person taking the test should be well trained and have some experience to preform the test correctly. Something as simple as standing in the wrong spot can throw off the db meter.