Good evening,
I was reviewing this thread saw the "my dyno will out run your dyno" argument. I will go ahead and tell everyone that I am NOT an expert tuner of drag ATVs. I do review a large number of dyno pulls for a large private fleet's road tractors, they have to be dyno pulled before turn in to the leasing company.
So I do know a little about dyno's and their results. First that dyno's don't "read" horse power, that number is a figment of the operator and computers imagination. They only read torque which is twisting force on the drum only. Then you have to look at what size drum & how much weight of the drum & what is the calibration or lack of on the unit. If you have a dyno that is calibrated for 500 ft. lbs. with 1%. Then drop back to the atv range let's say 50 ft.lbs. just to make the math easy say 50 ft lbs. now we could be 10% off now.
Their is also the "weather station" & corrected h.p. when I see this on a dyno sheet it is highly suspect. The operator can move them where ever you want. That is where the amazing results of the mobile dyno guy comes from at bike shows. They pull your bike on their make a pull then screw with the carb correct the weather numbers & now you get 10% more horse power WOW! So in closing a dyno is just one tool for helping in racing & tuning. Because how many hours & fun at the track would be lost screwing with jetting & or timing. When you could go to a dyno & tune right their. This has got really long & looks like crap grammar, but oh well I am drunk.