Dyno Day.

[fnfalman]

Originally Posted by Ebbs15

so then how did they caculate the hp with out knowing the torque?!

That's why the dyno has the weighted drum that your bike's rear tire turns. That drum is weighted and calibrated. How fast it turns is calculated into horsepower. That's why it doesn't require your bike to have the RPM (aka attaching the clip to the sparkplug wire) to calculate for horsepower. However, it doesn't KNOW how fast your engine is turning, so if you were to want torque measurement then it needs to know your RPM via the spark plug connection thingie so that it can calculate backward from horsepower reading at the rotating weighted drum against your engine's RPM in order to calculate for your bike's torque.