Im specifically referring to motorcycle engines, but for arguments sake a car engine wouldn't matter either
Say 100Nm was measured at the wheel using a rolling dyno, then based on the reduction ratios(say 5) from wheel to sprocket to gearbox to the clutch, would the torque produced at the crankshaft be less? 100/5 = 20Nm
Assuming no losses, the power produced at the engine would be the same at the wheel but since there are multiple gear ratios, the torque is increased whilst the angular speed has reduced. So if the crankshaft was turning at 10000 rpm... with an overall gear ratio of 5. The wheels are turning at 2000rpm?