"John Martin" wrote in message
oups.com...
So, Chris, just where does that extra torque come from?

The increased drag will cause the transmission to wear faster. But it
won't cause it to break. Nor would putting it in a semi, although the
clutch wouldn't hold up.

John Martin


You are basing your thinking that the motor is putting out its entire torque
curve in the bike at all times, which it is not. In order for it to move a
heavier machine more of the torque will be required from the motor at a more
consistent curve. Bike motors are built for HP not torque, although there is
still an inherent amount of torque there, that is not really called upon.

At the extreme, take the driveshaft from the motor and tranny and weld it to
a 20,000lb weight. Then you will see what the consistent full torque from
the motor will do to the tranny. Better yet take the original bike and have
it drag around a 1200lb trailer. Tranny should not last that long.

You are correct increased drag will kill the tranny faster. Drag means more
torque to overcome = more torque being passed through the tranny. In the
same regards weight will require the same. To overcome the weight more
torque will be needed. More torque being passed through = greater
deflection = failure.

Look down a couple of posts, seems like there was even an issue with the
tranny not holding up in a 385lb bike.