Exactly where you need to find these things
<vehicle name="vehicleMinibike"> <property name="cameraDistance" value="3, 4.5"/> <property name="cameraTurnRate" value=".2, .35"/> <property name="upAngleMax" value="70"/> <property name="upForce" value="1"/> <property name="steerRate" value="130"/> <property name="steerCenteringRate" value="90"/> <property name="tiltAngleMax" value="20"/> <property name="tiltThreshold" value="3"/> <property name="tiltDampening" value=".22"/> <property name="tiltDampenThreshold" value="8"/> <property name="tiltUpForce" value="5"/> <property name="motorTorque" value="400, 200"/> <property name="turboScale" value="1.4, 1"/> <property name="velocityMax" value="7, 4"/> <property name="brakeTorque" value="3000"/> <property name="hopForce" value="1.5, .2"/> <property name="unstickForce" value="1"/> <property name="waterDrag_y_velScale_velMaxScale" value="1.5, .9, .15"/> <property name="wheelPtlScale" value=".6"/>
First value in motorTorque is forward direction, second one is backward direction
Motorcycle and 4X4 motor torques for comparison
<property name="motorTorque" value="1400, 500"/> <property name="motorTorque" value="1800, 900"/>
Code to put in a modlet so you can change them
<set xpath="//vehicle[@name='vehicleMinibike']/property[@name='motorTorque']/@value">X,Y</set>
Change X,Y to the values you want.