As Chainsaw from a used water pump 

The saw axle sits off the water pump
for those who want to try to find a former dynamo ai pump, at least two used dynamos, from the two used dinaos we take the cover near the fan, that's for the axle holder, for the rotor we take it off, just take the axles off ... for The pully can be used as a 2in pulley, the diameter of the axle hole is 12mm, for the rubber pen, you can use a used washing machine penbell size M.