If your motor is getting hot (to hot to touch) then it needs to be cooled, a muffin fan blowing air in past the brushes should do the trick, a higher air flow would be ideal if you were making long trips with it but a muffin fan isn't going to draw more then a few watts.
Tires are going to help,
Schwalbe Big Apple tires are a LRR tire and are pretty light weight for their size, they also have higher load ratings then a lot of narrow racing tires.