Fans are amazing. You can purchase some cheap ones as they are, and even cheaper if the parts are seperate(fan, wires, battery pack, switch, etc.) To solder one yourself. Not only do they keep you cool, but will also prevent fogging if angled twards your vidor. There are some anti fog sprays thag may be worth a shot. I dont know if this is possible, but adding some sort of ventilation or repositioning your helmet will also help a little