Currently in Cambodia and whilst touring around in a Tuk Tuk heading for  the temples I see a scooter in front of us towing a trailer. Nothing unusual for this part of the world. But then I see a trail of liquid from around the engine area hitting the ground ???   Thinks I, as of course these little scooters over here are air cooled. Nope, not this one. Old mate had a bottle of water mounted on the trailer behind him, a pump beside that powered somehow by 12 v which when the bike was running pumped water thru a hose and onto the cooling fins of the engine. Hey presto, water cooling !!!  This then just ran down onto the road leaving a tell tale water trail behind the bow which is what caught my eye. Unfortunately I wasn't quick enough to get a video as we rounded him up. 

Quite clever albeit archaic I thought.