I have a Vidhata 6/1 nicely mounted on a steel I beam roll around frame and have built it into a 2500 watt generator unit. Construction is just about finished except for a cooling system and that's where I'd like to get some input. I was originally going to use a tank/thermosiphon system but now I'm leaning towards a more compact, modern configuration.......a radiator. Now, I've only test run this engine so far and cooled it with a garden hose for water circulation, with the flow turned down to a trickle.....so I really don't know how much cooling is required.
I've seen at least one unit that used the radiator from a Honda Goldwing motorcycle that I thought was really good as the radiators are inexpensive and plentiful. Only thing is they're small, perhaps 11" x 9" and the one I saw had the radiator mounted low on the frame so he may have been using a pump (couldn't tell in the video). My setup would be up at the cylinder height and thermosiphon, but with the advantage of an electric fan.
The other option would be the radiator from a Honda civic. These too are plentiful and a new all aluminum double core can be had for around $60, again being equipped with a fan. These are much larger, in fact maybe a bit too large but it would definitely cool things.
I'd prefer the Goldwing unit, but not if the cooling is dicey. Are there any other radiators out there?