RADATORS
This is Donna's Trike when I first built it. As you can see, I mounted 2 Goldwing Radiators that get direct air flow. These two Radiators have worked perfectly in all conditions. I have recently made some changes to this Trike and now have the Radiators mounted just a couple inches off the floorboards with out the framework around them. They are much harder to see now and don't stand out like they did before but still work great. There are no doubt other ways and other types and sizes of Radiators to chose from, but whatever you chose to use, the key is not bigger higher valume Radiator. The Key is air flow. If they don't get enough air through them you just wind up with more hot water and a hot motor. These 2 Radiators hold the same valume of coolant as the stock full size Radiator, about 1 gal.
Well thats all there is to it. If you need any help or advice, I'm just an email away.
GOOD LUCK & HAPPY TRIKEING
GO SUBARU