The "liquid cooling" was provided to cool the exhaust ports so the guides and seats would stop falling out!
I does cool the heads approx. 30 deg, but does basically nothing, imo, for the exhaust heat, which they want to keep at 1100 degrees or so to meet emissions with the cats. the cooling system capacity is no where enough to actually cool the entire engine, only stop already overheated parts from disassembling.
The engines as they come from the factory are notoriously lean, right on the edge, resulting in engines that run far hotter than would be normal if they had an AFR correct for an air cooled engine.
My Twin Cam, carbed 01 ran at 200degrees oil temp, my 07 124 S&S runs at 190, no matter the day on the road. They both heat up stalled in traffic, but neither have ever gone over 230, still completely safe, even with non synthetic oil. I run Mobil Vtwin 20-50 fwiw.
Its another shortcut HD took to get by for another emissions year imo. They'll do anything to make you believe they are building a wonderful product, when the bottom line now is lining the pockets of the shareholders. If you give Honda $40K, you'd get the finest motorcycle made from the very best components it has to offer, without compromise or buying second class parts from 3rd world countries.
I will never buy another POS from them, my next bike will be Japanese. fwiw twinotter