anybody know about the past liquid cooled knucklehead and shovelhead motors?

HD definitely marches to a different drummer, unfortunately that drummer is a one-armed caveman with a hard-on and that arm is busy at the moment. Call back in 50 years.

The Drake water cooled Harley engines were pretty successful race car engines for 15 years or so starting in the late 1930's.

But Dale Drake was no back yard tinkerer, he also designed the famous offenhauser race car engines.

Interestingly enough the 89 cubic inch V twin drakes often beat the 91 c.i. 4 cylinder Offys on dirt tracks.

You may not be aware that Harley spent $15 million developing & building a water cooled V 4 in the late 1970's.

http://big-diesel.blogspot.com/2007/09/nova-harley...

but market research indicated it might not sell very well so around 1981 they canceled it & concentrated on developing a vastly improved pushrod V twin which was finally released for sale to the general public in 1984.

This was probably the right decision because 3 years later when a suspiciously identical water cooled V4 rebadged as the Yamaha Vmax came out it got great magazine reviews but not many people actually bought one.

People shopping for Chevy Tahoe's & Cadilliac Escalades seldom buy Mazda miatas & like any successful company Harley caters to their specific market base.

its harely, they could have improved their bike 100s of times over the years and never did until just about 10 years ago, so if you bought a 1990's harley it is near the same technology as one from the 70s besides hydraulic lifters pretty much and belt drives on some of them.