Here is a pic of the bike I worked on yesterday, it is a shiny nice looking bike 1937 UL
Check out the oil pump, This bike has been modified for skirt oilers. The extra oil line goes up to the cylinders and oils the skirts of the pistons. Some guy sells an instruction booklet on how to do this modification, his instructions are pretty good, but the section on machining the feed pump is incomplete, be careful if you ever do this mod by your self. The reason I was working on this bike yesterday, was because it was smoking out of the front cylinder. The service manual tells you not to use oil rings on the front cylinder on Us and Es. With the extra skirt oilers, there was some oil blowing past the two compresssion rings and into the combustion chamber on the front cylinder. So we pulled the cylinder put new rings in it and fixed the problem.