I use a bicycle air pump, it has a gauge on it.
It clips on the valve, no air loss when removed.
I will save the money that the Harley pump costs and put it towards some better shocks someday.
Damn!! I just went through this yesterday. riding 2 up with the OL and could feel it was getting a little bumpy. Thought... hummm.. shocks might need air added. Ran by the dealer, parts guy is like here ya go bud. I say how much, he's like umm, $52 bucks, I'm like PASS! Ridiculous price. It's like $25 for the pump and $25 for the HD logo! AND.... They still got me for $50 bucks. Wife liked a shirt while we were there.... Arrrrr! LOL!
HD is not the only one that makes those pumps. I use the one that comes with each set of Fox Float shocks on my snowmobiles.
The Fox air pump has all the features of the HD pump, available through any Arctic Cat or Yamaha snowmobile dealer for about $34 USD. Always someone upgrading thier shocks on a sled - could probably look in a sled parts section on e-bay or craigslist. There are two types available - one from 0 to 150 psi, and one from 0-300 psi.