Nice collection you have there. I understand your struggle.
You will ,if you keep collecting , get to the point when you can't keep them all ridden. That's when maintenance issues come into play, mainly fuel related like sour gas kind of stuff. Gotta love doing carbs, if not, no worries , you'll get good at it.
Insurance probably won't be a big deal. My progressive insurance allows me 7 bikes on each contract, comes in at around $250 for both contracts. The first reg in NY is the more expensive one because you pay for title transfer ($50 plus reg and plate), after that ,it's a yearly lower reg renewal cost on each bike ($20) when you have title. Housing them safely in a decent environment and keeping up with the polishing and wax . It can be some work. Did I say nice collection?
