Ivan Vegvary wrote:
... doesn't have the power that it used
to and it kind of 'sputters'. ...

This is the most significant symptom. Likely a dirty carb, especially
if it sat over the 6 winters with gas in the carb. These carbs are dirt
simple - tear it down & clean thoroughly, THEN see what it runs like &
worry about what else might be wrong, if anything.

Left side plug is sooty (black) compression is 72 p.s.i. Right side plug is
normal (light brown) but compression is only 40 p.s.i.
snip

"Sooty" is too rich, as you know. Why one side & not the other is
puzzling to me, but I've never worked a twin. But clean first, then
check again.

You can't do compression checks on these engines - it's meaningless.
Well, twins may be different, but I doubt it.

Clean the carb.

Bob