Heck Stig, a couple years ago I looked into it since I wound up buying an S200 down there.
"Mopeds" don't require insurance, but the usual rules apply to call something a moped. You can do the "Post a Bond" thing if you want. Not sure how the numbers roll on that.
WA state other hand, does not require insurance on motorcycles at all.
As a result decent coverage is cheap, but you do have to keep an eye on what is & isn't in your policy since they'll "forget" stuff like PiP even if ya ask 'em.