For my 2014S, my notice for 2020 premiums (Geico) was nearly a 2x increase over 2019 --- with no obvious cause (no tickets, no accidents, albeit I'm a year older). I phoned a rep, who attributed the increase to changes in CA law that affected liability. When I asked which laws (so that I could send letters to my CA assembly member and senator), the only specific one the rep could offer was the law pertaining to texting while driving --- which seemed a bit of a reach to apply to motorcycles.
The note above regarding a minimum policy cost is something I found to be true at Geico, and I used the web quotes to test combinations of insurance types and deductibles to just get past that minimum level. For 2020, that Geico minimum appears to have jumped to >~$105 per 12 months, up from 2019's $75 though I might not have sampled the minimum set.