My FJ is £89 per year, "fully comprehensive" with legal services cover included. The 3rd party liability coverage is unlimited - the insurance company demand knowledge of all modifications to standard and have approved all of mine - they even ask if the bike has stickers/graphics and what types, as these can make a bike more "attractive" to thieves. They're basically interested in anything which they can say might be a "contributing factor" in any incident (accident/theft) and will increase the premium, or refuse to cover for, anything they don't like (such as "fork extenders" - which is why I couldn't use GSXR 1000 forks

as Fred has done).
Loud exhausts, which are not "stamped" as road legal with factory markings are not covered either and can invalidate insurance in the case of a claim (except where noise test compliance was not required when new, basically on bikes made before 1984 here). However, they consider replacement of parts with ones equivalent to new as acceptable. Top boxes, panniers and other things which change carrying capacity should also be notified. I have a nephew who had his car insurance invalidated because he hadn't informed them of "non-standard" (ie, wider) wheels on his car - they were on when he bought it from the dealer and he didn't even know they weren't standard - it was a Honda Civic Type R, which has "boy racer" wheel from the factory anyway. After a slight accident where he involved the police because the other "at fault" party was being stroppy, he was subsequently charged with "driving without insurance" after the damage assessor identified the wheel issue and they cancelled his insurance cover.
Liz's Fazer 1000 (FZ1) is £108 per year for the same coverage.
Being "old" helps.
The Fazer 600 (FZS 600) is £402 per year, with our 26 year old son as the insured rider, also fully comprehensive etc and with unlimited 3 rd party liability.
These are because we have maximum "no claims discounts" and clean driving licences (touch-wood). They would rise dramatically if we had made prior claims, or had points on our licences.
As we don't have personal medical bills here generally, due to the NHS, I'd guess that's why our 3 rd party liability costs can be unlimited.
But we also have a fixed minimum deductible (known here as a "Policy excess fee") of £450-£500 for theft or damage to our own bikes.