I have an XR250 in the garage which gets dragged out now and again for a play. Looking for a really basic policy to cover myself and also the kids (24 & 21) if they come home for the weekend. Not bothered about fully comp or clothing cover etc.
Just get on the phone to all the many brokers / insurers who ply their trade via the pages of MCN and / or at the multiple names that keep on cropping up on these pages (best or worse views on each will vary) and settle on the best YOU can find to suit YOUR unique circumstances.
You could, I guess start with your current insurer of your other bike(s) or get one of your sons to arrange it, sparing yourself the effort.
On recommendation from here, I tried Footman James who say that it has to be 15 years old. They then declined to quote online without explaining why. I called them up and, apparently, to have under 25s on the policy, the bike will need to be 20 years old!
I've been using a trade policy for years and looking ahead to a time when I might decide to put my feet up, I thought I'd start building up some no claims on something cheap. The last time I had a bike policy in my own name it was a Devitt DA Rider policy for £12.50 a year.