Even when I have a bike that is not running
I still register it every year otherwise have to pay registration PLUS
6% sales tax all over again.
That sucks. Here in Ontario we only pay tax when the ownership changes, i.e. when it is first registered after the transfer. Legally,

you are required to register a vehicle within so many days of a transfer of ownership, but many "collectors" of old vehicles (especially motorcycles) don't bother to do this as it just means you get dinged with the tax. If the vehicle doesn't have a safety certificate stating that it is roadworthy, then an ownership registration is issued as "UNFIT" meaning that it is registered but cannot be licensed for the road until a certificate is obtained. If the vehicle has a "FIT" ownership certificate, then a license to operate it on the road can be purchased at a later date.
Back to the fact that many bikes get exchanged by collectors without registration

, it means that often old bikes show up without ownership, making registration and licensing more challenging. Let's see, how many CB750's in my garage do I have

and this one over here with the license plate and insurance works fine

, but I really would really like to test this one that I just acquired and fixed up

and show it off to the guys at our breakfast meet

.
P.S. I don't have a CB750 SOHC in my collection, and I'll have to plead the fifth.