Yet another difference between Ontario, Canada and Ontario, California, Gregorymoto

Notarized for DMV purposes is merely completing their form.
Here's how its done....
Most states have a "quick title" or otherwise known as abandoned vehicle title service through the vehicle registration department. They should be able to advise you.
You can use a lean-sale company to initiate a lean on the bike in lieu of theoretical storage fees. When the bike defaults the lean it is issued a new title in the lien holder's name (you.) For expensive bikes it takes about 3 months. For less expensive bikes it takes about a month. The lien sale company charges you a small fee (e.g. $80).
You can also initiate the lien yourself but the process is a little more difficult. The waiting period is to see if the actual owner of the property steps up and claims the bike, or contests the lien. They send notification to the address on the last title holder.
Since you know the holder is on record, that is what MUST be done. You would still have to go through a lien sale process even if the bike is not registered with the state.