tank without key

I am re-habbing a '79 B2. I don't have a key for the tank. I had read online that 1970s Kawi's had no pins/wafers in the tank lock, and "any key" would work. But all the spare keys in my drawer are too thick.

I'd like to take the tank cap off, and take to the hardware store to try blank keys. If I remove the hinge pin from the lock, will I be able to pull it from the tank?

Pretty much any thin bladed screw driver or the ignition key will open it. It only needs to be thin enough to fit down the lock.

Just seen your edit. Yes that would work also.

I played around with various screwdrivers. I finally took-out the hinge pin, and took the lid to the hardware store. I found about 5 different key blanks which seemed to fit-in until they hit the back of the lock, but none would turn the lock at all. It felt as though the lock had pins/wafers. Very odd. FYI, when I push-aside the lock cover, the key hole sitsleft-to-right; not front-to-back (not sure whit is "normal").

I tried taking apart the lock from the back, but did not find a lock "cylinder" with wafers or pins at all.

Front to back is the lock closed psition. Across the bike is the lock open position. With the lock "open" the tab that springs out and locks,against the underside of the tank filler lip should be withdrawn back into the lock to allow the the cap to lift open.
Now you have the cap off can you spring the tab in and out? If it is stuck out in the locked position and the key slot orientation is across the bike sounds like something has come sdrift inside the lock itself.
I've never taken one apart to that extent so can't suggest whats come adrift but try liberal lubrication with penetrating fluid and leaving for a day or two, if no joy then take apart as much as you can and see what you find. Its buggered anyway so nothing ventured nothing gained.

Thanks, that's very helpful (that the keyhole normally sits front-to-back). To open it, do you turn it clockwise or counter-clockwise?

Clockwise.

ONLY A FEW PARTS IN THERE TO GET MESSED UP.  

This one had the walls on the cap body that the latch rides against pinching the latch, so it would not slide.

SpecialGreen wrote: Thanks, that's very helpful (that the keyhole normally sits front-to-back). To open it, do you turn it clockwise or counter-clockwise?

As others have already stated, it turns clockwise. The key for my astro van also opens my gas tank. perhaps a heavy shot of WD up under into the mechanism / latch, then simultaneously push down on the front of the gas cap while turning the lock to the right might help. It may just be stuck.