That was the 'official' line, that the pumping cylinder didn't pull in fuel during its induction stroke and just pumped air, but 70's Facebook forums (your biker mates in the pub basically  ) thought otherwise. I can't say I ever remember sniffing the tyre valve to check but we did use one a few times on mini bus / van trips until it fell apart. It was a bit slow but it did work.
The Japanese used to supply hand pumps with some of their early bikes - mainly 60's stuff but I do remember a couple of early 70's Suzukis coming with them. The frame on my 1970 Yamaha 250 has the lugs for a pump but they stopped including the actual pump with the previous model. Whenever I look at that part of the frame I wonder about how much job satisfaction some Japanese welder got knowing that his day was spent doing something completely pointless.
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