"Gary" wrote in message
oups.com...
Popet valves and thier seats, springs, retainers, ect. cost a lot more
than simple reed valves. More material and more machining.

And easier to service and repair. My old (no, ancient - 1963) two-stage
pump leaked like a seive when I got it (free, on a rusted-out tank). It
took only about an hour to re-face the three leaky valves, and get the thing
pumping like new again. It still had some of the honing cross-hatch on the
cylinder walls!

LLoyd