As folks have asked about the valves on these in the past and having found no pictures or exploded diagrams on the net, I thought I'd post one. :-

http://i1138.photobucket.com/albums/...szjtgrun5.jpeg

This is actually the valve out of my Mohawk, I stripped it as there was a velocity variance on one pump as the exhaust valve was closing part way through the pump stroke so varying the pressure in the valve.
I found the culprit straight away as the exhaust valve return spring had collapsed, I'll just lap the valve back in and replace the spring, believe it or not, one off a clothes peg fits.
The inlet valve ball bearing was rusted so I've decided to change that as well seeing as the bearing out of a pushbike wheel is a direct replacement.




All the best Mick