Bar end shifter problem

After removal and reinstallation[1], the shifters seem to have lost
their clicks in the middle three or four gears. It's been a while since
I rode this bike, but if I recall correctly it smartly snapped from gear
to gear. I don't mind friction shifting, but it's a little disorienting
to have this mixture of indexing and friction.

Is there any way that I could have messed up the installation and caused
this? Any cure that I could try? These are Shimano 8-speed.


[1] This was done to allow replacement of the original Mafac Racer brake
levers with up-to-date levers. What a difference! More effective and
more comfortable to boot. The old levers are from the Age of Drillium
(lots of holes) and still have the original gum hoods. If anybody wants
them, I don't.

--
Ted Bennett