Originally Posted by el twe
No, the frame's spaced at 126. I had heard that the Nuovo Record rear der can be picky with the wheel too close up. I'll probably take it into the LBS where I work tomorrow and see if there are any other suggestions.
Double check by hand the chain completely for a stiff link(s).
Check the derailluer hanger for alignment, often out by the way. The Shimano tool is best, from the SIS days.
Checking the cogs carefully, for bent teeth as stated and Cupping, depending on the ratio, that can happen to Reginas if somone attempted to take them apart, note the intercog spacing adjacent and between to all troubled cogs, its micrometer time. It can be very slight.
Unless you know the history of the freewheel personally, even a slightly used unit when run with a stretched chain can cause havoc.
Check the rear derailluer for alignment, best test is with the jockey wheels removed and with the parallellogram spring out, I have seen units that "look" good be bent from a wreck and or botched shift, rare, but what can happen is that at certian angles of the cage to the freewheel, the jockey wheels are not in alignment and the skipping is an "autoshift" in progress.