Lionheart

I've got a Campy Record 10spd, mechanical RD. The chain is new but is Chorus or possibly Athena. The cassette is not new. My mechanic put on the chain and did some other work. When I got it back the shifting was off. My mechanic has re-adjusted the RD for this issue once already. However, it seems to be one of those issues that persists under load but when the bike's on the workstand it shifts fine.

The Problem:
When I actuate the paddle to shift to a smaller cog the shift does not happen... immediately. If I unload the crank/soft pedal the shift happens after a few revolutions of the crank not under load (perhaps 2-10 revs).
If the shift fails and I hit the paddle a second time, it shifts one cog but then will shift one more cog after a few cranks un-loaded.
Also some times when actuating the large lever to shift up the cassette, to a bigger cog, the chain will engage the cog but after a few seconds might then drop back down to prior cog.

The problem seems to happen regardless which cogs I'm using and regardless of whether I'm in the big or small ring. I attempted to adjust this out myself by rotating my barrel adjuster clockwise (looking at it from the back) a half turn. It seemed to get a little better but persisted. So, I made a few more adjustments, again seemed to get a little better but it's still not right. I just wonder if I'm rotating the barrel adjuster the wrong way. Any suggestions?

13ollocks

Sounds like a sticky cable - you get sluggish and unpredictable "out-shifting". Double-shifting will definitely drop the chain down one sprocket, but it'll then complete the double shift to the next sprocket a little later. Screwing in the barrel adjuster (easing cable tension as you describe) can alleviate this slightly and temporarily, but all it's really doing is messing up the indexing. In my Chorus 10 setup. I change the RD cable about annually, as it starts to fray at the shifter and causes the symptoms you describe. A new cable and resetting the indexing fixes the problem. FWIW the chain is unlikely a factor - I've run Campag, SRAM and now KMC X10 chains for years with no issue - I don't imagine a "lower level" Campag chain would be a problem.

Iride01 

Likely your issue is incidental to the chain being put on. Perhaps your cable has started to bind.

Some of what you describe is what I'd get when the chain is too long. But only when in the small front and going to the 12 and 11 sprocket on the rear. Not for all the gears.

wheelreason

What you describe can be caused by one or more things. Was it working properly before you changed the chain? Since it is not a newish bike, I'd check each possible issue, shifter, cable, dlr, hanger, cassette, and lastly the new chain may be not playing nice with the old cassette, and really lastly, not wanting to shift correctly in either direction might b a screw...