Ok, I must be brain dead...

Here's where the Italvega stands now:



The freewheel is 14-23, 52/42 chainrings. Well within all the acceptable limits for NR RDs from what I read.

In trying to setup the RD I'm running into a couple of problems:

1) If I have enough chain for big-big + 2 it's very slack in little-little, like 3-4 links slack.

2) If I have it at a higher chain angle like 52/23 or one down, the chain rubs inside the pulley cage at the lower jockey wheel. Furthermore the chain seems to dance around the pulleys a lot, as if there's not enough of a tooth to properly capture the chain.

Here's the RD:





Questions:

1) I'm using a 6 speed KMC chain in really nice shape...should I use something different?
2) Is there a trick to setting these guys up over a Suntour RD that I'm just missing?
3) The pulleys have a little wear but every NR RD I see seems to have that tooth profile...are these "normal"?

Thanks!

from your picture, it looks like the lower spring is not doing its job. I think that Sheldon's big/big + 1 link method works pretty well with these.

People keep asking the questions I also need answered. I love this site! I'll be watching this thread, too. Thanks, Khatfull.

I recently set up a NR on my new Frankencilo build (13-21 + 42-53). I have no need for the big-big combo so I set up the chain for the 53-19 combo. I also have no need for the small-small combo and my chain tension is fine on the 42-15 combo.
On initial assembly I noticed the RD was misaligned - apparently the bike had fallen on the crankside in an earlier life, so I had to tweak the hanger gently back into alignment. You might sight the RD from behind when mounted and see if that's part of your issue.

Here's a closeup of the RD/crank cropped out of the full-size pic above. Does this help any? Honestly, I forget what length of chain I have in here in this pics...links were a'flying last night.



And yes, that is a makeshift RD housing until I get a real one...I just wanted to try to get chain length set

I take it you mean cable housing?
Can't tell the alignment from a side pic. Try a rear pic, in line with the chain line in a gear combo where the chain is fairly straight.

I wish I had more experience with older Campy stuff. I have found that on some frames the Campy RD will affix to the drop out solid & not movable. Other frames the Campy RD will hang loose or movable.
Am I assuming that a correctly mounted RD should hang free to move for & aft. The cage spring pulls the chain & RD to the correct position. This requires a pretty strong spring.
Someone correct me if that is incorrect.

Things I always check:

derailleur alignment, in particular dropout hanger alignment. Cage should be in line with freewheel cogs in both up down and front back. Either derailleur cage or hanger can be bent. I find that about 50% of the bikes I work on have bent hangers. I have found very few bent cages. This can cause chain to rub on derailleur cage.

cage spring tension. Many of the older RDs have weakened springs. The spring in cage pivot has two holes in both the pivot cover and the cage. You can move the spring to the other hole(s) to get more tension on the chain in the lower gears.


It would be useful to see a picture of the bike in small-small gears to see how much chain slack the RD is taking up. If chain length is right and spring tension is good RD should be close or to max chain take up in those gears. Can we assume you have checked chainline and that it is in a reasonable range? Your pulleys look fine.

The RD spring is whipped.

Keith, with NO chain installed does the cage 'snap back' when its rotated? It should take a fair amount of effort to rotate the cage by hand and it should easily, if not somewhat forcefully, spring back so that the cage stop is firmly against the derailleur body.

Jim, I'll check it when I get home. My thought was it felt firm but we'll see. Thanks.

The chainline should be reasonable, it's the stock BB and crank for the bike.

I'll check the RD for tension again.

This is a good bet. That is quite a hefty spring in there, and on a Pat '75 RD, could have seen better days.

Keith,

If you decide to try to replace the spring, it appears it is Campy 813/A. campyoldy says they have it.

https://www.campyoldy.co.uk/Minuteria.htm

Oschner may have it, I would think this might be worth the $10 to find out..
https://www.ochsnerusa-store.com/search.php?nobox=&scat=&stext=spring&stype=&sprice=&pg=2

look midway down the page for REAR DER RETURN SPRING REC

Ok, ok, I'll check the spring Thanks guys.

Anyone know of an exploded assembly diagram for one of these things? I'm so used to having them for my Suntour stuff

^ https://www.campyonly.com/history/catalogs.html

Catalog 17a is a good one for most NR/SR stuff...

You know, I suppose I deserve this for being such a Suntour/Shimano guy...

The spring will keep the derailleur body on the stop unless you are getting close to the capacity of the derailleur. It should be able to rotate though, it's pretty hard to remove/replace a wheel without that.

^ but of course

I would probably scratch the Oschner link... when I put it in the shopping cart, it was listed as 7260090, not 7260006 which should be the correct part number for the 813/A.

Whatever the problem, that is one georgous looking NR Campy drivetrain!!

Thanks, like that custom cut NR big ring by our own Drillium Dude?? Italvega did that at the factory evidently:



My polish and fill on the crank. Same with the SR seatpost:

Nice, NR turned semi-SR ! Pretty cool.

You deserve far worse for that offense...

You should be punished by only being allowed to ride Fujis

Be just a bit careful when you remove the "grub screw" 812/1A to remove tension on the spring. Weak or not, there's enough wind up in that cage to surprise you if you let go. Just FWIW FYI. Moving the end of the spring to the other hole may do it for you.

I've broken down, cleaned and reassembled about three or four dozen Suntour RDs...I'm well aware of what happens when you remove the stop pin

Which also means I gotta break that stinkin' chain....again.

Yeah, blah blah...

Just wait until I get the Pro done....maybe THEN I can get you some Fuji envy!!!