Zeus Criterium rear DR problems

[Johnsco]

The rear DR on my old Carlton has been troublesome ever since I got the bike back on the road after 30 years+ in the garage after my mate had trashed it.
It's always been difficult to get the chain tension right over the range of the 5-speed freewheel.
I've frigged it by positioning the DR hanger in the "wrong" position.
It's worked, but I've never been happy with it.
The top pivot where the DR mech is mounted to the frame is sloppy .... I would have expected it to be spring-loaded but it is not.
At first, I just accepted this - However - On thinking about it, it makes no sense.
I had a look thru Sheldon-Brown.
https://www.sheldonbrown.com/derailer-adjustment.html
This seems to confirm my thoughts that the top pivot (the one that SB calls "angle B tension adjuster") should be spring-loaded in order to expand the range over which the chain is tensioned.
By the way - The chain is the correct length - as per Sheldon-Brown.
There is no spring tension at all.
There does not appear to be any adjuster.

There is an allen-key slot in the front of the pivots.
Does this unscrew ?
Does anyone have a diagram ?
See photo .... Yes - I know that it's mounted incorrectly.
This is a shabby compromise to make it function at all.

It may be that the DR mech is goosed.
Maybe time to mend it with another.
Your thoughts would be greatly welcomed..
Thanks.

 

[Sharky]

I googled some other images of zeus rd's and the jockey wheels were rotated clockwise more, so that the top jockey wheel is quite a bit forward of the lower jockey wheel.
Are the jockey wheels spring loaded?

 

[Sharky]

.. What does it look like, when it's on the small sprocket?

 

[Cycleops]

I should just swap it out, the Campag Gran Sport is pretty similar and I believe there was some tie up between Zeus and Campag. Plenty of good used ones on eBay.

 

[weareHKR]

First thing you need to do is get it mounted correctly, no point in messing around with until that's sorted out!

 

[Johnsco]

Thank you all for your helpful replies and comments.
Here's a photo of the mech when it's on the small sprocket:

Regarding mounting it properly, it won't tension the chain if mounted correctly - That's why I've frigged the position to get it to work at all.

The jockey-wheel cage is spring-loaded.
It's the top pivot that I think should be spring-loaded, but it is not.

As Cycleops says - Perhaps it's time to mend it with another.
The Zeus unit that I have appears to be a rip-off of the better-known Campag.
They are clearly very-much the same geometry and everything.
Thanks for your thoughts, so far.

 

[Ajax Bay]

When I've had my 'Patent 74' Nuovo Record RD apart, there's a spring to twist the cage round and (from memory) one end is lodged in a hole. But you have to wind the cage right up before putting the bolt back in and tightening (the cage 'axis'). If the Zeus has a similar mechanism, that might solve your ineffective wrap issue.

 

[Johnsco]

Thanks Ajax Bay.
That's what I rather suspected might be the case.
This is the top mounting pivot rather than the end that the cage twists around.
I can't see any logical reason for the top mounting that fastens to the hanger bracket not to be spring-loaded.
Otherwise - It might just as well be tightened-up and set in a fixed position.
On mine, it is completely slack and the mech just swings like a pendulum if you take the chain off.
I'll try to get it apart and see if it can be repaired.
If not - Then it's definitely time to mend it with a new 'un.