robertj298 

It seems that no matter what gear it is in the main pivot on the derailleur is sprung all the way out not putting
and tension on the chain. The spring seems ok but the derailleur is horizontal with no tension on the chain

canklecat

Got a photo? Sounds like the cage stop screw came out, or the cage pivoted around the stop screw. Or the lower knuckle spring popped out or broke. Might be a relatively easy fix.

robertj298 

Ok here's a photo. The derailleur is turned all the way counter clockwise with no tension on the spring.I can turn it clockwise and feel the spring tension. The b screw does not do anything no matter which way I turn it.

madpogue 

First thing I'd do is measure the chain for wear. Look how it's not fully engaged on the freewheel cog except at the top.

79pmooney

[QUOTE=robertj298;21039291]Ok here's a photo. The derailleur is turned all the way counter clockwise with no tension on the spring.I can turn it clockwise and feel the spring tension. The b screw does not do anything no matter which way I turn it.

Are you talking about the spring at the bolt to the dropout hanger? Does this SunTour even have a spring there? Many do not, unlike Shimanos and at least some Campys. Second question - what kind of dropout is that on the frame? If it is the French Heuret or Simplex, it may well be designed for the French derailleurs and their "B" screws. If so, a Campy (Japanese) standard derailleur "B" screw will not engage the hanger stop and the derailleur will rotate as far forward as possible.

It is possible to make adapters to make the French standard dropout work, either as an added and removable piece or with a brazing torch. I made a removable piece (true pain-in-the-*** then had a framebuilder do the change. Far better! Or you could find an older Simplex or Heuret derailleur.

Ben

robertj298 

That makes sense but it's a new chain and it worked when I first put it on.

robertj298 

[QUOTE=79pmooney;21039340]Yes there's a spring. I'm not sure about the dropout. I assume it's the original suntour dropout. Everything is original on the bike

madpogue 

Well there's somethng wrong with the way the chain is engaging the cog. That shouldn't depend on chain tension.

79pmooney

The dropout is SunTour? SunTour did make dropouts (the steel piece of the frame brazed to the seat and chainstays that the hub axle slides into and the derailleur is hung from) but a lot of of bikes that came with SunTour derailleurs did not have SunTour dropouts. Probably close to zero frames made in Europe. Your dropout looks like the short Simplex dropout on my ~1990 Peugeot frame. (I never put a derailleur on that frame so I do not know if it is French or Campy/Japanese standard. Is probably the latter. Most of that frame was English standard and threading, but not all.)

What is your bike? Model and year?

Edit: another thought - that derailleur may have a spring that is or should be wound up to pull the derailleur back. I haven't dealt with such a derailleur for a while so I don't remember the steps but it requires (to the best of my memory) backing off a nut on the inside of the derailleur on the pivot bolt, winding the bolt and spring back with a 5mm (?) hex wrench, then re-tightening the nut. Look carefully at the derailleur (preferably off the bike) at that pivot bolts and see if there is a nut on the bike side that, if backed off, gives access to a spring. Now tightening the spring may well be easier on the bike and it frees up a hand. (Like I say, it's been a few years so my memory is poor. I may well have ended up concluding I don't like GPX derailleurs.)

Ben

canklecat

Cable is in the wrong position in the clamp bolt. It should be behind the bolt. Check for the indent in the clamping bits to see where the cable should be clamped. That'll affect everything -- how it runs and shifts.

Needs a new cable that isn't frayed too.

canklecat

Here's how it should look.
Cable goes behind clamp bolt from this perspective.