Author Topic: Spronging forks question  (Read 122 times)

Offline antoni

  • Advanced Member
  • ***
  • Posts: 36
  • Karma: +0/-0
    • View Profile
    • Email
Spronging forks question
« on: May 12, 2019, 11:08:28 AM »
Finally got a 50s 500 single. Itsa Bitsa. '55 AJS 18S with a '53 G80 engine and knackered Girling shocks. Love it.

Had been re-built but not used. Oh the joy. Pattern parts falling apart, dropping off, hitting other parts, wrongly positioned, breaking etc.

There's a strong sound of springs spronging as the forks are worked. There is a red oil in the forks which will be replaced shortly.  Is this sound a portent of doom or just one of those things?

The G80 engine has an AJ timing chain cover with a bulge at the mag end. Is that where an AJ auto advance mechanism should be? This G80 engine is manual advance (as it would have been).

On a '55 AJ what kind of headlamp nacelle and speedo mount should be fitted?  The present pattern set-up works but is wrong and a little ugly.

Are the Girling shocks repairable - they just act as springs at the moment. I'm assuming this bike should not have candle-sticks or Girlings, but  jam-pots . Anybody got any?
« Last Edit: May 12, 2019, 11:14:00 AM by antoni »

Offline iansoady

  • Advanced Member
  • ***
  • Posts: 473
  • Karma: +5/-0
    • View Profile
    • Email
Re: Spronging forks question
« Reply #1 on: May 12, 2019, 11:19:04 AM »
Those forks are easy enough to strip. That's what I would do just in case there's a broken spring (or sprong if you prefer) or the like in there.
Ian
1952 Norton ES2
1982 Moto Guzzi V50

Offline john.k

  • Advanced Member
  • ***
  • Posts: 296
  • Karma: +2/-0
    • View Profile
    • Email
Re: Spronging forks question
« Reply #2 on: May 12, 2019, 12:32:15 PM »
I would think that by 55,there should be the girling units ,but with the alloy forked cast lower end.........I assume the ally emds are threaded onto the girling  shocks..............You cant fit standard girlings ,as the mounts are different........The red oil will be Dexron autrans fluid........which is what I use........I find that Matchless forks have stanchions of vry soft steel,and easily bendable.................with the advantage ,easily straightenable,without worry about cracking heat treated  high carbon steel,like BSA s......seals are no problem......but wear in the alloy sliders is.......if worn excessively,they will need to be replaced........seen prices for new of around 200 quid each......kinds steep.

Offline antoni

  • Advanced Member
  • ***
  • Posts: 36
  • Karma: +0/-0
    • View Profile
    • Email
Re: Spronging forks question
« Reply #3 on: May 12, 2019, 12:39:22 PM »
Thanks for the info.

The Girlings' bottom ends are forked. They are also f*#ed.

Are they de$%^&&able?

Offline R

  • Advanced Member
  • ***
  • Posts: 908
  • Karma: +20/-8
    • View Profile
Re: Spronging forks question
« Reply #4 on: May 12, 2019, 11:33:43 PM »
There is a shop near me that can cut those shocks open, rework and regas them and reweld them up.
Had a set done ages ago, and they are great - they hard chrome and regrind the shafts too.
These guys get everything they can handle...
But you may have trouble finding such a place - they exist, but are hard to find ?
Ask around businesses in your area, motorcycle shops especially.


Offline john.k

  • Advanced Member
  • ***
  • Posts: 296
  • Karma: +2/-0
    • View Profile
    • Email
Re: Spronging forks question
« Reply #5 on: May 13, 2019, 09:57:00 AM »
Join the Owners Club.......very likely they are remanufacturing hard to find items,and certainly will know where to find stuff.Im pretty sure they have a forum,where you could ask ,even if not a member of the club........which you should be.

Offline iansoady

  • Advanced Member
  • ***
  • Posts: 473
  • Karma: +5/-0
    • View Profile
    • Email
Re: Spronging forks question
« Reply #6 on: May 13, 2019, 11:50:53 AM »
They do indeed have an excellent forum: http://www.jampot.com/forum/. The club is very good.

A couple of other useful links: http://www.amcclassicspares.com/ have huge quantities of used spares; Christian's archive at http://archives.jampot.dk/ has all the manuals etc you could ever need.
Ian
1952 Norton ES2
1982 Moto Guzzi V50