LM3 Fork Spring Replacement

My 40 years old LM3 forks bottom out. I would like to replace the original springs for something stiffer.

Gutsibits has two options, which would be stiffer?

  • Guzzi heavy duty
  • Wirth progressive spring
    I could also add spacers to reduce the sag as I’m 210 lb.

I’ll inspect the original fork dampers condition but not planning on changing them if I don’t have to. If do need to, would probably go for FAC.

I haven’t taken these forks apart before.
Is it possible to remove the damper and spring from the top while still in the triple clamp by loosening the bolt on the bottom of the leg?
The fork seals are fine so ideally would not even want to remove the bottom fork legs.
I’d like to plan a quick turnaround for the job. Is this possible?

I think in theory you can pull the inners out in situ, the issue has always been for me getting the top caps off, on the mk3 there isn’t much room.

I was hoping to avoid the job of removing the stanchions from the tree clamps & clipons. That’s the bit I’m not looking forward too. The bike is in current use and would like to plan a job not a project lol.

You can remove the internals without removing the stanchions, using the method you suggest. HOWEVER, I’d doubt that the forks would bottom, even with tired springs and so it might be that the dampers are suffering.

Personally, i always drop the legs as it’s less hassle - using the yokes as a clamp to loosen the top nut is a good idea, but then i always clamp the lower in the vice to remove the bottom allen bolt.

Always worth replacing the oil seals - i swear by Ariete - and remember that the forks only need 60-70cc of ATF to lubcricate the motion, as the damping is all done by the cartridges.

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Hello Steph, strange I was only doing this yesterday on my Spada and I think the forks are similar.
You can leave the forks in place but will need to remove the wheel and brake calipers as the cartridge is attached through the bottom of the fork leg, new ally washers are advised.
Once the top caps have been loosened put a rachet strap around the bottom yolk and the caliper bolts, this will stop the legs from dropping and gives you a bit more control.
When the bottom screws are removed I was surprised what came out, so use a large catch tray. You will need a set of small circlips pliers to remove the springs from the cartridges put a cloth over both as the circlips will go into orbit, you can now test the dampers.
The replacement is the reverse but it is helpful if you have a second pair of hands when fitting the circlips,
Good luck, Roy

When the forks are loaded up by braking and then you hit a pothole (poor roads here) the forks do bottom out.

I’m tempted to try in situ when I have time.

I do like the current spring rate on the motorway, very compliant and comfortable. I’m now debating if I should not just add some spacers to create some preload.
Not sure if the Guzzi Heavy Duty ( 1st preference) or Wirth progressive spring would be best for me.

Thanks for all the replies