Does anyone know if you can change from 105 to 120mm, internally. As reading the manual there seems to be not much difference between the 85, 105 and 120mm models

Not sure but I'd be interested. Have some 105s on my Summer Season and would love an extra bit of length to play with 😉

my old 2004 ones have been converted to 80mm from 100mm. I bought a 20mm marzhocchi spacer from uk bikestore and used this.

Would love to know too

This is the marzocchi mx comp 2006 manual

http://www.wheresweyland.com/images/2006_marzocchi_service_manuals/2006-mx-comp.pdf

On page 18 there is a diagram of the right pumping element. it has a preload tube which is on 105mm models, but not on the 120mm models. this is same with the left pumping element.

I am not sure about this, so I could be wrong. A quick answer would be loco tuning, see what they say. If somebody wants to ask…

Yes, I've done it. I wish I had taken some photos. I will take one of the spacer that I removed.

pcant see the manual but, on the 120mm version the preload tube will be either on top of or directly below the spring?

id imagine there is a preload tube in yours, but its "under" the damping rod. If you take the forks apart and take it out from under the damping rod and stick it on top of it then it should change the travel. It does on my marzocchis anyway

So, where the preload sleeve is under the rebound spring. swap around so that the preload sleeve is on top of the rebound spring

No, preload sleeve is under the rebound spring. Take it out and stick it ontop of the main sping (just below the topcap of the forks)

Job done.

Mine was an 04 model but it looks the same as page 13 in the manual posted above.

Remove bushing (4), valve (5) and three-point ring (6) from the pumping element.
Remove the preload tube (9) (only for models with 105mm travel).
Remove the rebound spring (7).

If you think about it, where it is now, it basically stops the stanchions of the forks from extending fully. Take it out and the stanchions can extend a further 15/20mm (whatever length the sleeve is) but you need to stick it in the top of the legs to make up that difference

hmmmm. so take the sleeve from under the rebound spring and on-top of the rebound spring

Eh,

I cant see the pics n that but:

1 Remove top caps
2 Take out innards
3 Remove lowers & pumping rod
4 Remove sleeve from the pumping rod/near rebound spring
5 Put pumping rod/lowers back together (with the rebound spring in place)
6 Put the main spring back in
7 Just before you pour the oil in and put the top cap on, put the sleeve on top of the main spring

sorted

mine are air, so i put it on top of the rebound spring

Remove bushing (4), the rebound spring (7) and the preload tube (9) (only for models with 105mm
travel) from the pumping element.

swap around

If I remember correctly I removed the spacer completely and the air in the other leg is enough to fully extend the fork(spring still has some pre-load). I am fairly light at 12st, though, so it might be good to re position the spacer to add spring pre-load if you are a heavier rider.

good work guys, you just saved me hundreds of pounds 😛

All done, spacer removed and they are 120 now 🙂

When i took them apart, i was shocked by the build quality of the push rods and stuff. Crap stuff.

Just get my rebound sorted now and they are a bit sticky! Not sure why.

What sort of air pressure, i usually have 50 psi in each side for a 95kg rider. is that a bit ott

bump

If you used Silkolene motorbike fork oil, that causes some stickyness – I believe there's a seal swell additive in it. Changing it for something else helps a lot..

By far the biggest improvement I've found on my old Air marzocchis was to pull the stanchions out, put fresh oil and then then lube the seals with brake caliper seal grease. It's rubber safe and made a massive difference to the stiction.

Yeah i am using silkolene 5wt, dam expensive stuff and dont want to take them apart again. now to sort out my rebound and sensitivity

rebounds a pita with them due to needing the three foot long allen key!! 😉 took a good few goes to get mine set back nice after doing the travel, but then, the small plastic white 3/4 washer bit on the top of the right leg had broken on mine, that didnt help.
Love my old bombers though,

i'm pretty much the same weighjt as you and ran 55/60psi in mine, (95 kg ish!)

IIRC Marzocchis all take 7.5wt as standard. A mate's fairly light so I set him up with a 50:50 mix of of 5 and 7.5wt – probably works out at about 6.5wt.

If you're around 100kilos, you'll be in the 7.5wt range. And getting rid of silkolene oil made a big difference to my forks.

what oil should i put in them

this:

http://www.chainreactioncycles.com/Models.aspx?PartnerID=79&ModelID=112

Marzocchi tend to give a rider weight of 155lbs as the upper limit for 5wt oil, 145lbs as the lower limit for 7.5wt, and 220lbs as the upper limit for 7.5, with 210lbs as the lower limit for 10wt, but it does vary a little from fork to fork – have a ride and see how the damping is.

Oil viscosity also varies manufacturer to manufacturer! 🙄

I've found Rock oil SVT to be OK, and you can pick it up for about £8 a litre from motorbike shops – same stuff is sold for motorbikes and pushbikes.

I find my marzocchi's now are sticky and less sensitive. What to do, as i have used that sikolene 5wt oil. maybe use stendec oil or something?

I think that's what you call a non sequitur…. 🙂

What to do

Pull the stanchions out and change the oil for a different one. Cleaning the seals and using a little fork grease / rubber grease on the seals really helps too.

I've found that the seals get back to normal fairly easily – presumably the seal swell stuff diffuses into the new oil & grease over time, so the seals recover.

so if i put in a 7.5wt oil, they be fine and not to use silkolene and fiddle around with the rebound

Aye. I previously used Silkolene in my Z4s. Swapped the oil and used a bit of grease as above and they’re much better.