Fork oil change

[Ian]

OK, progress report. The second fork has been draining for 2 days and has been thoroughly pumped. It’s as empty of oil as it is ever going to be without completely disassembling it. I filled it with 435ml of oil per the book. Pumped it 12 times and measured the air gap. It was exactly 115mm. I’m now going to leave it a couple of hours for any bubbles to come out and then re-measure the air gap. It will be interesting to see if there is a difference. After than I’m going to set the first fork I did to the same air gap. Sometimes it’s tedious being a perfectionist!

 

Thanks for all the advice people gave btw.

[swooshdave]

Pictures! If only to keep us more entertained with your adventures.

[Ian]

Not worked out how to take pictures and shrink them in size to fit within the forum limits. Anyone know how to do this?

 

Anyways, re checked the air gap on the second fork (the one with 435ml in it) and found that after leaving it to settle for 3 hours it had increased from 115mm to 118mm.

 

I then took oil out of the other fork so that both are now nob on 118mm and I’ll check them again in the morning before putting the springs and cap back in.

[docc]

Not worked out how to take pictures and shrink them in size to fit within the forum limits. Anyone know how to do this?

I host all my images on ImgZeit. Especially images that viewers can make large and see excellent detail.

 

https://imgzeit.com/tour

[nobleswood]

Did you get an answer to the nut on the cap assembly question you posted a pic of ?

 

Cryptic I know but Ian knows what I’m talking about

[footgoose]

 

Not worked out how to take pictures and shrink them in size to fit within the forum limits. Anyone know how to do this?

I host all my images on ImgZeit. Especially images that viewers can make large and see excellent detail.

 

https://imgzeit.com/tour

 

 

 

  me too. imgzeit is cheap, no frills, and happy to serve... just like yer guzzi

 

couple of guys doing a leg of the TAT, visited us at '17 Spine Raid

 

[Ian]

Job done. I lied last night when I said the air gap had increased from 115mm to 118mm after a couple of hours. Idiot me used a 3mm piece of steel on top of the stanchion to give me a firm datum point to measure the air gap from and my tired brain forgot to subtract 3mm from the measurement.

 

So for all those who follow, if you are doing a fork oil change on the 43mm dia. Marzocchi fork, you need to drain them thoroughly by pumping the cartridge a dozen or so times and then leave overnight to drain some more. You then need to add 435ml of new oil which will give you an air gap of precisely 115mm.

 

The forks are back on the bike now and the damping feels smooth and consistent. Have some more servicing to complete before riding it though.

[Ian]

In reply to nobleswoods question. When I pulled the caps I found the nut fully backed off per the photo and the cap was just screwed down as far as it would go on the cartridge rod I.e the nut was not touching it and not performing the locking function it is supposed to do.

 

On reassembly I wound the caps down until they bottomed out on the cartridge rod and then I wound the nut upwards to lock the cap in place on the rod. This is how they are supposed to be.

 

I can confirm that I got the full range of adjustment on the clickers and that they work as intended (preload and rebound)

[Gio]

Glad to read that you got this sorted Ian ... seems that, barring any previous leaks or otherwise missing oil, patient measuring of removed oil volume is a reasonable place to start (with reference to spec volume - 400 in my case, 435 in yours) ... nothing wrong in perfection, if attainable ... methinks!

[LowRyter]

the big question:

 

if the seals aren't leaking should I bother with service?

 

I say, no.

 

I need guidance and advice.

[docc]

the big question:

 

if the seals aren't leaking should I bother with service?

 

I say, no.

 

I need guidance and advice.

Fresh oil is always good. It is just not so easy as an oil change. Especially on a Sport that all the clip-ons, and instruments, and headlamp/turn signals are mounted to the forks which have to come off to dump the oil/ "no "drain")

 

Gotta tie her up. But, she digs it. No, really . . .

[LowRyter]

Docc, Always good.  I suppose.  There is no combustion and the forks are sealed from dirt and grime. 

 

It's a total PIA to do.  I only do it to change out the seals and bushings.  Since there is no expected life limits on those items, I only do it when I see a leaky seal or felt that the fork action isn't responsive.  The only time I wanted a fork apart that wasn't leaking was on my Bandit, it was upgraded with better springs and Race Tech gold valves, made a huge difference. The Greenie seems better to me than the after the Suzuki was upgraded. 

 

Anyway, I am ordering a new rear shock, working on oil leaks and wondering about the servicing the fork that isn't leaking. I am still of the opinion "if it ain't broke...."

[czakky]

I would disagree, oil has long chain molecules that are broken losing viscosity.

 

Watch old fork oil being poured out, like water. New oil is usually much thicker.

[LowRyter]

Good point, CZ.   The oil is beaten like a scrambled egg.  I would assume once the oil is broken down that fork is a little wimpy?

[Chuck]

To add to the above, there *is* wear. I'm not familiar with the forks in the greenie, but if they work the same way as the Mighty Scura and the Centauro, it definitely needs changed. It will be black from aluminum particles. A sealed cartridge fork, maybe not so much.