Marzocchi shock absorbers

[3potjohn]

I am looking for a pair of the rubber bump stops as fitted to the ancient Marzocchi rear shocks. Measuring the now falling apart old ones I have 32mmOD, 22mm in height with a damper shaft diameter of 7mm.
I have disassembled them using, in what might be called a health and safety nightmare, baler twine and 2 screwdrivers.
I know you would not consider rebuilding 37 year old car shocks but there you go.That’s retirement for you.What else to do with 2.5 wt racing oil.I make it 60mL per side? Or is it 80mL?
Any ideas on a source? Must be similar on other shocks one would think.
John

[mbmm350s]

Hello John

Zanardini has all the overhaul kits.

www.suspensionzana.com

Mark

[3potjohn]

That’s really useful. Thanks very much.
John

[themoudie]

Aye John,

Ironically a similar thread was started on the Ducati singles forum today. So, having shared Mark's source of spare parts (and duly credited), with the enquirer there, I thought that rather than the "baler twine and two screwdrivers" you might be safer with George's spring compressor that he suggests using. George is from Northern Ireland and does a wee bit of this and that with Ducati singles, appears at Stafford as well and is good craic.

Georges' Marzocchi rear shock absorber spring compressor quote.

So these shocks are held together by the spring preload adjuster system at the bottom of the unit, you have a bottom sleeve with the adjuster wire handle, then you have a top sleeve above this under the bottom of the spring, if you compress the spring under this top sleeve there are three ball bearings that run in a rising track in the shock body to facilitate preload adjustment....but these three ball bearings also retain the spring, so with the spring compressed and the top sleeve raised the balls will fall out and the spring is free to remove. Long ago I made a spring compressor for ducati rear shock springs utilising a heavy duty silicone cartridge skeleton driver gun, just cut a segment out of the front flange of the skeleton gun big enough to slip through the bottom coils of the spring and big enough to clear the shock body, put a rubber pad on the plate end of the driver rod to save damaging the top of the shock mounting eye ..........ratchet the skeleton gun up just as with a cartridge fitted and this will compress the spring ......works a treat just be careful to use a well made skeleton gun, a cheap rubbish one will just break unexpectedly and possibly injure you

I hope this helps and enables you to keep your finger tips!

Good health, Bill

[3potjohn]

The Marzocchis ( I believe type A73?) have a slotted spring retaining plate which is removed once the spring is compressed.
On my old Boge shocks on my Beemers you just grasp the spring, force it down slightly then unscrew the top from the damper rod. Much easier, however this unscrewing can occur on the road too which causes a sort of buttock clenching effect.
John

[themoudie]

Morning John,

however this unscrewing can occur on the road too which causes a sort of buttock clenching effect.

The art of understatement!

Good health, Bill

[morini_tom]

John, are you sure your damper rod diameter is 7mm? Mine are 9mm.

Funnily enough last week I ordered the overhaul kit which includes new top nuts from suzpensionzana (at least I hope it was the right kit now!)

http://www.suspensionzana.com/index.php ... Itemid=114

[3potjohn]

Yes they are 9mm. I remeasured them earlier using my proper Aldi caliper, rather than a B&Q tape measure. Those top nuts look good.Many years ago I tried separating some others I have. Not a roaring success.
What oil will you use?
John

[AntietamClassicCycle]

Just rebuilt mine a few months ago. Kits from Ugo Zanardini, 5w oil using this information from Ugo as a guide for the amount:

Hello,
for interasse 290 mm e 300 mm = 70 cc olio per ogni ammortizzatore .
For interasse 315 mm e 330 mm = 75 cc per ogni ammortizzatore

Buona serata

[P&S]

This might help:
https://www.rpw.it/Files/Marzocchi%20A7 ... %20UEM.pdf

[themoudie]

Thank you for sharing "P&S", I have shared this with the Ducati singles forum and credited yourself for providing it.

Good health, Bill

[P&S]

Ciao Bill, you can also share this old post.

https://motomoriniclub.forumcommunity.net/?t=56189893

Saluti, Paolo

[Ming]

Ciao Paolo. Thank you for sharing that link, I'm sure it will be useful to quite a few of us.

[themoudie]

ciao Paolo, grazie per aver condiviso queste informazioni aggiuntive e le immagini molto chiare dei componenti degli ammortizzatori, insieme ai processi di lavorazione.
Saluti, Bill

That is 'Google' translate's attempt at what I wished to say. Here is the original: "ciao Paolo, thank you for sharing this additional information and the very clear images of the shock absorbers components, along with the machining processes.
Saluti, Bill"