Filling Marzocchi cartridges with oil/bleeding the air out

[motodoc]

I just got a 1999 750 Monster.  It's a BLAST!  The forks, especially the right fork leg leaked oil, so I went to my trusty machinist to replace the fork seals.  Overall it's an easy job; however, I can't seem to bleed that air out of the cartridge and/or get the fork oil into the cartridge.  I'd say I might have the cartridge ~ 25% filled with oil.  I have the stock Marzocchi 40mm forks.  Throwing them away is not an option (though I've seen many comments on the "junk" Marzocchis).  At any rate, if anyone knows of any tricks to bleed the air out of the Marzocchi forks, ANY information would be GREATLY appreciated!   

Thanks in advance!

Jack

[BK_856er]

What's your bleeding technique and what's your oil level and type?  If the oil level is too low you'll just draw in new air with each stroke.

I never got a chance to bleed my OE cartridges - I replaced them with some adjustable Matris cartridges.  For those I have a tool that threads onto the shaft so it can be easily stroked through its range until all air is expelled.  Easy to feel when the air is gone.

Sometimes the OE Marz. forks are configured differently in each leg, so be aware that the bleed behavior might differ for each side.

I'm sure someone who's been into more Marz. internals than me will be along shortly....

BK

[brad black]

support the fork by the lower section somehow.

slide the outer tube all the way down.

pour 400ml or so of oil into the tube.

slide the outer up and down a few times.

grab the end of the damping rod (I screw a tube onto it) and move it the full length of travel in each direction (pull up hard, push down easy) 15 or 20 times.

set oil level.

easy.

[motodoc]

Thanks for the tips!  The fork leg is currently sitting in a vise clamped at the bottom.  The inner tube is filled with oil almost to the top.  I have worked the damping rod up and down many times (almost excessively).  I haven't necessarily tried moving the outer tube up and down.  I'll try that. Currently the outer tube is all the way bottomed out.  I'll lift it up.

Thanks again!  I'll keep you posted.  I'll post a picture of my new Duc soon!

Jack

[motodoc]

Another comment or insight.  These forks appear to be unlike anything I've been able to find in tech books.  As I said in my original post, I'm doing the job at a machine shop where I have a lot of machine work done (restoring a 1979 Honda Elsinore..which was sold to buy the Monster).  The machinist has a shop manual from Race Tech.  Even THAT book does not show the style of fork that is on my Monster.  All the illustrated forks show that the cap is screwed to the damping rod.  On mine the cap is completely separate, and the damping rod is retained by a unit that is almost identical to a valve spring retainer (i.e. two clips that set in a groove on the damping rod with an aluminum (aluminium) piece that holds the clips in place with the spring exerting upward force to hold the works together).

I have to move the damping rod by hand.

Also, from a different post and/or forum (sorry, can't remember) the cartridges appear to be permanently placed in the fork tube.  What I read said they are actually pressed into the fork tube.  Sounds like an expensive thing to do in the manufacturing process to me...but what do I know?

Thanks again!

Jack

[BK_856er]

Cartridges are held in by a bolt on the bottom of the fork.  Remove the bolt to remove the cartridge, although there is no reason to do so for a fluid change/bleed.

It's the "cartridge" itself that is stamped together, so it requires cutting to get inside of it.

There's no external preload adjustment, so no attachment of the rod to the fork cap is required.

Components of mine shown below.

BK

[ducpainter]

Another comment or insight.  These forks appear to be unlike anything I've been able to find in tech books.  As I said in my original post, I'm doing the job at a machine shop where I have a lot of machine work done (restoring a 1979 Honda Elsinore..which was sold to buy the Monster).  The machinist has a shop manual from Race Tech.  Even THAT book does not show the style of fork that is on my Monster.  All the illustrated forks show that the cap is screwed to the damping rod.  On mine the cap is completely separate, and the damping rod is retained by a unit that is almost identical to a valve spring retainer (i.e. two clips that set in a groove on the damping rod with an aluminum (aluminium) piece that holds the clips in place with the spring exerting upward force to hold the works together).

I have to move the damping rod by hand.

Also, from a different post and/or forum (sorry, can't remember) the cartridges appear to be permanently placed in the fork tube.  What I read said they are actually pressed into the fork tube.  Sounds like an expensive thing to do in the manufacturing process to me...but what do I know?

Thanks again!

Jack

Race-Tech doesn't talk about Marzocchi because they don't sell a product for those forks.

Like BK says, the cartridge assy is removable, but not serviceable on those forks.

[motodoc]

One of the first things I did was to remove the bolt at the bottom of the fork.  The cartridge doesn't want to come out on either fork.  We even tried the "slide hammer" technique of clamping the damper rod in a vise (aluminum jaws) and sliding the fork tube outwards.  Nothing!

My forks are almost like the pictured forks, but the caps do not screw on to the damper rod.

As you all point out, there is no need to remove the cartridge to simply change the seals, but I was hoping to see a port or hole or something that might perhaps be blocked.  I have re-torqued the bolts that hold the cartridges into the fork leg.

I rebuilt some WP forks on an ATK, and the cartridges filled with oil with about four or five strokes.

Still at a loss.

J

[brad black]

the 40mm non adj marzocchi as fitted to the m600 and 750 pre 2000 ish don't have a cartridge as such.  they have a damping block of some sort that is captive in the fork tube.  it is not removable without removing the lower section (axle mount piece) from the tube and then unrolling or machining off the rolled section.  everything about them is just cheap crap, even the chrome.  but only because that's all ducati was willing to pay for.

I send them out to get rechromed complete and a local company does the unrolling/re-rolling bit, so I've never actually seen what it is.

this is a really good example of people posting irrelevant rubbish in answer to specific questions.  I know people are just trying to help and this is the internet, but it really shits me.

anyway.  you could try lifting the outer tube up a fair way, being careful to not uncover the hole in the side, screw the cap on fully so the o-ring seals it and then push down hard and fast to try to force oil into the damping block.  some of the old 851 era ohlins need this done to start them bleeding, tho I've never had to do it to a marzocchi.  I guess you could just put your hand over the top of the tube to seal it too.

[BK_856er]

Shows you what I know!

BK

[memper]

support the fork by the lower section somehow.

slide the outer tube all the way down.

pour 400ml or so of oil into the tube.

slide the outer up and down a few times.

grab the end of the damping rod (I screw a tube onto it) and move it the full length of travel in each direction (pull up hard, push down easy) 15 or 20 times.

set oil level.

easy.

+1

[brad black]

Shows you what I know!

BK

as a side note: did yours have a plastic sleeve / spacer over the cartridge rod that fitted inside the spring?  they're the 43mm forks I was playing with in my air gap thing and rick at motocd said there should be a spring inner sleeve in them, but the one I had didn't have it.

[ducpainter]

<snip>

this is a really good example of people posting irrelevant rubbish in answer to specific questions.  I know people are just trying to help and this is the internet, but it really shits me.

Just what irrelevant rubbish are you referring to?

[brad black]

Like BK says, the cartridge assy is removable, but not serviceable on those forks.

that, for a start.

in his initial post he said they were 40mm marzocchi.  the above is simply not correct for those forks.  it's a specific question about a specific part with specific info given that you and bk ignored and told him completely the wrong thing.

[BK_856er]

that, for a start.

in his initial post he said they were 40mm marzocchi.  the above is simply not correct for those forks.  it's a specific question about a specific part with specific info given that you and bk ignored and told him completely the wrong thing.

No fair - I claim ignorance!

BK