USD fork question- 1999 Ducati Monster M750 with Marzocchi forks

[TonyB]

The front suspension on my Monster is pretty appalling. It dives heavily under brakes and bounces back way too quick. There is also a decent CLUNK coming from one of the forks... I think... it could be the brakes... The bike really needs some decent forks- the Marzocchi's on these things are well known for being shite- however a distinct lack of funds means that a temporary fix must be found.

So anyway, I decided to pull the things to bits to see whats going on, and I have stuck what I assume is a problem, (never having messed around with suspension I'm not entirely sure:wacko:)

They came apart easily enough. I did the left one first, undid the cap and the bolt at the bottom, compressed the spring, removed the C-washers so the cap, spacer and spring would come out. Slid the staunchion completely out and was left with the lower leg with the top of the damper rod(?) sticking out.

Now at this point I would assume that the damper rod and damper should just pull out of the bottom fork leg, because I undid the allen bolt at the bottom of the leg. Nope. There is a (maybe) 5mm threaded hole in the side of the fork leg. I thought maybe this has a grub screw which is clamping the damper in place. Nope. The hole be empty.

So I decide to do the right leg. When I go to undo the allen bolt at the bottom of the fork leg, it lets go with a decent "crack" like the first one did, but then the entire damper starts spinning inside the fork leg. So I find a long 5mm screw and use it in the 5mm threaded hole described above to clamp the damper. This works, and when the allen bolt is removed and the 5mm screw is slackened way off, I expect the damper assembly to slide out. Nope.

SO. My question is:
Is the damper supposed to come out after I've done the above steps, or is there something I'm missing? Do I need 'special tool xyz' to reach down inside the fork leg and actually unscrew it?

[TonyB]

55 Views and no answers??:wacko: Come on, somebody must know how to get this thing out!

More questions: Is it possible to have an upside down fork that doesnt use a cartridge? More like an inverted old style fork? I have no idea- please enlighten me.

[Cajun]

nothing in ducati service manuals?

[TonyB]

Probably not. The parts manuals all have the Showa fork- as I understand it, the bike was supposed to have Showa's, but quite a few got Marzocchis.

[Pixie]

I was going to post this last night,but it may not be the correct thing to do.

Screw the cartridge bolt partially back into the bottom of the fork and gently tap it with a drift to see if the cartridge moves

[Cajun]

do you know what other moster models had the marzocchis? maybe get a 900 manual or simlar?

[TonyB]

I was going to post this last night,but it may not be the correct thing to do.

Screw the cartridge bolt partially back into the bottom of the fork and gently tap it with a drift to see if the cartridge moves Well I got sick of waiting for the great fount of knowledge that is KB to give me an answer, so with it now being Monday I was able to ring 'a suspension guy' and ask him what to do. He suggested doing exactly that... gently.

[TonyB]

do you know what other moster models had the marzocchis? maybe get a 900 manual or simlar?
Good point, I'll give it a go.

[Robert Taylor]

Well I got sick of waiting for the great fount of knowledge that is KB to give me an answer, so with it now being Monday I was able to ring 'a suspension guy' and ask him what to do. He suggested doing exactly that... gently.

Do bear in mind that if you do recieve a good reply from say a specialist it is invariably done in ones own time and out of goodwill. As a number of us have very heavy workloads we will offer the benefit of any knowledge we may have with such problems, but as time permits. Before the days of the internet you may have had to make a phone call anyway and still often need to if you want more immediate answers.
Sometimes the lockbolts have a thread locking agent and in the absence of any form of cartridge holder the proverbial tap or judicious use of a heat gun followed by very careful manipulation by a good quality high performance 1/2'' drive air impact gun will often do the trick.
But frankly, once you pull those ''cartridges'' out you will be horribly dissappointed, they are basically a sealed unit and if you do get them apart they are little better than checkplates. Unfortunately, if you want a solution that actually works properly ( as a fluid dynamics enginner would design it rather than an accountant ) it would very much be a dollar exercise. And frankly there is nothing that will bolt straight in without some creative machining and adaptation etc.
The ''old wives tale'' of ''just put in some heavier oil'' doesnt really cut the mustard either. It will make little appreciable difference to the high speed rebound damping and will make low speed damping lazy and harsh.

[TonyB]

Do bear in mind that if you do recieve a good reply from say a specialist it is invariably done in ones own time and out of goodwill. As a number of us have very heavy workloads we will offer the benefit of any knowledge we may have with such problems, but as time permits. Before the days of the internet you may have had to make a phone call anyway and still often need to if you want more immediate answers.. Sorry, I was more taking the piss than directing it your good self or any of the other knowledgable suspension types on KB. It seems that KB is definitely more 'social' than 'technical' these days. Once upon a time I would have gotten some good (well, well meaning anyway) answers quickly...



But frankly, once you pull those ''cartridges'' out you will be horribly dissappointed, they are basically a sealed unit and if you do get them apart they are little better than checkplates. Unfortunately, if you want a solution that actually works properly ( as a fluid dynamics enginner would design it rather than an accountant ) it would very much be a dollar exercise. And frankly there is nothing that will bolt straight in without some creative machining and adaptation etc.
The ''old wives tale'' of ''just put in some heavier oil'' doesnt really cut the mustard either. It will make little appreciable difference to the high speed rebound damping and will make low speed damping lazy and harsh. My main reaon for pulling them out is to ensure that all the bits are actually there...seriously. I have recently seen several tales on line where people with Ducati's with clunking Marzocchi forks have had them pulled apart only to find that there are parts missing and the parts that ARE there aren't what they are supposed to be. I'll have a quick go at getting them out and if they wont budge I guess theres no point in forcing the issue.

Unfortunately my only option at the moment is to go with the old wives tale, though I think the real cause is that one leg had less oil than it should.

[Sketchy_Racer]

Sorry, I was more taking the piss than directing it your good self or any of the other knowledgable suspension types on KB. It seems that KB is definitely more 'social' than 'technical' these days. Once upon a time I would have gotten some good (well, well meaning anyway) answers quickly...


I was contemplating replying, suggesting what Pixie had, but was afriad of getting a flaming from real peoples in the know.

[Robert Taylor]

Sorry, I was more taking the piss than directing it your good self or any of the other knowledgable suspension types on KB. It seems that KB is definitely more 'social' than 'technical' these days. Once upon a time I would have gotten some good (well, well meaning anyway) answers quickly...


My main reaon for pulling them out is to ensure that all the bits are actually there...seriously. I have recently seen several tales on line where people with Ducati's with clunking Marzocchi forks have had them pulled apart only to find that there are parts missing and the parts that ARE there aren't what they are supposed to be. I'll have a quick go at getting them out and if they wont budge I guess theres no point in forcing the issue.

Unfortunately my only option at the moment is to go with the old wives tale, though I think the real cause is that one leg had less oil than it should.

No worries, it will be interesting to know if you find anything irregular. I have owned several Italian cars, love them but hate them at the same time.

[Taz]

My 900ss FE was the opposite. The fork halves were quite hard to pull apart but the cartridges came out easy..... But it has the showa's on.

[doc]

Sorry, I was more taking the piss than directing it your good self or any of the other knowledgable suspension types on KB. It seems that KB is definitely more 'social' than 'technical' these days.

I know how you feel
I have an electrical problem with one of my bikes. I asked on a internet forum which I belong about it, waste of time . However if I asked which cleaning products to use on the wheels. ...... but I found the answer eventually Google is your friend

[JD Racing]

Unfortunately, those forks don't come apart, there are some versions that do but you've struck out unlucky, the only safe thing you can do is buy a set of Showa's. I've only seen one set of Marzocchi's of that era and they could be stripped but I do know there are a lot that you can't.

Marzocchi forks are a pain, Cagiva Raptors have a sealed cartridge that you can't strip and their bush system is ridiculous.

[skidMark]

It's only good if it has USD's.

[Taz]

They do have USD's ya dick. A good set of conventional forks work just as well on the road.