More on Ceriani 38mm forks.

[Lyndoneil]

Well, that was illuminating, I learned I need some better circlip pliers.
Other that that I'm little wiser as to why the front forks seem to be dubious.
Both fork springs measure 470mm, the pistons although a little scoured both move freely.
The oil quantity was a little low at about 180cc, although it was difficult to measure as nothing came out of the drain hole, so I thought there couldn't be any inside, until I undid the bottom allen bolt, then it flooded out everwhere.
There is some sludge in the bottom of the lower stanchion and the rightside little mid spring looks very tired but is most likely unobtainable.
Other than that, without the measurements for checking wear on the internals, I'm foxed.
Maybe it just had the wrong grade oil in it.

 

[TeddyG]

So what's the problem w the forks- too harsh? Try mixing 10 and 5 wt and that should soften them up. Some have had good results installing the gold emmulators, and there's also progressive fork spring kits like this one:

 

[Vince]

All modern forks run replaceable bushes; Maz and Cer don't, so there is inherently a lot of Stickson. Nature of the beast. 2 easy ways to reduce that, some really clever types have fitted bushes, but it's a NASA-grade job. So, back to the easy ways. Race Tech recommends getting the lower tubes Hard Anodised, the other way, or you can do both is SKF green oil seals. Their blood brilliant, but expensive at 3 times the typical fork seals. The first time I saw this video, I immediately bought a set. It's not BS, well worth the cost.

 

[pf1]

Were they assembled in the correct order? There are numerous incorrect examples of how to assemble the components even on this forum. The correct diagram is shown on Laverdamania.

 

[Jo]

In 2019, before my trip to Breganze, I filled my fork with 380cm³ of oil, which was obviously far too much. I'd found two different recommendations at that time and probably thought more was better. The fork was rock hard, and in Breganze, I saw that it was pressing out oil:

Oil under the fork - Breganze 2019

Back home, I disassembled the fork again and filled it with fresh 10W oil (mixed with HKS fork slide improver) and a 20cm air cushion (measured without the spring and fully compressed). From my records this is 272cm² / side. Works brillant now.

 

[Lyndoneil]

So what's the problem w the forks- too harsh? Try mixing 10 and 5 wt and that should soften them up. Some have had good results installing the gold emmulators, and there's also progressive fork spring kits like this one:

Hi TeddyG
Yes, too harsh, I've the same forks on a Ducati 860, which work excellently, so I know they can be better.
It had been filled with 10wt oil.

 

[piranha-bro2]

As mentioned on here previously, I've recently rebuilt a pair of Ceris - one leg had the rebound damper system in arse about - that made for a hard ride. It's very easy for punters to get it wrong.

 

[Lyndoneil]

As mentioned on here previously, I've recently rebuilt a pair of Ceris - one leg had the rebound damper system in arse about - that made for a hard ride. It's very easy for punters to get it wrong.

 

[Lyndoneil]

I will check out the order of the parts against each other and how its been put together against the exploded part diagrams in my Ducati 860 and Laverda 750 parts books, apparently the green book is incorrect, although at present I can't see where.
I'll measure the parts against each other, then have to decide where I go from there. new seals, springs emulators?
I'd love to just send the forks to Maxton, but at the moment with the value of classic bike falling so steeply, Im reluctant to spend 20% of the bikes value on just forks.

 

[The Sock]

I'd love to just send the forks to Maxton, but at the moment with the value of classic bike falling so steeply, Im reluctant to spend 20% of the bikes value on just forks.

Rather depends on whether you want a character filled bike that's fun to ride, or an armchair to sit in while watching your investments pay off, in Sterling.
The problem is, the government will claw a percentage of all your financial gains.
They haven't figured out how to tax fun, yet.

 

[Lyndoneil]

Rather depends on whether you want a character filled bike that's fun to ride, or an armchair to sit in while watching your investments pay off, in Sterling.
The problem is, the government will claw a percentage of all your financial gains.
They haven't figured out how to tax fun, yet.

View attachment 101164

It's still an option I have not ruled out, but with this lot to look after I have to be cautious.

 

[Lyndoneil]

Two exploded diagrams, one from my Laverda sf parts book, one from my Ducati parts book. Same forks. They're different.
Which is correct?
The Laverda, (right) shows the small spring seat and spring at the bottom, The Ducati (left) has the spring seat and spring between the valve rings/diaphragms (depending on which version of bastardised English you prefer.)
I'm assuming the Ducati pic is correct.

 

[pf1]

suspensionsgb

suspension

uk.laverdamania.net

 

[Lyndoneil]

There isn't an exploded diagram of the Ceriani forks on Laverdamania, only the Marzocchi, but the info is useful nethertheless, from the measurements detailed for the length of the slider which is 570mm on mine means the spring length should be 505mm, if that's correct it suggests my springs might be slightly tired at 470mm.
So maybe I should look into them and maybe the SKF seals, as mine are fairly tight and binding without any other parts installed

 

[pf1]

Thread 'ceriani damper assembly'

Jan 14, 2013

I am just trying to reassemble the damper rod and assembly in my Ceriani front fork and have placed the components onto the damper rod the same as the layout appears in the green book but cannot bet the assembly to fit into the recess in the bottom of the fork what am I doing wrong have a look at the pic of the assembly???????

• mauricejota7604
• Replies: 14
• Forum: Technical

 

[Tippie]

Two exploded diagrams, one from my Laverda sf parts book, one from my Ducati parts book. Same forks. They're different.
Which is correct?
The Laverda, (right) shows the small spring seat and spring at the bottom, The Ducati (left) has the spring seat and spring between the valve rings/diaphragms (depending on which version of bastardised English you prefer.)
I'm assuming the Ducati pic is correct.

Pic ending in 58 is correct. If you add oil and move the slider through it's travel you will easily see if the valve is upside down the damping will be super hard on compression as the flapper valve shuts off the holes in the valve washer in the wrong direction. It is this brass valve that can be worn out with big clearance to the damper rod or worn/bent on it's flat towards the valving washer/disc. As for oil quantity, a triple fork stanchion is much longer and will have more oil capacity. My factory SF2 manual specifies 200cm3 of oil, which covers the damper valve by about 2 cm fully extended. On all conventional damper rod forks I have serviced, the factory spec ends up at the same effect of couple of cm over the valving fully extended. Adding more oil than this is effectively increasing air spring effect as there is less volume of air being compressed as the forks move down, it will not have any affect on the damping, and adds a bit more volume of oil to be contaminated over time if it doesn't get changed. I prefer to let the spring do the springing.

 

[Lyndoneil]

Thought I better add to what I have found/achieved with the Ceriani fork rebuild.
When I first stripped the forks I found the springs had compressed to 473mm length from an original new length of app 505mm, if the info online is correct.
Initially the pistons on the damper rod seemed free, until I tried to reassemble, where one piston wouldn't slide back into the slider, the same with a couple of the valves on one stack.
Unfortunately by this time, despite warnings and every effort not to get the parts mixed up, I had.
So I started from scratch, married each component into a slider that would except the part and in the absence of a lathe, the parts that wouldn't were treated to a bit of a rub with 600 grit wet and dry until they did.
The old seals were a brief problem, there being only one either side, approximately 10mm deep and totally seized solid and being fearful of breaking the edge of the stanchions at the top, my Aldi copy Dremel
tool came to the rescue and I cut the old seal out with a tiny disc, the new Ariete fork seals supplied by Keith Nairn, 2 per fork leg, fitted comparatively easily
The new progressive springs from Keith measure app 462mm.
So as per online advice I made up 2 sets of spacers using some solid plastic rod I have and steel washers either side to a combined length of 40mm, and the new springs installed with the tighter windings at the top.
Now the forks are temporarily reassembled and feel nicely springy, however, I've not added the oil yet, as its New year's day and everywhere is shut. I'm intending to put 10wt in, 200cc and see how that works.
I can't refit the forks yet anyway, as the fork shroud/headlight brackets are off being re-chromed whilst it was all apart.