Ducati.ms - The Ultimate Ducati Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter #1 (Edited)
My SP Blew a fork seal.

Get seal...not from Ducati
A 50mm seal installer. Some people use home made pvc ones. Hey, the driver is cheap compared to redoing the job!
This is a nice touch or something similar.
Loosen the fork caps after loosening the top triple clamp. Remove legs

You'll need to buy a 4mm pin wrench This one is inexpensive but will require a little filing of the pins as they are slightly to big!
You'll need to find a way to firmly hold the fork leg without damaging it. More on that later.
Unscrew the top cap. Pull down on the spring tube so you can slide a 17mm wrench on cutout of spring holder shaft. Hold wrench and with pin wrench and 19 mm socket remove the to cap. Be careful not to bottom the preload to hard, it can jam = $$. Set spring and plastic seat aside. Drain oil.
Place leg in holder and remove 10mm allen from bottom of leg. Screw the bolt back in slightly and tap it with a punch or long allen to separate the cartridge from the leg. Pull out the cartridge set aside.
Pry off scrapper seal. Reach into leg + pop out spring retainer.
Now comes the fun part..yank the fork leg as hard as you (like a slide hammer) can and the seal and the leg will come apart.
When sliding the new seals on it's a good idea to wrap the top of the tube with thin packing tape so the edges are not an issue.
Here's a very good thing to check.
Take the cartridge and run the shaft through it's stoke. Is it smooth or does it make noise and have dead spots in the damping?
One of mine did. If that is the case you will have to bleed the cartridge. This also brings up an interesting observation. It's pretty much useless to change the fork weight oil unless you're going to empty out the cartridge too. It's sealed so any change won't make into the cartridge. The fork oil is actually only for lubrication and as a progressive air spring adjustment.
To bleed / change the cartridge oil you'll need to remove a tiny 4 mm Allen plug at the bottom of the cartridge. Be patient and tap the cartridge to get the air bubbles out. Move the shaft in and out slowly to help rid the air. You can take the bottom of the cartridge off to fill faster but I don't recommend it. It's on there very tight.
Reassembly as they say, is reverse of disassembly.
Have fun!
 

·
Registered
Joined
·
946 Posts
Good info. Took me a few minutes to find that plug at the bottom of the cartridge! How are your black stanchions wearing? Got any streaking, shiny spots, rock chips?

For bleeding the cartridge, it's very difficult to get all the air out because of how the bladder covers the orifices. There is also a minimum volume of oil required to prevent the bladder from plugging the orifices. A pretty lame design from a maintenance perspective. I was able to wrap tape around the bladder where the orifices are to get more oil in. Did you take the cartridge apart? I never got around to making a tool.


On re-assembly, this stuff is pretty sweet: Slickoleum Grease

I used Spectro 7.5wt oil in the cartridge. Very similar to the stock fluid. Ever so slightly thinner, which helped with the high speed harshness.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #5
I looked everywhere for info on this to no avail. Yeah, that plug was key! Funny thing was the way I found it was by disassembling the cartridge first! I have some shiny wear on the stanchions, not to bad for 32K. From what I gather the SAE wt. spec is not to reliable. I used Ohlins fork oil fluid #5. Viscosity: 23cST @40deg. C. Does the oil you use have a viscosity index?
Next is replacing the front brake line......tank & airbox off....ugh. Three years of rallying turned the line into a crushed steering stop! Thinking of going for an RCS17 M/C while I'm at it.

FORZA
 

·
Registered
Joined
·
946 Posts
I looked everywhere for info on this to no avail. Yeah, that plug was key! Funny thing was the way I found it was by disassembling the cartridge first! I have some shiny wear on the stanchions, not to bad for 32K. From what I gather the SAE wt. spec is not to reliable. I used Ohlins fork oil fluid #5. Viscosity: 23cST @40deg. C. Does the oil you use have a viscosity index?
Next is replacing the front brake line......tank & airbox off....ugh. Three years of rallying turned the line into a crushed steering stop! Thinking of going for an RCS17 M/C while I'm at it.

FORZA
Here's what I know: http://www.ducati.ms/forums/92-hypermotard/324673-hyper-sp-821-fork-shock.html

The oil I used: "Light" 7.5wt has a viscosity of 26cSt at 40C and VI of 150. http://spectro-oils.com/wp-content/techsheets/Golden Cartridge Fork.pdf

So about getting the cartridge apart... I have a few questions. Where exactly are the threads, on the top near the o-ring seal or on the bottom? Did you have a heat it up? What tool did you use? Are they normal right-hand threads? I have thought about measuring and changing the shim stack to slightly reduce high speed compression damping on the fork.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #7 (Edited)
Oooooooh, now you're gettin' fancy! Ummm, I went crazy trying to take the top cap off but in trying it's the bottom that came loose. The hard part is how to hold the cartridge while unscrewing the bottom. It uses normal threads. Here's how I held the thing. I thought about heating too but went this way; it's not pretty but it worked. Get some emery cloth, rip a strip the width of the indented step on the bottom. Wrap tightly with grit side in. Clamp with curved vise grip and use pin wrench......but be prepared it is very tight. There's no gut's down there so you're safe. BTW with the bottom off it makes filing and bleeding much easier, just finish thru the 4 mm plug.
Re; viscosity, yes the Ohlins is thinner, which is why I used it.
Did any of your cartridges need bleeding (before you dissembled)?
I used to re-valve Koni's for different spring rates but Koni would sell the shim packs with specific specs attached to them. I wouldn't know where to begin with the forks. It would be a lot of work to find out you were wrong! I just gained 15 pounds and that fixed it!
BTW those pictures of the Panigale cartridges really threw me in into thinking it was the top that came apart. The Hyper outer tube looks quite different.
As another aside, these forks were replaced. I was victim of that early batch that had zero dampening.
 

·
Registered
Joined
·
946 Posts
Interesting. I was thinking of making a special pin wrench socket thing so I could hold each end, and then twist the entire cartridge in an unscrewing motion.

My cartridges didn't need bleeding. Was there oil in the lower air chamber portion? You might have a leak.

My friend is pretty versed in suspension tuning, having revalved many forks of different makes. I would certainly get his help when/if I tackle it during the next oil change.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #10
OK, I gave up!

I tried everything. Sometimes what worked was a disadvantage to some other aspect. Broke down and put a set of Andreani cartridges on. As far as I'm concerned, the best thing you can say about suspension is when it doesn't call attention to itself.............done!

BTW the rebound leg of the Marzocchi was a quarter full of air as was the compression I took apart a few months ago. I don't get it, doesn't Marzocchi know how to bleed their own cartridges?
 

·
Registered
Joined
·
946 Posts
I tried everything. Sometimes what worked was a disadvantage to some other aspect. Broke down and put a set of Andreani cartridges on. As far as I'm concerned, the best thing you can say about suspension is when it doesn't call attention to itself.............done!

BTW the rebound leg of the Marzocchi was a quarter full of air as was the compression I took apart a few months ago. I don't get it, doesn't Marzocchi know how to bleed their own cartridges?
How does the Andreani compare to the marzocchi? You're one of the few to be able to give a comparison.
 

·
Registered
Joined
·
95 Posts
Discussion Starter #12
How does the Andreani compare to the marzocchi? You're one of the few to be able to give a comparison.
Marzocchi's are schizophrenic. I think a lot depends where in the stroke you are. Andreani just do the job. They are not sealed/bladdered so we'll see if cavitation becomes an issue. I rode a 2018 with the Ohlins today...........yeah, it's the way to go. Love the 939 motor.......... so smooth and torquey.

Going to France October for 7 day rallye I'll let you know how the Andreani do.
 

·
Registered
Joined
·
946 Posts
Marzocchi's are schizophrenic. I think a lot depends where in the stroke you are. Andreani just do the job. They are not sealed/bladdered so we'll see if cavitation becomes an issue. I rode a 2018 with the Ohlins today...........yeah, it's the way to go. Love the 939 motor.......... so smooth and torquey.

Going to France October for 7 day rallye I'll let you know how the Andreani do.
Ah yes... I wondered how the Ohlins on the 939 is.

Surprisingly enough I'm happy with my Marzocchi now - got it dialed in just right and it handles well. Still has somewhat poor sharp-edge compliance but is well controlled.

Let us know how it goes :)
 

·
Registered
Joined
·
95 Posts
Discussion Starter #14
Extended length?

OK I have a question about the Marzocchi forks. Since installing the Andreani and setting the sag, I've noticed that I have a lot more trouble reaching the ground and it looks like the travel doesn't reach as far down the fork as before. Can someone give me a measurement of the Marzocchi fully extended length. Say, from the bottom of the fork tube to the top of the axle casting?
Here's what I have now
http://www.ducati.ms/forums/attachment.php?attachmentid=911066&thumb=1 220mm
 

Attachments

·
Registered
Joined
·
95 Posts
Discussion Starter #16
Yeah, so the Andreani are a little different. The fork extends further than stock and the bottom travel is a 20mm less. Hmm.......
 
1 - 16 of 16 Posts
Top