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
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
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.
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
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
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
(http://i44.tinypic.com/jk8781.jpg)
Quote from: motodoc on January 13, 2014, 08:56:54 AM
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.
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
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.
Shows you what I know!
BK
Quote from: brad black on January 13, 2014, 04:30:29 AM
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
Quote from: BK_856er on January 13, 2014, 04:38:26 PM
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.
Quote from: brad black on January 13, 2014, 02:50:27 PM
<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?
Quote from: ducpainter on January 13, 2014, 01:05:27 PM
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.
Quote from: brad black on January 13, 2014, 07:32:40 PM
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
Quote from: brad black on January 13, 2014, 05:04:16 PM
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.
Nope - all the parts that came out are shown in the pic, except for the large c-clip retainers. Still got 'em in a box. '07 M695.
BK
Quote from: brad black on January 13, 2014, 07:32:40 PM
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.
I was wrong.
Go ahead...hate me.
Brad:
THANK YOU! THANK YOU! THANK YOU! I thought I was REALLY screwing up and/or missing something given the advice I got. To others who offered advice, thank you for your efforts. We just can't know about every make and model of components on machinery. The forks I have are, as Brad pointed out, just cheap. As I pointed out, I'm doing the work at a machine shop. The guy works magic with engines. As a side note, he asked me if my Monster was jerky at low speeds. YES! His response was something like it is because it is basically two separate engines trying to operate independently. He said that Ducati lines up the timing marks on the cam "gears", but what really needs to be done is to degree-in the cams. I'v seen him do this on other high-performance engines, usually singles. Once I sort out the obvious things (e.g. forks) on my bike, I am going to degree-in the cams.
To the matter at hand. Brad: interesting that you should suggest putting the cap on the outer fork tube and pushing down rapidly. The Race Tech book makes that suggestion by using a hand to cover the fork tube. I think I'll try a modification of lifting up the outer tube, filling the inner tube to the top with oil, then exerting pressure using a long clamp or tie down, then come back in an hour or so. My one concern is if I increase pressure on the oil to force it into the cartridge, will the air be able to move out of the cartridge from (what I would presume) a compartment with lower pressure into a compartment with higher pressure. Perhaps that's why short, rapid compressions are successful.
Either way, thank you for the suggestion!
By the way, when I bought the bike, I had some work done at a shop in N. California. New tires, timing belts, adjust valves, new chain. A lot of stuff worth $1600 (about half what I paid for the bike). The seat lock is missing as well, so I went to order it from the shop. The mechanic let me know the Ducati no longer supplies the seat lock for such an "old" bike. Then he asked if he could do anything else for me, so I asked for tips on bleeding the air out of the cartridges on the Marzocchis. NO RESPONSE! I didn't know these guys from Adam. I went there on a recommendation from my buddy who has a Monster, spent $1600 and he can't give me any suggestions. I understand the idea of being in business is to make money, but I'm not driving three hours so they can bleed the air out my cartridges. I'll try a local mechanic here in Chico or go to Sacramento which is "only" 90 miles away before I drive three hours to Marin county (and pay $200 for an hour of labor). I was able to get a seat lock off eBay for only $30 in about 10 minutes (a new one was going to be $120).
I apologize for rambling.
Jack
With regards to being jerky at low speeds, degreeing cams will help smooth things out, but changing your gearing will do more to help eliminate the 'snatchiness' at low rpms IMO. Ducatis are geared pretty tall from the factory for emissions/noise purposes.
Some people install a smaller (14T) front sprocket. I prefer putting more teeth in the rear.
You might check gearingcommander.com for a spreadsheet on gearing changes and their effect on top speed.
ducpainter: Thanks!
Lastly, regarding the forks: Is it possible that the cartridges ARE indeed filling, but the compression dampening is virtually non-existent? When I do fill the fork tube(s), air does bubble out of the cartridges. It is just when I start stroking the dampening rod, there is almost no resistance during the compression stroke until about an inch from the bottom of the stroke. Then on rebound there is dampening. There is a lot of dampening at the bottom, but if I push the dampening rod about halfway down, then pull up there is definitely resistance, just not a whole lot. It is the downward part of the stroke that has very little, if any, dampening.
I've already started to look for forks on eBay. I'd prefer something that will "bolt on", but in my experience, when we start mixing parts from various machines there are always modifications to make.
I'll put the seals in and live with the forks I have until I can swing another pair or REAL cartridge forks.
Thanks to all again!
Jack
Quote from: motodoc on January 15, 2014, 03:01:06 PM
ducpainter: Thanks!
Lastly, regarding the forks: Is it possible that the cartridges ARE indeed filling, but the compression dampening is virtually non-existent? When I do fill the fork tube(s), air does bubble out of the cartridges. It is just when I start stroking the dampening rod, there is almost no resistance during the compression stroke until about an inch from the bottom of the stroke. Then on rebound there is dampening. There is a lot of dampening at the bottom, but if I push the dampening rod about halfway down, then pull up there is definitely resistance, just not a whole lot. It is the downward part of the stroke that has very little, if any, dampening.
I've already started to look for forks on eBay. I'd prefer something that will "bolt on", but in my experience, when we start mixing parts from various machines there are always modifications to make.
I'll put the seals in and live with the forks I have until I can swing another pair or REAL cartridge forks.
Thanks to all again!
Jack
If you are in the US, either think about re-springing them or trying to get S4R/S2R1K ones AND having them set for you . . . you might also want to try a heavier oil, 10W if you need them to be more 'stiff' . . . being there, done it . . . got re-sprung ones with some RaceTech internals also heard good comments from a few friends that are using Hyperpro
Quote from: motodoc on January 15, 2014, 03:01:06 PM
ducpainter: Thanks!
Lastly, regarding the forks: Is it possible that the cartridges ARE indeed filling, but the compression dampening is virtually non-existent? When I do fill the fork tube(s), air does bubble out of the cartridges. It is just when I start stroking the dampening rod, there is almost no resistance during the compression stroke until about an inch from the bottom of the stroke. Then on rebound there is dampening. There is a lot of dampening at the bottom, but if I push the dampening rod about halfway down, then pull up there is definitely resistance, just not a whole lot. It is the downward part of the stroke that has very little, if any, dampening.
I've already started to look for forks on eBay. I'd prefer something that will "bolt on", but in my experience, when we start mixing parts from various machines there are always modifications to make.
I'll put the seals in and live with the forks I have until I can swing another pair or REAL cartridge forks.
Thanks to all again!
Jack
Do both legs behave the same?
I know some later bikes have compression damping in one leg and rebound in the other, but I didn't think any Monsters of that vintage were like that.
Both legs respond the same way. Just for "kicks" I disassembled the second fork leg to see if it was set up the same way. Sure enough. hardly any dampening until about an inch from bottoming out. Just for kicks AGAIN, I filled up the second leg with fresh oil. Got the bubbling, and the dampening rod behaved in the same manner.
Thanks for the advice on heavier oil! That will be my "cheap fix" until I can get some forks. Thank you also on the suggestions on what type/model to look for.
School starts Tuesday. Friday is a faculty meeting. I think tomorrow I'll "screw around" and put my Monster back together.
Thanks again!
J
That sounds about right. I have a '99 M750 with the Marzoochis. Both legs identical. I went to heavier oil in mine. It helps, but they're still not Showas or Ohlins. I shimmed for a little more preload & also dropped heavier springs in while I had them apart.
JM