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All things warp and some other stuff
Marzocchi All Mountain 1 Service and Tuning
Marzocchi All Mountain
As
Captain Barbosa said this page is "...more a guideline than a
rule"...
The All Mountain 1 fork used to be the top of the
line
It's air-coil sprung. Which is nice. If an
air seal ever blows, you can limp back home on the coil spring and the
pressures used in it are very low to keep stiction at a minimum. I'm not sure
if it's the Zoke seals getting tighter with pressure or the nature of the air
spring that makes the fork to feel "notchy" as air spring pressure
rises.
It is a 32mm stanchions fork, with a very sturdy, yet light crown. The overall
package is pretty light for the travel and intended use. It comes at around
2.3kg or like 5 pounds with a cut steerer for the 150-130mm version. The
110-130mm version should be a tad lighter as the lower assembly and cartridges
are shorter and surprisingly, not compatible with the 150mm sister.
The legs of the fork contain the following:
Left
Leg:
ETA/TAS Cartridge - The ETA is a lock-down device
with a 30mm "buffer" that gives you said travel even if the fork is
completely lockdown. It's the best climbing dedicated system, in my opinion.
It's simple to operate and in the way it's made. It is a simple rod with a piston with a one way valve that can be
activated by the corresponding knob on the crown of the fork and the
"buffer" travel is provided by a lower shaft at the bottom of the
cartridge with it's own spring and what appears to be a simple piston with
unknown function, independent of the ETA cartridge. The TAS is a simple
threaded shaft that threads to the main ETA cartridge (the lower ETA shaft, to
be specific) shaft winding up to 20mm travel adjustment. It's recommended by
Marzocchi to deflate the fork before adjustments are made, but in the practice,
it's well enough to compress the fork to release the shafts of the binding
pressure exerted by the springs. It's the bottom knob of this leg.
This Cartridge is the one affected by the oil
level but different oil weight would have little effect. In compression, it should not affect at all, but in rebound, the orifice may cause spiking if too heavy oils are used. However, I currently run a 10wt oil with no adverse effects on rebound.I'd expect ETA to creep up if light
oils are used, but I'm not quite sure as the one way valve gets completely shut, being the seals the only thing preventing the creep up. This
cartridge also contains the coil spring which is absolutely necessary to extend
the fork once the ETA is deactivated, so the fork could go back to full
extension.
This leg is "open bath". Meaning that
cartridge and bushing lubrication oil is the very same and it can act as a
bottom out control media. As the volume of the air chamber left between the oil
surface and reduces, the pressure increases and the resulting increase spring
rate can help the fork to avoid bottom out by effectively stiffening up by the
end of the travel. This is better than having a bottom out bumper that could
wear over time and having less (or none) harsh impacts on bottom out.
Here some pics of the ETA internals.
By warp2003 at 2007-03-03
By warp2003 at 2007-03-03
By warp2003 at 2007-03-03
By warp2003 at 2007-03-03
Right
Leg:
TST Cartridge - This is the heart of the fork. The
damping unit and contrary to Marzocchi tradition, this cartridge is completely
closed and does not share the lubrication oil with the rest of the leg. It's a
closed cartridge with rebound and compression separated pistons and a rubber
bladder to provide oil displacement compensation. On the rebound side the
piston is a simple fixed-size orifice with an adjustable bleed which provides
rebound damping adjustment (at the bottom of the leg).
The compression assembly - again, contrary to all previous Marzocchi custom for high end models - it's adjustable and it's a very simple variable (or better said, selectable) orifice size and a spring loaded blow-off washer.
TST seems to be not as speed sensitive and more prone to fading... and despite to what you could be lead to believe by the compression adjustment, it depends more on finding the right oil weight for your riding due to the fixed size orifice damping.
This leg is semi-bath. Meaning that the oil that lubricates the bushings, is not the same and it’s not in contact, with the damping oil. This is an advantage in the sense that the dirt collected by the lubricating oil will not reach the damping unit and will not affect damping. However, I've found that it can cause the fork not to feel as plush as a full open-bath one. Also, the upper bushing of the fork may get "unprotected" is the oil slides down from it.
Taking the AM ApartNow, following the Marzocchi tradition, working with the fork (exception made of the TST damper) is very simple.
Tools Needed:
12mm thin wall Socket (See Note 1)
21mm socket, chamferless, 6pt (or a quality crescent wrench)
10mm open end spanner
2.5mm Allen Wrench
Rubber bands, suitable o-ring
Old tyre tube
Note 1.- Marzocchi makes a specific tool for these foot nuts. The thin or ground wall socket is needed because the foot nut sits inside a recess in the lower casting which limits the grip of any other tool used.
1.- Remove all dials except for ETA, for now. Be careful with the one of the TST. A spring loaded ball is underneath and they are easy to lose. Keep them in a safe place, unless you want to have "infinite adjustment points" like my fork is.
2.- With ETA engaged, loosen up both foot nuts with either the Zoke tool or the 12mm socket. Oil will come out now, so don't forget to place a pan underneath the fork before loosing them up.
3.- Release ETA, remove the respective knob and with the crescent wrench or the 21mm chamferless socket, loosen top caps completely. The chamferless socket is needed because the flats on the topcaps are pretty shallow and the top cap material is very, soft. Not as bad as older Zoke forks, though. Drain ALL oil.
4.- Now you can separate the cartridges off the fork and separate both uppers and lowers too. More oil will come out. Cycle both ETA rods to remove all oil inside such cartridge. Check if the TAS assembly is properly tighten to the lower ETA cartridge.
5.- For AM1 - With the 12mm spanner, hold still the polished nut on the ETA cartridge and loosen the ETA top cap counterclockwise. Remove Spring and spacers. For other Marzocchi forks (MX Comp, Marathon, etc) loosen the red nut itself until it comes off the ETA main shaft and remove the spring and spacers. Note the order they were installed. Cycle the rod even more... more oil will come off, but hopefully little now, if you did the last steps correctly.
6.- Now clean everything. A lint-free rag (any 100% cotton tee-shirt remains will do) will suffice. You can go the long way and degrease it, but hey, you're gonna put oil back in again.
If you're just making an oil change, proceed to 7, if you're making a TST service and/or bleed, proceed to "a)"
a) Move all dials to the open position, so you don't loose reference out of it.
b) Now, with a small screwdriver remove the circlip between the main shaft and the top cap.
c) With the 10mm spanner hold the flats on the compression assembly and remove the top cap by turning it counterclockwise with the 21mm socket or crescent wrench.
d) Here the things get interesting. Marzocchi states you need another special tool. A soft clamp for the main body of the cartridge. You should use the soft clamp and a vice to hold the main cartridge body and then remove the main compression assembly with the 10mm spanner. I degreased the main body of the cartridge and held it with a old tyre tube in my hand, while I undid the compression assembly with the spanner. It was a PITA to make it come loose, but I finally got it.
e) Once the Compression Assembly is loose, use a turning action (like unscrewing it) to make it come off. Otherwise you can damage the seals with the threads on the main body.
f) Dump all old oil, or if you're simply bleeding, proceed to the next step.
g) With the rebound shaft all the way extended, refill with oil to the brim. Break any bubbles formed in the oil and cycle the rebound shaft a few times slowly, to get rid of any air behind the rebound piston.
f) Once the cartridge is full to the brim, put back on the compression assembly.
h) Now compress the rebound shaft until it shows 160mm to the red nut at the bottom and slide a tight rubber band or o-ring halfway down the bladder, so the oil gets trapped below it.
j) Extend the rebound rod and remove the compression assembly again. Now refill with oil to the very brim again.
k) Reinstall the Compression Assembly carefully so no air is trapped in and remove the o-ring/rubber bands.
l) Reassemble the whole cartridge in reverse order as stated before.
To verify you did things correctly, turn the TST knob to "Lock-out". It should lock out. If it doesn't lock out within the first 3/8" (10mm) of shaft travel, then you need to do the bleed (properly this time) again.
This is a video explaining how to bleed a TST Cartridge by Marzoccchi...
7.- Smear a little bit of some assembly lube grease (Rock N' Roll's Super Slick has worked wonders for me, but any decent seal shop may have some cheap and decent, seal quality grease) on the wipers and seals of the fork and now start the uppers into the lowers. Going even on both legs at the same time helps lots. Sink them to the bottom.
8.- Now put in cartridges and tighten foot nuts. Check proper torque at Marzocchi's homepage, but just snug will do. The seal is provided by an o-ring on the foot nut. NOTE: ETA Cartridge is preferable to have still with the spring not installed.
9.- Pour 40ml of oil on the TST leg.
10.- Pour oil into the ETA leg, while cycling the rod, to ensure the cartridge is being completely filled up. With the uppers completely into the lowers and the ETA shaft as low as possible into the cartridge, pour oil until you get between 45-55mm between the top of the crowns threads and the surface of the oil.
11.- Reassemble ETA cartridge. It takes some patience, but it can be done.
12.- With the TST Locked up, slide uppers up and tighten top caps. Again, snug is fine. Seal is provided by the o-ring underneath the lip of the top cap. The reason to have the TST locked out and having the sliders to come to the top caps and not the other way around, is to prevent the bladder to “swell” (it is an oil volume compensation device) and help it to go easier into the uppers.
13.- Reassemble knobs. Yo' done, bro!
AM Tuning!!!!
Now the interesting part of the job... How to make the AM1 to work perfect for YOU!!!
I've just left aside from the instructions the oil qualities and weights... Why? Because depending on what you're looking for, it'll be the fluid to use.
Stock oil for the whole fork is Golden Spectro 125/150 which is roughly equivalent to SAE 7.5wt.
For my weight and riding conditions... it was just not cutting it. It was not related to the quality of the oil itself as Spectro is a damn hell of a good oil to start with. But the fork was having some quirks that needed to work out.
First... On the Semi.Bath oil - either my local conditions are very hot or dry that the fork after a few miles being ridden, it felt notchy and with more stiction than desired. I traced it to the TST semi-bath lubrication. I'm using a 10wt oil in that leg and it still feels a bit notchy at times, but much better. I'll use a synthetic engine oil 20-W30 or something just more viscous so it stays more time at the upper bushing, and provides a smoother feel on the next oil change. My concern here is that the used oil would damage seals or the bladder. Synthetic engine oil has been used on other semibath forks with success, but I may stick to a heavy Fork Oil like 15wt or 20wt.
Second... Even with the thicker oil for semi-bath lubrication, it was feeling notchty. But this time it was not at the top of the travel as it is when it comes to stiction, but between large and small hits. My suspect was the fixed orifice damper. So, I went to 5wt lighter oil in the TST cartridge and it worked like a charm. Now the positions of the TST dial are useable and the fork stroke feels buttery smooth.
If you feel the fork to spike, go for lighter than stock oil. If you feel the knobs do nothing or go trhough quick to the travel in the first and second settings from full open on compression, go for heavier (10wt) oil.
I would mess up with the ETA oil volume to achieve full travel or more progression to the end of the travel. But I see little to none use on trying a different oil weight than stock.
Setting the fork Up...
Follow these steps on this very strict order.
1.- Set proper sag. AM's feel happy at around 25% sag. Especially when set at the minimum travel setting. Then, if you go to the max (or close to), the volume of the air chamber will expand and will get you closer to the 30% sag for more aggro riding.
2.- With the now classic "curb test", set the rebound so it bounces one time and without bucking you up. Then back off the adjusters one or two clicks, depending on your tastes.
3.- Tune out brake dive by using the second TST position from fully open. Please note that when working out brake dive, you also cancel some fork bobbing, but you lose small bump sensitivity and may sacrifice a bit of traction.
4.- Put a zip tie around one of the legs. Make sure you bottom the fork out (or come very close to it) on the biggest stuff you do on your usual trails. If you do, congrats! Your fork is set-up.
If you're not using all the travel, open the ETA topcap remove 5ml's of oil until a) You achieve the full travel or; b) your ETA does not engages. If you reach the point of not getting full travel AND ETA not engaging, reduce your preload a little and try again.
If you're bottoming the thing out, simple add 5ml's of oil until you just stop bottoming.
That's it for now... if you have more doubts, comments, clarifications, disclaimers or love declarations, please let me know. This is a work in progress. THANKS!
HSCV Conversion... Make your All Marathon S
This is a very straightforward procedure.
Get a donor fork, like a 2005 Z1 FR1 or FR2. Or get the cartridge straight from Marzocchi, complete with footnuts, topcap and dial.
Now just pull out the TST and insert the HSCV. Done.
There are a couple things to watch at, though.
In order to tighten the footnut, start it by hand and befor putting any oil in it, close the topcap and inflate to something like 20psi. Now you can do the footnut.
The only other method I know to tighten it is to use an impact wrench.... but I don't know many people who has one at home.
Some pics to illustrate...
Donor...
Footnuts are equal...
Footnuts are interchangeable...
Topcaps have the same thread pitch, but they attach in a different way to the cartridge.
Both Cartridges are of comparable length, but the TST can give out like 170mm of travel while the HSCV "only" like 160mm
End result...
You gotta be out of your mind... But just in case you'd try to do it the other way around, and want to put a TST on a HSCV bike, you just can't. There's a ring in the Z1's stanchion...
Caveats when Servicing Marzocchis...
Marzoccchi often makes subtle changes from model to model and year to year that can render perfectly useable parts, useless on other forks.
For instance, you can't drop a TST catridge on a Z1 from 2005 for the reason stated above.
Way more odd, is the fact that you can't actually use 2006 All Mountain 1 lowers on 2005 models... They just don't go all the way up. There's a spacer at the bottom of the lowers casting, that prevents you from it. I'd like to have a 2006 one at hand to check out if the stanchion are same length, I think they do.
Note the Z1 does not have this spacer...
