Marzocchi SHIVER DC User manual

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GUIDE ASSEMBLY
The guide assembly for the stanchions is installed on the slider top
in all models (SHIVER models excluded). The tube is guided inside
the slider by a pilot bushing (1) with an upper bearing support.
Being the pilot bushing very large (92 mm), it offers a wide guiding
surface into the slider for the stanchion tube, so that the fork is very
stiff.
The pilot bushing consists of an outer copper support and an inner
anti-friction coating. As this coating is very thin, maximum care must
be paid not to damage it when disassembling the slider, otherwise
fork stiffness and performance might decrease.
SHIVER complies with M ARZOCCHI diagram for cross-country forks.
SHIVER DC: stanchions are guided into the outer slider by two
bushes (A) with a spacer (B) in between.
SHIVER SC: stanchions are guided onto the outer slider by a bush
(C), fitted on the stanchion and a bush (D) fitted on the slider.
Bushes are made of copper and are internally coated with anti-
friction material, which is in contact with the stanchion tube. To
replace them, remove the bushes from slider or stanchion, complete
with plastic spacer, if present.
A washer (2) working as a pilot bushing stopper and seal ring
support is on the pilot bushing.
SHIVER SC
SHIVER DC
2
1
A
B
A
2
C
D
2

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SEAL ASSEMBLY
A special seal ring (3) ensures proper hydraulic and pneumatic
sealing (the latter for air-operated forks) of the slider with respect to
its stanchion.
M ARZOCCHI has manufactured a special sectioned seal ring for
improving the efficiency of this part.
If sections are compared one with the other, it can be noted that the
special inner shoulder tends to become tighter on the tube, thus
increasing sealing, when the oil/air pressure pushes from the inside
to the outside of the M ARZOCCHI ring.
In the COMMERCIAL type, this push tends to widen the inner lip,
thus worsening ring sealing.
The seal ring is kept into its seat by a round circlip (4) with three
openings for easy removal from the slider.
The slider also has a dust ring (5) to prevent foreign bodies such
as dust, mud, water and so on, from getting in touch with the seal
ring (3).
This part is very important as it keeps inner parts safe and therefore
ensures proper suspension performance. It is therefore of major
importance that this part is kept in perfect working conditions.
Clean the area under the dust seal at regular intervals to avoid dust
and/or mud deposit onto the seal ring.
Seal ring
MARZOCCHI COMMERCIAL
5
4
3

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STANCHIONS
Stanchions are made of anodized “EASTON” aluminum or, in
some cheaper models, of aluminum alloy.
Stanchions are anodized for hardened outer surface and smoother
sliding.
Stanchion tube thickness may vary according to the fork structure
and features.
IMPORTANT !
For smooth operation of the stanchions, clean them at regular
intervals.

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STEER TUBE/CROWN/STANCHION ASSEMBLY
“EASTON” aluminium, aluminium steer tube with variable thick-
ness or steel steer tube.
It is forced onto the yoke and then cut according to the frame size.
“BAM” aluminium alloy crown, which is later CNC-machined at the
leg and steer tube seats.
Some models have two large holes for lighter structure.
For proper mating of the stanchions, their seats have been extended
for having a wider contact surface.
Stanchions are fitted into lower crown through a cryogenic process
called “Cryofit” that cools down stanchions using liquid nitrogen
and heats up lower crown at about 100 ° C.
No pressing device is used for next mating. Forced fitting does not
eliminate surface friction, but it allows creating an undetachable
assembly once room temperature has been reached.
IMPORTANT !
Never remove any parts!

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ARCH-SLIDER MONOLITH ASSEMBLY
This year new feature is the stanchion and arch integrated casting
in magnesium alloy.
This unit ensures maximum stiffness with limited weight.
Apart from its interesting make design, the particular shape of the
arch has a wide front side offering large wheel opening, avoiding
undesired mud deposit.
Sliding surfaces inside sliders, seals and securing bolts seats and
wheel shaft lugs are machined by NC machines.
IMPORTANT !
If a disc brake system is installed, it is possible to change pins (1)
retaining Cantilever or V-brake levers with screws (part no.
532979QF) available as spare parts.
1

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1
Models featuring arch and sliders in two materials and glued
together are still being produced.
This procedure determines an assembly practically inseparable
exploiting also pins (1), retaining Cantilever or V-brake levers, as
a joining point between the two parts.
IMPORTANT !
Never disconnect the two components!
If a disc brake system is installed, it is absolutely forbidden to
loosen and remove original pins (1).
If needed, replace these pins with screws (part no. 532979QF)
available as spare parts.
IMPORTANT: screw threading is treated to ensure hydraulic seal.
Never reuse screws which have been removed.

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OIL LEVEL
The required amount of SAE 7.5 oil is used in all fork models.
Apart from possible adjustments through external adjusters, air
volume into the fork leg can be modified for fork top
performance by increasing/decreasing oil level. In fact, oil
amount can affect fork behavior decisively under different working
conditions.
For improved fork progression, lightly change starting volume of air
chamber positioned over oil level mark according to rider’s weight.
To avoid frequent stops against fork bottom and improve second
part of fork compression. air volume may be decreased. A ± 10%
from specified height is allowed.
Table below gives indications on oil level (H) into the stanchion
tube (with tubes at the end of their stroke into the sliders and
removed springs and pre-load tubes).
IMPORTANT: small amounts of oil within the turns of the spring
removed from the leg can give a distorted value for original air
volume.
To change rebound speed, in models with no adjusters, use
different grade oil. Please note that the rebound speed decreases
as oil density increases.
“OPEN-BATH” HYDRAULIC SYSTEM
All M ARZOCCHI forks are equipped with “open-bath” hydraulic
system, that is the oil flows freely inside the fork legs, thus helping
lubricating and cooling down all moving parts and avoiding all
problems linked to sealed systems.
M ARZOCCHI engineers have been successfully using this system for
several years in the motorcycle field. Apart from the above benefits,
it also reduces the oil quantity needed inside each fork leg.
H
H

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AIR PRESSURE
Apart from oil amount in fork legs, in air forks also pressure of air
chamber into stanchions can be changed for different fork response
according to rider’s weight and to stresses.
New air fork this year is MARATHON model, featuring inner
separated air chambers that determine load damping during
compression (positive air) and rebound (negative air).
The positive air chamber is in both fork legs, while the negative air
chamber is only in the LH fork leg.
Table below indicates recommended pressure values according to
different rider’s weight classes. Values are indicative only as riding
style and ground conditions must also be considered.
R ECOMMENDED PRESSURE / A CCORDING TO RIDER ’ S WEIGHT
R IDER ’ S WEIGHT P RESSURE
kg lbs. bar psi
55 ÷ 70 120–155 2–2,7 29–40
70 ÷ 80 155–180 2,5–3 37–44
80 ÷ 100 180–220 3–3,5 44–51
90 ÷ 100+ 210–220+ 3,5–4,5 51–66
A thicker oil (SAE 10) will cause a slower rebound, whereas a
more fluid oil (SAE 5) will cause a quicker rebound.
Positive air
Negative air

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SPRING PRELOAD
For optimal suspension operation and best use of the useful travel,
spring preload must be as low as possible.
Springs must be able to bear the biker’s weight, being at the lowest
possible preload degree. Suspension sagging under the biker’s
weight (“sag”) must be about 1/4 of the fork actual travel. Should
this not be the case, it is recommended the springs be replaced with
harder ones, instead of overloading them.
When adjusting the preload, please also consider the friction
generated by the fork sliding parts due to the frontal load transmit-
ted while braking or passing obstacles at a high speed.
Preload knobs or adjusters on the stanchion tube plugs are of the
screw type. When turned, they produce a screw compression of
about 15 mm.
In air-operated forks, the preload value is determined by the
pressure inside the fork legs.
IMPORTANT !
It is recommended to position the preload adjusters or adjust the
internal pressure to the same value on both fork legs.

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REBOUND ADJUSTMENT
The fork legs section views show the hydraulic configuration
determining rebound load damping.
The figure shows two spring fork legs: “A”type uses a hydraulic
pumping element, anchored to the slider bottom, with limit switch
lock spring and adjusting knob that can be reached from fork leg
bottom.
The pumping element is completely immersed in oil that carries out
the hydraulic and cooling function. Oil passes through special holes
-that are partially closed according to the position of the adjusting
knob- and determines fork damping response in rebound phase.
“B”type uses a hydraulic cartridge with inner piston connected to
rod. At rod top an adjusting screw determines the opening of oil
hole. Cartridge is immersed in oil.
At cartridge case bottom there is a valve reacting to the fork leg
movements during rebound phase.
AB