Marzocchi Jr. T User manual

Jr T
Q
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,,,
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45 37
9
12
13
18
17
16
15
14
28
34
11
4
2
10
8
6
20
39 40
3
26
32
31
31A
31B
33
21
22
7
8A
25
24
1
35
36
36
36
19
29
30
38
23
27
44
41 42
43

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248.5
20
26.5
2243
504.2
455.2
±2
L.MAX.=708 L.L.=698 L.MIN.=568
±2
TRAVEL 130
49 193.8
276.8
15
35
172.8
Ø28.6
Ø30
±0.1
+0.05
0
178
348
82
80
110
130
10 10
GENERAL
• The Jr. T double clamp fork is specifically designed for Downhill
use.
• TheJr.Tforkissprungbyamechanicalspringanduseshydraulic
rebound damping.
• Spring pre-load adjustment controlled via external top mount
adjuster, rebound damping adjustment controlled by adjuster
inside each fork leg.
• Stanchiontubesecuredtothecrownandupperplate.Thesystem
is equipped with full length 360º slider bushings giving this fork
an incredibly smooth stiction free stroke, in addition to un-
matched structural strength.
• Parts subjected to friction are cooled and lubricated by a
specially formulated oil.
• Brake caliper adapter available, fits onto LH slider.
Steer tube: in CrMo steel with variable butting. Several lengths
available in non threaded 1 1/8” diameters. EASTON aluminum
steer tubes available for 1 1/8”, threadless.
Crown: Forged and CNC-machined BAM
❊
aluminum alloy.
Upper plate: CNC-machined T6-6082 alloy.
Arch: CNC-machined ERGAL alloy.
Stanchions: Anodized special aluminum.
Sliders: Forged and CNC-machined BAM
❊
aluminum alloy.
Slider bushing: Fulllengthguidebushingcomposedofacopper
base and impregnated with an anti-friction coating.
Seals: Computer designed oil seals guarantee the highest quality
seals available.
Oil: Specially formulated oil which eliminates foaming and viscos-
itybreakdownwhile providingcompletestiction-free performance.
Fork leg oil: 175 cc type EBH 16- SAE 7.5.
❊
BAM: Bomber Aerospace Material.
Special alloy extracted from aerospace material.

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GENERAL RULES FOR
CORRECT OVERHAULING
AND MAINTENANCE
1. Where specified, assemble and disas-
semble the shock absorption system
using MARZOCCHI special tools only.
2. On reassembling the suspension sys-
tem, always use new seals.
3. Iftwoscrewsarecloseonetotheother,
alwaystightenusinga1-2-1sequence.
In short, screw the first screw just up to
thepointitiswelltightened,thentighten
the second screw and then go back to
the first one and screw it tighter.
4. Clean all metal parts with a special,
preferablybiodegradablesolvent,such
astrichloroethaneortrichloroethylene.
5. Beforereassembling,lubricateallparts
in contact with each other using sili-
cone fat spray or a specific oil for oil
seals.
6. Always grease the conic seal rings
before reassembling.
7. Use wrenches with metric size only.
Wrenches with inch size might dam-
age the fastening devices even when
theirsizeissimilartothatofthewrenches
in metric size.
INSTRUCTIONS

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FAILURES, CAUSES AND REMEDIES
Thisparagraphreportssomefailuresthatmayoccurwhenusingthefork.Italsoindicatespossiblecausesandsuggestsaremedy.Always
refer to this table before doing any repair work.
Oil leaking through the bottom of slider O-ring seal on the pumping assy screw is
damaged Replace the O-ring seal
Excessive oil build up on stanchions 1. Oil seal is worn out
2. Stanchion tube is scored
3. Excessive dirt on oil seal
1. Replace oil seal
2. Replace oil seal and stanchion tube
3. Clean the oil seal seat and replace oil
seal
Fork has not been used for some time and
is locked out Oil seals and dust seals tend to stick to stanchion tube Raise dust seal and lubricate stanchion tube, dust seal and oil seal
Excessiveplayofstanchionsintothesliders Main slider bushings are worn Replace main slider bushings
FAILURES CAUSES REMEDIES

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RECOMMENDATIONS FOR
MAINTENANCE
MARZOCCHI forks are based on ad-
vanced technology, supported by year-
long experience in the field of profes-
sionalmountainbiking.Inordertoachieve
best results, we recommend to check and
cleantheareabelowthedustsealandthe
stanchion tube after each use and lubri-
cate with silicone oil.
INSTALLATION
InstallingtheJr.Tforkonabicycleisavery
delicate operation that should be carried
out with extreme care.
A threadless steer tube is pre-installed on
the fork from the factory. It will need to be
cut to the required length for a proper fit.
Always have the installation checked at
one of our Technical Service Centers.
WARNING: “A-Head Set” head-
set/Steering tube mounting and
adjustment must be carried out in compli-
ance with the headset manufacturer’s in-
structions.Improperinstallationmayjeop-
ardize the safety of the rider.
Havesteertubereplacedatanauthorized
Technical Service Centers only.
WARNING: In case of improper
installationof thesteer tubeinto the
crown, the rider could lose control of his/
her bicycle, thus jeopardizing his/her
safety.
MOUNTING THE FORK ON THE
FRAME
FIG. A
Remove the upper plate (35) from steer
tube and fork legs by loosening the 3
fastening bolts (36).
35
36

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FIG. B
Assemble the fork to the frame complete
with headset. Fit the upper plate (35) into
the upper stanchions and the steer tube.
35
FIG. C
Thestanchionsedge(13)mustbealigned
with or slightly lower than the upper plate
(35).
If fork legs overprotrude, fit some spacers
(D) to the plate close to the steer tube.
35
D
13
FIG. D
Fit the handlebar support and the A-Head
Set plug over the upper plate (35) and
then adjust the steering.
Now finally tighten the 3 bolts (36) on the
upper plate to 9 Nm.
IMPORTANT:Loosenthe3screws
(36) on the upper plate before ad-
justing the steering. Tighten the above
bolts to the specified torque when fin-
ished.
36
Nm9

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FIG. F
Tighten the 4 stanchions fastening screws
(28) onto the crown to 11 Nm.
WARNING: do not overtighten
the screws holding the stanchions
to the crown as this may distort the stan-
chion tubes and weaken the whole struc-
ture.
Afteranyinstallation alwayscheckfor the
following:
– proper torque of bolts fastening stan-
chion tube onto lower crown and up-
per plate;
– proper torque of bolts fastening brake
arch onto slider (11 Nm).
28
13
Nm 11
FIG. E
If the crown (34) position with respect to
thestanchiontubes(13)hasbeenchanged
for any reason, adjust the original dis-
tance.
– Distance “H” between crown and tyre
edge (when inflated) should not be
lower than total travel (130 mm) + 3
mm.
WARNING: If steering crown is
improperly matched with stan-
chions, it may touch the tyre and cause
severe injuries to the rider.
H

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FRONT WHEEL ASSEMBLY (FIG. G)
IMPORTANT: fixing the front
wheel properly as specified in the
instructionsgivenbelowisessentialforthe
proper operation of this fork and all re-
lated devices, and therefore for safe rid-
ing. You are advised to follow these
instructions closely.
Slacken the lock nut of the quick release
lever so the hub will fit between the fork
sliders.
Make sure the quick release bushings (D)
are centered to the recesses in the sliders.
Lock the quick release lever (E) and make
sure the bushings (D) are properly seated
in the sliders.
D
E
WARNING:Theseslidersarespe-
cifically designed to fit this type of
hub.Donotuseanyhubdesignotherthan
that specified here, as this would not
ensure proper fastening of the wheel and
may lead to breakdown of the assembly
components.
DISC BRAKE SYSTEM ASSEMBLY
(FIG. H)
Assembling the brake caliper onto the
slider is a very delicate operation that
should be carried out with extreme care.
Improper assembly might overstress the
caliper supports, which might break.
Screwthecalipersupport(42)totheslider
(20)using the screws (43) andplate (41).
IMPORTANT: Clean the mating
surfaces inside and outside slider,
otherwise dirt may affect caliper position
orcausethescrews(43)tobecomeloose.
Tighten the screws (43) to 9 Nm.
Wheninstalling the discbrake system, be
sure to properly follow the instructions
given by the manufacturer.
Nm9
20
41
43
42

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ADJUSTMENT
SPRING PRELOAD (FIG. I)
Spring preload can be adjusted by turn-
ingtheknob(2)onthetopof the forklegs.
When supplied, Jr.T is preloaded at its
minimum level, i.e. adjustment knob com-
pletelyunscrewedcounterclockwise.How-
ever, springs are slightly preloaded to
counteractstatic loads duringCOMPRES-
SION. By turning the adjuster knob clock-
wise, the preload is increased up to the
maximum value equal to 15 mm spring
preload. This adjustment is essential in
order to have the right Jr.T response in
accordance with the rider’s weight and
riding style.
2
REBOUNDDAMPINGADJUSTMENT
(FIG. L)
TheadjustercontrollingREBOUNDdamp-
ing adjustment is accommodated inside
cartridge rod (11) inside each fork leg.
To access the adjuster, unscrew the top
caps (37) and push the stanchion tubes
fully down (see Fig. 1).
Slide out the pre-load sleeve (1). Fit the
supplied hexagon rod (C) into the stan-
chion tube and into the adjuster inner
hole. Rotate the adjuster clockwise for
harderdamping, counterclockwise tosof-
tenit.Refitthecap(37)andtightenittothe
specified torque (see fig. 25).
WARNING: Do not remove the
springs or this will alter the amount
of oil inside the fork legs.
C

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▲
▲
▲
▲
▲
▲
▲
▲
▲
▲
▲
▲▲
▲
▲
▲
▲
DISASSEMBLY
GENERAL
– The reference numbers given in this section relate to the components shown in the fork exploded view.
– Operations refer to the fork legs already removed from the upper plate and from the crown and disassembled from the brake arch.
– Before starting any operation. please read the diagram below. It shows the quickest procedure and the exact disassembling
sequence. Start from the part to be disassembled and then follow the arrows to remove the other parts.
DISASSEMBLY DIAGRAM
SPRING FIG. 2
FOOT BUFFER FIG. 10
CARTRIDGE ROD FIG. 10
FOOT NUT FIG. 3
STANCHION TUBE CAP FIG. 1
DUST SEAL FIG. 5
STOP RING FIG. 6
OIL SEAL FIG. 7
CARTRIDGE ROD CHANGE
VALVE ASSEMBLY CHANGE
STOP RING FIG. 11
VALVE ASSEMBLY FIG. 11
GUIDE BUSHING AND SEAL
ASSEMBLY CHANGE
SPRING CHANGE
REBOUND SPRING FIG. 10
STANCHION TUBE FIG. 4
UPPER WASHER FIG. 8
GUIDE BUSHING FIG. 9

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SPRING CHANGE
FIG. 1
Placethe stanchiontube (13)in a vice.Be
sure not to damage or squeeze stanchion
in the process. Unscrew the plug (5) with
a 26 mm hexagon wrench.
Removetheplugcompletewiththe O-ring
(6) from the stanchion tube.
FIG. 2
Pushthestanchion tubeintothe sliderand
removetheupperwasher(27),thepreload
sleeve (1) and the spring (9).
Make all necessary changes.
GUIDE BUSHING AND
SEAL ASSEMBLY CHANGE
FIG. 3
Let all the oil drain out.
WARNING: Remembertoalways
recycle any used oil.
To change the fork leg oil follow the
procedure as described in section
“REASSEMBLY” from Fig. 22 to Fig. 25.
Turn the fork leg upside-down and un-
screw the foot nut (22) complete with O-
ring (21) by the use of a 15 mm socket
wrench.
56
9
27
1
22
21

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FIG. 4
Withdraw the stanchion tube (13) from
the slider.
13
14 15
FIG. 5
Remove the dust seal (14) from the top of
slider using a small screwdriver.
FIG. 6
Remove the stop ring (15) from the slider
byplacingthescrewdriverbitinoneofthe
three openings on the stop ring.
IMPORTANT:whenremovingthe
stopring,makesurenottodamage
its seat.

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FIG. 7
Fit the slider protector (A) onto the slider
and remove the oil seal (16) with the help
of a large flat screwdriver.
IMPORTANT:whenremovingthe
oil seal, make sure not to damage
its seat. Do not reuse any oil seals you
have removed.
16
A
17
18
FIG. 8
Remove the upper washer (17) from the
slider.
FIG. 9
Fitthebitofasmallscrewdriverintoupper
edgeslotoftheguidebushing(18)andlift
gently. Pull the bushing out of the slider
and make all necessary changes.

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CARTRIDGE ROD CHANGE
FIG. 10
Remove the foot buffer (33) from the
cartridge rod (11) end.
Withdraw the cartridge rod (11) and the
rebound spring (12) from the stanchion
tube opposite side. Replace the seal ring
(26) if damaged or worn out.
26
12
33 11
32
31
VALVE UNIT CHANGE
FIG. 11
To check that the valve unit is operating
correctly, it is necessary to work on the
inside of the stanchion tube.
Slip off the stop ring (32) using pointed
pliers.
Putthevalveunit (31) outofthetube in the
same sequence as in the figure.

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REASSEMBLY
CAUTION: before reassembling,
all metal components should be
washed carefully with inflammable, pref-
erably biodegradable, solvent and dried
with compressed air.
GUIDE BUSHING AND
SEAL ASSEMBLY
FIG. 12
Check for any debris or dirt lodged be-
tweensliderand bushing.Insertthe guide
bushing (18) into the slider making sure it
becomes properly seated against slider
walls.
18
17
16
B
FIG. 13
Fittheupper washer(17)into the sliderso
that it comes in contact with the guide
bushing.
FIG. 14
Lubricatetheoilseal(16)andfititontothe
seal press (B) - its hollow side toward the
slider.
Press the oil seal until it touches the lower
washer by using the above seal press.

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FIG. 15
Insert the stop ring (15) and make sure it
is properly fitted into its seat.
15
11 12
26
31
33 11
VALVE UNIT AND CARTRIDGE ROD
ASSEMBLY
FIG. 16
After having overhauled or replaced the
valve unit and after having cleaned the
inside of the tube, reassemble. Assemble
valve unit components (31), in correct
sequence.
Then fit cartridge rod (11), seal ring (26)
and rebound spring (12) into the valve
unit (31).
FIG. 17
Reassemble the foot buffer (33) onto the
end part of cartridge rod (11).

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FIG. 18
Fit this assembly into the stanchion tube
(13)andproperlyseatthevalveassembly
(31).
Insert the stop ring (32).
13
32
31
13
14
STANCHION TUBE ASSEMBLY
FIG. 19
Fit the stanchion tube (13) gently into the
oil seal (16).
Rotatethestanchiontubewhileinsertingit
into the seal to reduce the chance of
damaging the seals.
Turn the slider over and check that car-
tridge rod thread (11) is sticking out
through the slider hole. If not so, press on
hexagon rod to push out cartridge rod.
FIG. 20
Lubricatethedustseal(14)andseatitinto
the stanchion.

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FIG. 21
GreasetheO-ring(21)onthefootnut(22)
and screw the nut onto cartridge rod
thread (11).
Tighten to 12 Nm.
Pump stanchion up and down several
timestomakesureitslidesproperlythrough
the stroke.
22
21
Nm12
95
9
HOW TO FILL WITH OIL
FIG. 22
Pour the oil little by little when the stan-
chion tube is fully down and then pump
stanchiontubeupanddownsoastohave
a better filling. Check that the oil level is
95 mm/3.74 in. from the top of the
stanchion tube, in both legs.
SPRING AND PRELOAD CAP
FIG. 23
Fit the spring (9) into the stanchion tube.

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FIG. 24
Fit the preload sleeve (1) and the top
washer (27) into the stanchion tube.
27
1
FIG. 25
Lubricate the O-ring (6) on the cap (5).
Turn the plunger (7) inside the cap
counterclockwise until it is at its minimum
setting.
Start the complete cap assembly onto
stanchiontube thread byhand. Tightento
12 Nm.
Fit the brake arch to the fork leg, and then
install fork legs into crown and upper
plate as specified in section “INSTALLA-
TION”.
Nm12
56

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SPECIFIC TOOLS
Ref. Item. Description and use
A 536003 AB Slider protector: to remove the oil seal from the slider
B R 5068 Oil seal press: to press oil seal into the slider
C R 5084 Hexagon wrench: to set rebound adjuster
B
C
A