SHERCO 125 SE-R 2017 Instruction manual

MANUEL D’ATELIER I WORKSHOP MANUAL I MANUAL DE
TALLER

125 SE-
R
2
CONTENTS
PREAMBLE.......................................................................................................................................................................................................................................................................................................................................................................................................4
LISTOFENGINETOOLS..........................................................................................................................................................................................................................................................................................................................................................................5
TECHNICALCHARACTERISTICS......................................................................................................................................................................................................................................................................................................................................................6
❱❘ Engine......................................................................................................................................................................................................................................................................................................................................................................6
❱❘ Cyclepart.................................................................................................................................................................................................................................................................................................................................................................7
ORIGINALSETTINGS.................................................................................................................................................................................................................................................................................................................................................................................8
❱❘ Yoke..........................................................................................................................................................................................................................................................................................................................................................................8
❱❘ Shockabsorber....................................................................................................................................................................................................................................................................................................................................................9
OPERATIONSREQUIRINGENGINEREMOVALORNOTI.............................................................................................................................................................................................................................................................................................10
ENGINEREMOVAL/ASSEMBLY.....................................................................................................................................................................................................................................................................................................................................................11
❱❘ Engineremoval..................................................................................................................................................................................................................................................................................................................................................11
❱❘ Reassemblyoftheengineintoitsframe...................................................................................................................................................................................................................................................................................................12
ENGINEDISASSEMBLY.........................................................................................................................................................................................................................................................................................................................................................................14
❱❘ Gearboxdrainage.............................................................................................................................................................................................................................................................................................................................................14
❱❘ Removalofthepinionandselector.............................................................................................................................................................................................................................................................................................................14
❱❘ Removalofthecylinderhead,thecylinderandthepiston.................................................................................................................................................................................................................................................................15
❱❘ Disassembletheclutchcasing.....................................................................................................................................................................................................................................................................................................................16
❱❘ Removalofboththepressuretrayanddiscs.........................................................................................................................................................................................................................................................................................16
❱❘ Removaloftheelectricstarter........................................................................................................................................................................................................................................................................................................................17
❱❘ Removalofthemaintransmission.............................................................................................................................................................................................................................................................................................................17
❱❘ Removalofthelockingmechanism...........................................................................................................................................................................................................................................................................................................18
❱❘ Removaloftheignitioncasing.......................................................................................................................................................................................................................................................................................................................19
❱❘ Removaloftheignition.....................................................................................................................................................................................................................................................................................................................................19
❱❘ Removalofthestarter......................................................................................................................................................................................................................................................................................................................................20
❱❘ Intakepipeandclapperbox...........................................................................................................................................................................................................................................................................................................................20
❱❘ Separateoutthehalf-casings........................................................................................................................................................................................................................................................................................................................21
❱❘ Removalofthespeedselection...................................................................................................................................................................................................................................................................................................................21
❱❘ Removaloftherodassembly.......................................................................................................................................................................................................................................................................................................................22
ENGINEPARTCONTROL.....................................................................................................................................................................................................................................................................................................................................................................23
❱❘ Connectingrodassembly..............................................................................................................................................................................................................................................................................................................................23
❱❘ Balancemasses,verificationoftheexteriorside....................................................................................................................................................................................................................................................................................23
❱❘ Radialclearanceofthecrankhead............................................................................................................................................................................................................................................................................................................23
❱❘ Crankheadlateralclearance........................................................................................................................................................................................................................................................................................................................24
❱❘ Controlofthecrankshaftradialrunout........................................................................................................................................................................................................................................................................................................24
❱❘ Piston......................................................................................................................................................................................................................................................................................................................................................................24
❱❘ Cross-sectionalclearance..............................................................................................................................................................................................................................................................................................................................24
❱❘ Standardexchangecylinder/Squishcontrol.........................................................................................................................................................................................................................................................................................26
❱❘ Disassembletheexhaustvalvesystem...................................................................................................................................................................................................................................................................................................27

3
❱❘ Controlofvalveoperations.............................................................................................................................................................................................................................................................................................................................29
❱❘ Adjustmentoftheexhaustvalvepulleyclearance................................................................................................................................................................................................................................................................................30
❱❘ Clapperbox,pipeintakesleeve...................................................................................................................................................................................................................................................................................................................31
❱❘ Clutch......................................................................................................................................................................................................................................................................................................................................................................31
ENGINEREASSEMBLY..........................................................................................................................................................................................................................................................................................................................................................................32
❱❘ Connectingrodassembly..............................................................................................................................................................................................................................................................................................................................32
❱❘ Transmissiongearbox.....................................................................................................................................................................................................................................................................................................................................32
❱❘ Assemblyofthehalf-casings.........................................................................................................................................................................................................................................................................................................................33
❱❘ Selectionmechanism......................................................................................................................................................................................................................................................................................................................................34
❱❘ Maintransmissionandclutch........................................................................................................................................................................................................................................................................................................................35
❱❘ Clutchdiscs,pressureplate............................................................................................................................................................................................................................................................................................................................36
❱❘ Clutchcasing........................................................................................................................................................................................................................................................................................................................................................36
❱❘ Pistonandcylinder.............................................................................................................................................................................................................................................................................................................................................37
❱❘ Cylinderhead......................................................................................................................................................................................................................................................................................................................................................37
❱❘ Clapperboxandpipeintake..........................................................................................................................................................................................................................................................................................................................38
❱❘ Gearboxoutputpinion......................................................................................................................................................................................................................................................................................................................................38
❱❘ Assemblyoftheignitionstarter......................................................................................................................................................................................................................................................................................................................38
❱❘ Ignitionassemblyanditslid.............................................................................................................................................................................................................................................................................................................................39
❱❘ Assemblyoftheelectricstarter......................................................................................................................................................................................................................................................................................................................39
TABLEOFTIGHTENINGTORQUES...............................................................................................................................................................................................................................................................................................................................................40
TABLEOFCARBURETTORSETTINGS.......................................................................................................................................................................................................................................................................................................................................42
❱❘ TableofsettingsfortheSE-R125carburettor:.......................................................................................................................................................................................................................................................................................42
LOADCIRCUITCONTROL....................................................................................................................................................................................................................................................................................................................................................................43
❱❘ Staticcontrolvalues(engineturnedoff)125SE-R...............................................................................................................................................................................................................................................................................43
❱❘ Dynamiccontrolvalues...................................................................................................................................................................................................................................................................................................................................43
WIREMAP........................................................................................................................................................................................................................................................................................................................................................................................................44
❱❘ Mainbundle6827..............................................................................................................................................................................................................................................................................................................................................44
❱❘ Lightbeam125SE-R......................................................................................................................................................................................................................................................................................................................................46
❱❘ Racinglightbeam125SE-R........................................................................................................................................................................................................................................................................................................................47
❱❘ Accessorybundle..............................................................................................................................................................................................................................................................................................................................................48

125 SE-
R
4
PREAMBLE
The present manual is primarily intended for certified mechanics working in an
appropriately equipped workshop.
Performing the various operations requires both a solid knowledge in mechanics and the set
of SHERCO tools specific to the 125 SE-R engines.
This workshop manual serves as a complement to the SHERCO 125 SE-R user’s manual.

5
LISTOFENGINETOOLS
❱❘ 125 SE-R
Tooling reference
Designation
1814
Clutch drum block
1815
Ignition block
2067
Oscillating arm shaft tool
2072
Right-hand casing primary shaft bearing tool
2074
Secondary shaft bearing tool
R467
Out-of-gearbox shaft bearing tool
2069
Out-of-gearbox gasket tool
2071
Right-hand drum bearing selection tool
5398
Left-hand drum bearing selection tool
5399
Crankshaft bearing tool
2069
Crankshaft gasket tool
5402
HK0808 needle bearing cage tool
(water pump, starter)
1968
Water pump gasket tool
1821
Engine support
1817
Primary pinion block tool
2073
Spring block (finger pointing device)
R462
Magnetic wheel wrench
R464
Crankshaft ring extractor
R453
Selected shaft bearing assembly tool
R444
Gasket selector tool

125 SE-
R
6
TECHNICALCHARACTERISTICS
❱❘ Engine
Type
Liquidcooled,2-strokesinglecylinder
Displacement
124.81CC
Borediameter/Stroke
54/54.5mm
Gasoline
Unleadedwithanoctaneindexofatleast95mixedwithtwo-strokeoil(2%)
Coolant
withforcedcirculation
Ignitionsystem
ADC-CDIwithoutacontactbreaker,digitaladvance
Sparkplug
NGKBR9ECMIX
Distancebetweensparkplugelectrodes
0.7mm
Piston
Forgedaluminium
Motoroil
500mlSAE10W40
Maintransmission
20x72
Gearbox:
1 st 2nd
3rd 4th
5th 6th
6speeds
15:33
17:30
19:28
21:26
23:24
25:22
Finaltransmission
13x51
Clutch
Multi-discinanoilbath,hydrauliccontrols
Ignition
Electricstarter
Battery
12V4Ah
Alternator
220W
❱❘ Carburettor
Typeofcarburettor
KEIHINPWK36SAG
Needleposition
3rdpositionfromthetop
Injectorneedle
N1EG
Maininjector
KEA168(KEA115)
Brakinginjector
KEP42(KEA38)
Starterinjector
85(50)
Openingoftheairregulatorscrews
1T1/4
Slidinggatesection
5.5

7
TECHNICALCHARACTERISTICS
❱❘ Cycle part
Frame
Semi-perimeter made of CrMo steel with an aluminium back clip
Yoke
WP suspension X Plor Ø48 mm
Rear suspension
WP suspension with a separate cylinder, oscillating aluminium arm
Front/back stroke
300/330 mm
Front brake
disc Ø 260 mm
Rear brake
Disc Ø 220 mm
Disc brakes
Wearing limit: 2.7 mm front and 3.6 mm rear
Front tyre
90/90-21’’
Rear tyre
140/80-18’’
Front/rear off-road pressure
0.9 bar
Gasoline tank capacity
10.4 l, including 1 litre in reserve
Steering column angle
25.9°
Wheelbase
1,465 mm

125 SE-
R
8
ORIGINALSETTINGS
❱❘ Yoke
Original settings - WP yoke suspension X Plor Ø48 mm
Compression
Comfort
14 clicks backwards
Standard
12 clicks backwards
Sport setting
10 clicks backwards
Recreation
Comfort
14 clicks backwards
Standard
12 clicks backwards
Sport setting
10 clicks backwards
Prestressing
Comfort
0 Clicks
Standard
1 Click (+3)
Sport setting
2 Clicks (+6)
Spring stiffness
Rider’s weight: 65-75 kg
3.8 N/mm
Rider’s weight: 75-85 kg
4.0 N/mm (origin)
Rider’s weight: 85-95 kg
4.2 N/mm
Type of oil
SAE 4
Measured oil level (compressed yoke
and without spring action) from the
top of the upper tube
110 mm

9
ORIGINALSETTINGS
❱❘ Shock absorber
Original settings - WP suspension shock absorber
Low-speed compression
Comfort
20 clicks backwards
Standard
12 clicks backwards
Sport setting
6 clicks backwards
High-speed compression
Comfort
2 revolutions backwards
Standard
1.5 revolutions backwards
Sport setting
1 revolution backwards
Recreation
Comfort
15 clicks backwards
Standard
12 clicks backwards
Sport setting
6 clicks backwards
Spring stiffness
Rider’s weight: 65-75 kg
42 N/mm
Rider’s weight: 75-85 kg
45 N/mm (original setting)
Rider’s weight: 85-95 kg
48 N/mm

125 SE-
R
10
OPERATIONSREQUIRINGENGINEREMOVALORNOTI
Operation requiring engine
removal
Operation not requiring engine
removal
Crankshaft (including the crank kit)
•
Complete gearbox
•
Crankshaft bearing
•
Gearbox bearing
•
Piston
•
Cylinder
•
Cylinder head
•
Ignition
•
Starter gear set
•
Complete clutch
•
Water pump
•
Speed selection assembly
•

11
ENGINEREMOVAL/ASSEMBLY
❱❘ Engine removal
- Drainage (see User’s Manual)
• Motor oil
• Coolant
- Remove the saddle.
- Disconnect the battery.
- Unhook the tank using its louvres.
- Disconnect the wire harness attached to the engine (starter lug, anti-parasitic device).
- Remove the exhaust (see User’s Manual).
- Remove the carburettor.
- Remove the secondary transmission chain (quick fasteners).
- Remove the chain protection.
- Remove the clutch slave cylinder.
- Remove the water hoses connected to the engine.
- Remove the left side radiator.
- Unscrew the entire set of engine screws.
- Loosen the oscillating arm shaft.
- Remove the cylinder head-frame retaining brackets and corresponding electric engine.
- Remove the engine shafts.
- Remove the oscillating arm shaft.
- Unhook the valve cables from their pulley.
- Remove the engine.
CAUTION
Once the clutch slave cylinder has been removed, the piston is no longer being maintained. Hold the piston pressed
down using a plastic collar.

125 SE-
R
12
ENGINEREMOVAL/ASSEMBLY
❱❘ Reassembly of the engine into its frame
For the reassembly step, proceed in the opposite order from disassembly, in complying with the tightening
torques of both screws and nuts: Engine screws: 60 N-m
Oscillating arm nut: 100 N-m
Clutch slave cylinder screws: 10 N-m
Cylinder head-frame screws: 23 N-m
- Remove the two M4 screws and withdraw the
valve pulley cover plate.
- Place the mapping contactor in the “Soft”
position (toward the left) and place the
motorcycle contact switch in the ON position.
Wait for completion of the electric engine valve
initialisation and its subsequent shut-off.
Turn off the motorcycle contact switch and
check that the pulley is correctly positioned
facing left.
- Proceed with the left cable tension adjustment
[1] so as to remove all slack from the pulley.
SOFT POSITION
1

13
ENGINEREMOVAL/ASSEMBLY
- Place the mapping contactor in the “Hard”
position (toward the right) and turn on the
motorcycle contact switch.
Wait for completion of the electric engine valve
initialisation and its subsequent shut-off.
Turn off the motorcycle contact switch and
check that the pulley is correctly positioned
facing right.
- Proceed with the right cable tension adjustment
[2] so as to remove all slack from the pulley.
- Verify the effective operations of valves by
placing the motorcycle contact switch in the ON
position and transitioning from the “Hard” curve
to the “Soft” curve.
HARD POSITION
2

125 SE-
R
14
ENGINEDISASSEMBLY
For the blow-up drawings, please refer to the 125 SE-R spare parts catalogue
❱❘ Gearbox drainage
- Remove drainage plugs [1] and [2], let the oil
flow out.
❱❘ Removal of the pinion and selector
- Unfold the safety washer tab [3] using a pushing
device.
- Remove the gearbox output pinion [4].
- Remove the screw first [5] first and then the
selector.
- Release the clutch control rod.
1
2
1
4
3
5
2

15
ENGINEDISASSEMBLY
❱❘ Removal of the cylinder head, the
cylinder and the piston
- Remove the shoulder screws [1] and release
both the cylinder head and the two O-rings
- Remove all four nuts [2] and proceed with
deinstallation.
- Conceal the casing.
- Remove the piston shaft clips.
- Release the piston shaft.
- Remove the piston and extract the needle
bearing from the connecting rod eye.
- Remove the base joint.
3
2
1
1
2

125 SE-
R
16
ENGINEDISASSEMBLY
❱❘ Disassemble the clutch casing
- Unscrew the water pump screws and cover.
Remove the form joint.
- Remove the screws first and then the clutch
casing. Extract the joint.
❱❘ Removal of both the pressure tray and discs
- Loosen the screws of the clutch pressure plate [1].
- Remove the screws, springs and spring plates.
1

17
ENGINEDISASSEMBLY
- Release both the pressure plate and discs from
the housing.
- Remove the support part [1] positioned in the
primary shaft.
❱❘ Removal of the electric starter
- Unscrew both screws [2]
❱❘ Removal of the main transmission
- Block the pinion at the end of the crankshaft
using tool reference 1817 [3].
- Unscrew the main transmission nut [4] and then
remove it with the tapered washer.
- Insert tool reference 1814 [6], which serves to
hold the drum and loosen the nut.
- Remove the tool.
- Remove the drum, the toothed washer, the
housing with the needle cage.
1
1
2
4
3
6

125 SE-
R
18
I
I
ENGINEDISASSEMBLY
- Removal of the main transmission pinion
❱❘ Removal of the locking mechanism
- With a screwdriver, push back on the scorpion so
that it no longer makes contact with the selection
star; next, remove the selection shaft.
- Unscrew the hex socket screw [2] and
remove the selection star [3].
CAUTION at the wedge and O-ring.
The main transmission pinion and clutch housing
crown match, which is why they cannot be
changed separately. They must always be
renewed as a pair.
CAUTION Be extremely careful with the washer
left at the casing bottom.
CAUTION when handling the selection star
indexation slug. The locking lever arm must only be
retracted when changing the casing.
1
2
3

19
ENGINEDISASSEMBLY
❱❘ Removal of the ignition casing
- Remove the screws first and then the ignition
casing with its gasket.
❱❘ Removal of the ignition
- Hold the steering wheel with tool 1815 [1] and
unscrew the shoulder nut [2].
- Introduce extractor R462 [3] and tear out the
magnetic wheel [4].
1
2
3
4

125 SE-
R
20
I
I
ENGINEDISASSEMBLY
❱❘ Removal of the starter
- Take out the starter [1]
❱❘ Intake pipe and clapper box
- Remove all 4 plastic hex sprocket screws [5].
- Remove the pipe, clapper box and
corresponding joint.
5
1