SHERCO 2023 WORKSHOP MANUAL-125-2T Motorcycle Instruction Manual

: June 13, 2024
: Sherco

Table of Contents

2023 WORKSHOP MANUAL-125-2T Motorcycle
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2023 WORKSHOP MANUAL-125-2T Motorcycle

Product Information: Product Name: 125SE-R Product Type:
Engine-powered cycle Manufacturer: Not mentioned Technical
Specifications: – Engine type: Not specified – Carburetor: Included
– Cycle parts: Included – Fork: Included – Shock absorber: Included
Operations Requiring Disassembly or Not Engine: –
Removing/Reinstalling the engine – Engine disassembly Engine Parts
Control: – Verification of the state of cylinder wear/piston Table
of Tightening Torques: – Provides information on the recommended
torque values for various components of the product. Table of
Carburetor Settings: – Provides information on the recommended
settings for the carburetor. Electrical Part: – Contains
information related to the electrical components of the product.
Diagnostic Tool Synerject: – A diagnostic tool used for
troubleshooting and diagnosing issues with the product. 1.1
Components Identification: – Provides an overview of the different
components of the Synerject diagnostic tool kit. 1.2 Description
Exxodiag Diagnostic Tools Ref: kit 8561: – Detailed description of
the Exxodiag diagnostic tool kit, specifically referencing kit
8561. 1.3 Diagnostic tool kit contents: – Lists the contents
included in the diagnostic tool kit. 1.4 Installation of the
diagnostic tool: – Instructions on how to install and set up the
diagnostic tool for use. Product Usage Instructions: 1. Forward: –
Read this section for general information and important
instructions before using the product. 2. Tools List 125SE-R: –
Refer to this section to get a list of tools required for assembly,
disassembly, and maintenance of the product. 3. Technical
Specification: – Review this section to understand the technical
specifications of the product, including engine, carburetor, cycle
parts, fork, and shock absorber details. 4. Operations Requiring
Disassembly or Not Engine: – This section provides instructions for
operations that involve disassembling or not involving the engine,
such as removing/reinstalling the engine and engine disassembly. 5.
Engine Parts Control: – Follow the instructions in this section to
verify the state of cylinder wear and piston condition. 6. Table of
Tightening Torques: – Use this table as a reference to ensure
proper tightening of various components of the product. 7. Table of
Carburetor Settings: – Refer to this table to adjust the carburetor
settings according to the recommended values. 8. Electrical Part: –
This section contains information regarding the electrical
components of the product. Follow the instructions provided for
electrical maintenance and troubleshooting. 9. Diagnostic Tool
Synerject: – Learn about the Synerject diagnostic tool and its
components in this section. 9.1 Components Identification: –
Familiarize yourself with the different components of the Synerject
diagnostic tool kit using the provided identification guide. 9.2
Description Exxodiag Diagnostic Tools Ref: kit 8561: – Read this
detailed description to understand the features and functions of
the Exxodiag diagnostic tool kit, specifically referencing kit
8561. 9.3 Diagnostic tool kit contents: – Review the contents of
the diagnostic tool kit to ensure you have all the necessary
components for diagnostic purposes. 9.4 Installation of the
diagnostic tool: – Follow the instructions provided in this section
to properly install and set up the diagnostic tool for use. Note:
For detailed step-by-step instructions on using and maintaining the
product, please refer to the complete user manual.

TABLE
FORWARD ……………………………………………………………………………………………………………………………. 4
TOOLS LIST 125SE-R ………………………………………………………………………………………………………………. 5
TECHNICAL SPECIFICATION ………………………………………………………………………………………………….. 6
ENGINE………………………………………………………………………………………………………………………………… 6
CARBURETOR …………………………………………………………………………………………………………………….. 6
CYCLE PART …………………………………………………………………………………………………………………………. 7
FORK…………………………………………………………………………………………………………………………………… 7
SHOCKABSORBER ………………………………………………………………………………………………………………… 8
OPERATIONS REQUIRING DISASSEMBLYORNOTENGINE…………………………………………………………….. 9
REMOVING / REISTALLING THE ENGINE…………………………………………………………………………….. 10
REMOVING THE ENGINE ……………………………………………………………………………………………………. 10
REINSTALLING THE ENGINE ……………………………………………………………………………………………… 10
ENGINE DISASSEMBLY ……………………………………………………………………………………………………… 11
Gear box drainage ………………………………………………………………………………………………………………………….. 11 Gear box drainage ………………………………………………………………………………………………………………………….. 11 Removal of the cylinder head / the cylinder / the piston ……………………………………………………………………….. 12 Disassemble the clutch cover …………………………………………………………………………………………………………… 13 Removal of both the pressure tray and discs ……………………………………………………………………………………… 13 Removal of the electric starter ………………………………………………………………………………………………………….. 14 Removal of the main transmission…………………………………………………………………………………………………….. 14 Removal of the locking mechanism …………………………………………………………………………………………………… 15 Removal of the ignition ……………………………………………………………………………………………………………………. 15 Removal of the starter……………………………………………………………………………………………………………………… 16 Intake pipe and clapper box……………………………………………………………………………………………………………… 16 Separate out the half casings …………………………………………………………………………………………………………… 16 Removal of the speed selection………………………………………………………………………………………………………… 17
ENGINE PARTS CONTROL …………………………………………………………………………………………………. 18
Connecting rod assembly ………………………………………………………………………………………………………………… 18 Balance masses, verification of the exterior side…………………………………………………………………………………. 18 Radial clearance of the crank head …………………………………………………………………………………………………… 18 Crank head lateral clearance ……………………………………………………………………………………………………………. 19 Control of the crankshaft radial runout……………………………………………………………………………………………….. 19 Piston ……………………………………………………………………………………………………………………………………………. 19 Cross sectional clearance………………………………………………………………………………………………………………… 20
1

Verification of the state of cylinder wear / Piston ………………………………………………………………. 20
Disassemble the exhaust valve system ……………………………………………………………………………………………… 21 Assemble the exhaust valve system………………………………………………………………………………………………….. 23 Exhaust valve setting ………………………………………………………………………………………………………………………. 24 Clapper box pipe, Pipe intake sleeve ………………………………………………………………………………………………… 25 Clutch ……………………………………………………………………………………………………………………………………………. 25 Connecting Rod Assembly……………………………………………………………………………………………………………….. 26 ……………………………………………………………………………………………………………………………………………………… 26 · Coat lubricant on the fork guiding tip and insert the rings [1] from the top ………………………………………….. 26 · Fasten the supporting washer[2] onto the secondary shaft ………………………………………………………………. 26 · Present the primary and secondary shafts together, then drive them into their respective bearings until reaching the stop. ………………………………………………………………………………………………………………………………. 26 · Hook the forks into the grooves of the moving pinions and insert the drum into its bearing ………………….. 26 Assembly of the half casings ……………………………………………………………………………………………………………. 27 Selection mechanism ………………………………………………………………………………………………………………………. 28 Main transmission and clutch……………………………………………………………………………………………………………. 29 Clutch discs pressure plate ………………………………………………………………………………………………………………. 30 Clutch casing………………………………………………………………………………………………………………………………….. 30 Piston and cylinder………………………………………………………………………………………………………………………….. 31 Cylinder head …………………………………………………………………………………………………………………………………. 31 Clapper box and pipe intake …………………………………………………………………………………………………………….. 32 Gearbox output pinion……………………………………………………………………………………………………………………… 32 Assembly of the ignition starter…………………………………………………………………………………………………………. 32 Ignition assembly and its cover…………………………………………………………………………………………………………. 33 Assembly of the electric starter…………………………………………………………………………………………………………. 33
TABLE OF TIGHTENING TORQUES …………………………………………………………………………………….. 34
TABLE OF CARBURETOR SETTINGS………………………………………………………………………………….. 35
ELECTRICAL PART ……………………………………………………………………………………………………………. 36
Electrical components ……………………………………………………………………………………………………………………… 36 1- Fan control …………………………………………………………………………………………………………………………………. 37 2-CDI …………………………………………………………………………………………………………………………………………….. 37 3-Checking voltage regulator ……………………………………………………………………………………………………………. 37 4-Battery check ………………………………………………………………………………………………………………………………. 38 5-starter check ……………………………………………………………………………………………………………………………….. 38 6-Checking the alternator…………………………………………………………………………………………………………………. 38 7-Checking the (crankshaft) hall sensor …………………………………………………………………………………………….. 39 8-Temperature sensor check ……………………………………………………………………………………………………………. 39 9-Checking the ignition coil ………………………………………………………………………………………………………………. 40 10-Checking the valve moto. ……………………………………………………………………………………………………………. 40
DIAGNOSTIC TOOL SYNERJECT) ……………………………………………………………………………………… 41
SYNERJECT) SYSTEM PRESENTATION ……………………………………………………………………………. 41
1.1- Components Identification …………………………………………………………………………………………………………. 41

1.2- Description Exxodiag diagnostic Tools Ref: kit 8561 …………………………………………………………………… 41 1.3- Diagnostic tool kit contents. ………………………………………………………………………………………………………. 42 1.4- Installation of the diagnostic tool……………………………………………………………………………………………….. 42
PRESENTATION OF THE SOFTWARE …………………………………………………………………………………. 46
2.1- Connection with keyless system………………………………………………………………………………………………… 46 2.2- Software settings ……………………………………………………………………………………………………………………………. 48 2.3- Update menu and synchronization …………………………………………………………………………………………….. 49 3 – Use of the software …………………………………………………………………………………………………………………….. 51 3.1 Identification ………………………………………………………………………………………………………………………………. 51 3.2 Reading trouble codes………………………………………………………………………………………………………………… 52 3.3 Erasing fault codes …………………………………………………………………………………………………………………….. 54 3.4 Actuator test ………………………………………………………………………………………………………………………………. 55 3.5 ECU update ………………………………………………………………………………………………………………………………… 57 3.6 Print screen function ………………………………………………………………………………………………………………….. 59
WIRING DIAGRAM ……………………………………………………………………………………………………………… 60
Main harness (Ref: 7107) ………………………………………………………………………………………………………………….. 60
WIRING DIAGRAM ……………………………………………………………………………………………………………… 61
Homologated light diagram (Ref: 8145)……………………………………………………………………………………………… 61 ………………………………………………………………………………………………………………………………………………………… 61
WIRING DIAGRAM ……………………………………………………………………………………………………………… 62
Racing light diagram (Ref: 6845) ……………………………………………………………………………………………………….. 62 ………………………………………………………………………………………………………………………………………………………… 62
WIRING DIAGRAM ……………………………………………………………………………………………………………… 63
Fan harness (Ref: 3577)…………………………………………………………………………………………………………………….. 63 ………………………………………………………………………………………………………………………………………………………… 63

3

125 SE-R

FORWARD
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

TOOLS LIST 125SE-R

Tooling reference 1814 1815 10480 2067 2072 2074 R467 2069 2071 5398 5399 2069 5402 1968 1821 1817 2073 R462 R464 R453 R444

Designation Clutch drum block Ignition block 125 SBS Valve tool control Oscillating arm shaft tool Right-hand casing primary shaft bearing tool Secondary shaft bearing tool Out-of-gearbox shaft bearing tool Out-of-gearbox gasket tool Right-hand drum bearing selection tool Left-hand drum bearing selection tool Crankshaft bearing tool Crankshaft gasket tool HK0808 needle bearing cage tool (water pump, starter) Water pump gasket tool Engine support Primary pinion block tool Spring block (finger pointing device) Magnetic wheel wrench Crankshaft ring extractor Selected shaft bearing assembly tool Gasket selector tool

5

125 SE-R

TECHNICAL SPECIFICATION

ENGINE

Type
Displacement
Bore diameter/Stroke
Gasoline
Coolant
Ignition system
Sparkplug
Distance between spark plug electrodes
Piston
Motor oil
Main transmission
Gearbox: 1st 2nd 3rd 4th 5th 6th

Liquidcooled,2-strokesinglecylinder
124.81CC
54/54.5mm
Unleadedwithanoctaneindexofatleast95mixedwithtwo-stroke oil (2%)
With forced circulation
ADC-CDI without a contact breaker, digital advance
NGKBR9ECMIX
0.7mm
Forge aluminum
500ml SAE 5W40
20×72
6speeds 15:33 17:30 19:28 21:26 23:24 25:22

Final transmission Clutch Ignition Battery Alternator

13×51 Multi-disc in an oil bath, hydraulic controls Electric starter 12V4Ah 220W

CARBURETOR
Type of carburetor Needle position Injector needle Main injector Braking injector Starter injector Opening of the air regulator
screws Sliding gate section

KEIHIN PWK36 SAG 3rd position from the top N1EE KEA170(KEA115) KEP42(KEA38) 85(50) 1T1/4
5.5

6

TECHNICAL SPECIFICATION
CYCLE PART

Frame
Fork
Rear suspension Travel Front/Rear
Front brake Rear brake Brake disc Front tire Rear tyre Pressure front / Rear Fuel tank capacity Angle of the steering column
Wheel base Weight (without fuel)
FORK

Semi-perimeter CrMo steel with aluminum sub frame
KAYABA USD Ø48mm Closed cartridge
KAYABA suspension with separate cylinder Aluminum swing arm
FACTORY 330/330mm RACING 300/330mm
rotor Ø 260mm rotor Ø 220mm Limit : 2.7mm front et 3.6mm rear
90/90-21” 140/80-18”
0.9 bar 10.4Ll with1 liter of reserve
25.9°
1465mm 95 kg

Settings Fork KAYABA USD Ø48 mm

Compression Rebound Spring Fork oil

Comfort Standard
Sport Comfort Standard
Sport Rider weight: 65-75 kg Rider weight: 75-85 kg
Rider weight: 85-95 01M

20 clicks back 13 clicks back 8 clicks back 18 clicks back 13 clicks back 10 clicks back 4.0N/mm (Original)
4.2N/m 4.4N/m 345 CC

7

125 SE-R

STANDARD ADJUSTMENT

SHOCK ABSORBER

Factory Settings KAYABA shock absorber

Low-speed compression High-speed compression Rebound Spring stiffness

Comfort Standard
Sport Comfort Standard
Sport Comfort Standard
Sport Rider weight : 65-75 kg
Rider weight : 75-85 kg

Type of oil

Rider weight : 85-95 kg

20 clicks back 14 clicks back 12 clicks back 2,5 turns back 1.5 turns back
1 turn back 15 clicks back 13 clicks back 11 clicks back
46N/mm
48N/mm (original)
50N/mm K2C

8

OPERATIONS REQUIRING DISASSEMBLY OR NOT ENGINE

Operation 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

Operation not requiring engine removal
· · · · · · · ·

9

125 SE-R

REMOVING / REISTALLING THE ENGINE
REMOVING THE ENGINE
WARNING To remove the engine, you must remove the swing arm axle, the swing arm and the rear wheel. To keep
the bike from falling, remember to support the chassis with an appropriate jack.
· Drain (refer to the owner’s manual) – the engine oil – the engine coolant
· Remove the seat. · Disconnect the battery. · Remove the fuel tank and its covers. · Disconnect all the electrical wiring connectors from the engine.
(Starter, TPS sensor, water temperature sensor, coil, fuel injector) · Remove the exhaust. · Remove the ignition coil. · Remove the fuel injector body. · Remove the chain. · Remove the chain guard. · Remove the clutch actuating cylinder.
WARNING When the clutch actuating cylinder is removed the piston is loose. Hold the piston it in place using a
plastic strap.
· Remove all of the water hoses connected to the motor. · Remove the left radiator. · Loosen all of the engine bolts. · Loosen the swing arm bolt. · Remove the brackets that attach the cylinder head to the chassis. · Remove the motor mounting bolts. · Remove the swing arm bolt. · Remove the motor.
REINSTALLING THE ENGINE
The motor should be reinstalled in the frame in the reverse order of how it was removed. The following torque values should be utilized.
Tightening torques:
Motor mounting bolts: 60Nm Swing arm axle nut: 100 Nm Clutch receiver screws: 10 Nm Cylinder head bracket bolts: 23Nm Exhaust mounting bolts: 10Nm
10

ENGINE DISASSEMBLY
Gear box drainage
· Remove drainage plugs [1] and [2], let
the oil flow out.
1

2

Gear box drainage

4

· Unfoldthesafetywashertab [3] usinga
pushing device.

· Remove the gearbox output pinion [4].

· Remove the screw first [5] first and then

the selector.

· Release the clutch control rod.

3

5

11

125 SE-R

ENGINE DISASSEMBLY
Removal of the cylinder head / the cylinder / the piston
1
· Remove the shoulder screws [1] and
release both the cylinder head and the two O-rings
· Remove all four nuts [2] and the
cylinder · Cover the casing.
2
· 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.
12

ENGINE DISASSEMBLY
Disassemble the clutch cover
· 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
· Release both the pressure plate and discs from the housing.
· Remove the support part [1] positioned in the
primary shaft. 1

13

125 SE-R

ENGINE DISASSEMBLY
Removal of the electric starter
· Unscrew both screws [2] 2 1
Removal of the main transmission
· Block the pinion at the end of the crankshaft
using tool reference 1817 [3].
· Unscrewthemaintransmissionnut[4]andthen remove it with the tapered washer.
3
· 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.
· Removal of the main transmissionpinion
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.

4 6
14

ENGINE DISASSEMBLY
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
CAUTION
Be extremely careful with the washer left at the casing bottom.

· Unscrew the hex socket screw [2] and remove the selection star [3].

CAUTION

When handling the selection star indexation

3

slug. The locking lever arm must only be retracted

when changing the casing.

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
15

3 2
125 SE-R

2 4

ENGINE DISASSEMBLY
Removal of the starter
· Take out the starter [1] 1
Intake pipe and clapper box
· Remove all 4 screws [2] · Remove the pipe clapper box and the gasket
2
Separate out the half casings
· Reposition the engine so that the ignition side is facing you.
· Remove all the fastening screws. · Now lift the left half-casing by gently striking the
gearbox output shaft with a plastic mallet in order to dislodge the other half-casing.
CAUTION
Avoid to the greatest extent possible introducing a screwdriver or any tool between the half-casingsfor the
purpose of separating them. Youmight damage the parting surface.
CAUTION
Be careful when working with the set rings of gearbox shafts. They might stay stuck inside the casing.
16

ENGINE DISASSEMBLY

Removal of the speed selection

· Remove the transmission gearbox lubrication

1

tube [1].

· Remove the two selector fork shafts [2] and
push them to the side to free the drum.

· Now disengage the selection drum from its bearing.

· The selector forks. Remove 1 2

CAUTION
During this removal step, be sure not to lose the small
rollers [3] on the fork caps.
Indicate the association of these rollers with the corresponding forks for purposes of reassembly.
1 3
· Remove both the primary and secondary shafts from their bearing

17

125 SE-R

ENGINE PARTS CONTROL
Connecting rod assembly
· If the roller bearings have been changed, then the internal ring that sits against the balance weight must also be changed.
· Heat the R464 tool to roughly 150°C, then immediately insert it onto the internal ring. Ensure that the tool sits squarely on the ring in order to more effectively transmit the heat and extract the ring
· To install the new ring, heat the tool once again to approx. 150°C. Next, insert the new ring and immediately position it on the reach of the connecting rod assembly
Balance masses, verification of the exterior side
· Using a caliper, measure the outer distance of the balance masses. Exterior value: 57.0 +/- 0.1 mm
Radial clearance of the crank head
· Install the crankshaft on the V and place a dial
gauge [A] against the crank head. · Push [B] the crank head first toward the gauge
and then in the opposite direction. The difference between these two measurements corresponds to the radial clearance. Crank head radial clearance:
Standard: 0.015 mm – 0.025 mm Tolerance limit: 0.06 mm If the radial clearance exceeds the tolerance limit, the crankshaft must be replaced
18

ENGINE PARTS CONTROL
Crank head lateral clearance
· Measuring the lateral clearance of the crank
head [A].
Crank head lateral clearance: Standard: 0.7 mm – 0.9 mm Tolerance limit: 1.15 mm If the clearance exceeds the tolerance limit, replace the crankshaft.

Control of the crankshaft radial runout
· Set the crankshaft on an alignment device or on shims laid out in a “V” pattern, and place a gauge as shown on the image.
· Now slowly turn the crankshaft. The maximum difference between the measurements corresponds to the level of crankshaft eccentricity.
Out-of-roundness: Standard: 0.03 mm maximum Tolerance limit: 0.05 mm
If the eccentricity is incorrect, replace the crankshaft or else align it to ensure lying within the tolerance limits.

Piston
If you introduce a piston that has already been in use, the following points would need to be verified:
Skirt: search for possible smears (clamping). Slight smears may be removed with a soft stone.
Segment grooves: The segments must not snag in their groove. To clean in this spot, an older segment or emery cloth (400-grain).
The segment retainers must be snugly fastened and not be worn parts.
Segments: Verify the condition and clearance at the cross-section.

19

125 SE-R

ENGINE PARTS CONTROL
Cross sectional clearance
· Insert the segment into the cylinder and install it with the piston (at approx. 10 mm from the upper edge of the cylinder).
· With a shim, it is possible to measure the cross- sectional clearance. Cross-sectional clearance: max. 0.40 mm
CAUTION
Should the clearance be greater than indicated, it would be necessary to check the condition of both the cylinder and piston. If these measurements lie within the tolerance dimensions, replace the segment.

Verification of the state of cylinder wear / Piston

· To detect cylinder wear, the bore diameter is measured using a micrometer located approx. 10 mm from theupperedgeofthecylinder.Takereadingsatseveralspotstoidentifythepotentialpresenceof ovalnes

Cylinder 125
Cylinder 125

Cylinder bore diameter 54.000 – 54.015 54.010 – 54.025
Piston Diameter 53.94 53.95

Piston A B
Piston A B

CAUTION
Lift thecylinderdiameterexceedsforexample 54.025mm,theinteriorwouldneedtoberelined(withNikasilcoating)or the cylinder replaced.
Before relining the cylinder, all exhaust valve parts would need to be disassembled. The piston size is engraved on the top of the piston, and the cylinder dimension is engraved on the right side cylinder.
Using a gauge, measure the height difference between the piston and the cylinder.
The clearance must be 0; otherwise, use another head gasket in order to obtain the desired value.

20

ENGINE PARTS CONTROL
Disassemble the exhaust valve system

Disassemble all parts, clean them, and verify their condition and state of wear. For this step, follow the disassembly and control procedure. · Remove the M10 [1] nut from the valve
shaft using a 13mm wrench
· Remove the two M5 screws [2] from the valve motor bracket and remove the bracket from the cylinder.

21

125 SE-R

ENGINE PARTS CONTROL
· Remove the washers [3] from the axle.
· Remove the connecting screw [4].
· Remove the M5 screw [5] and remove the right valve cover.
· Disassemble the half valves on either side of the cylinder.
CAUTION
Before to reassemble the valve, clean all the parts and making sure that there is no trace
of seizure on each side of the valve.
22

ENGINE PARTS CONTROL
Assemble the exhaust valve system
· Refit the two half valves then fit the right valve cover making sure that it is in the up position.
· Install the M5 screw without tightening it.
· Fit the connecting screw of the half-valves and tighten to 6 Nm.
· Fit back the setting washers on the valve shaft.

23

125 SE-R

ENGINE PARTS CONTROL
Exhaust valve setting
Position the valve motor bracket and tighten the M5 screws to 8 Nm.
Install the valve adjustment tool ref 10480 as indicated on the drawing. Position the exhaust valve against the stop on tool 8028 then tighten the valve shaft nut to 20 Nm.
One time all is in place and tightened, tighten the M5 screw [6] of the valve cover to 8 Nm.
6
Making sure that there is not too much lateral free play and that the valve assembly turn properly without hard point. In case of hard point or too much lateral free play, adjust it by changing shims on the valve axle.
24

ENGINE PARTS CONTROL
Clapper box pipe, Pipe intake sleeve
· Over time, the carbon tabs gradually lose their elasticity, which in turn causes a loss in power.
· Replace the worn or damaged gearbox. · Verifier the condition of the intake sleeve,
especially if it is not split.
Clutch

· Needle [3]: verify state of wear. · Push Rod [1] : Verify the state of wear:
Minimum length = 162,5mm
· Springs [14]:Verify the length.
Minimum spring length 37,5mm
· 8 lined discs [12]: Standard thickness: 2.95 mm / threshold thickness:
2.7 mm / deformation threshold: 0.3 mm
· 7 smooth discs [11]: Standard thickness: 1.4 mm / threshold thickness: 1.3
mm / deformation threshold: 0.3 mm

25

125 SE-R

ENGINE REASSEMBLY
For the blow-up drawings, please refer to the 125SE-R spare parts catalogue
Connecting Rod Assembly
· Insert the connecting rod assembly into the ball bearing by the top, in exercising precaution, until reaching the stop
CAUTION
The crank must be positioned on the cylinder side.

Transmission Gearbox

· Coat lubricant on the fork guiding tip and

insert the rings [1] from the top

· Fasten the supporting washer[2] onto the

secondary shaft

· Present the primary and secondary shafts

together, then drive them into their

1

respective bearings until reaching the stop.

CAUTION

Any fork used must be paired with its

original pinion as well as its roller.

2

· Hook the forks into the grooves of the moving pinions and insert the drum into its bearing

CAUTION
When hooking the forks into the drum pay special attention to prevent the rollers from
falling off of the tips

· Lubricate the fork axes and insert them into the forks. Drive the forks into their housing in the casing until reaching the stop

CAUTION
The gearbox shafts must now turn without hitting any hard points

26

ENGINE REASSEMBLY
Assembly of the half casings
· Install the transmission gearbox lubrication tube on the right-hand half- casing.
· Install the O-ring on the gearbox lubrication tube.
CAUTION.
Beware of the tube indexation, flat spot on the
oil plug rivet side.
· Ensure that the centering rings are in place on the right half-casing and moreover that the gearbox shaft washers are in their appropriate place.
· Lubricate the gaskets of the left half-casing and proceed with installation of this halfcasing.
· Introduce the screws and tighten them to 10 N-m.
· Next, use a plastic mallet to lightly strike the connecting rod assembly and verify that the shafts are turning without any hard point.

27

125 SE-R

ENGINE REASSEMBLY
Selection mechanism
· Place the spring into the casing with the curved strand pointing upwards.
· Insert the spacer, the locking finger andthe washer, then coat the CHC M6 x 20 screw with blue brake fluid and assemble all the parts.
· Hook the spring to the lever arm. The other end of the spring must lean
against the casing [1].
· Install the selection star indexation slug on the drum.
· Pull the locking lever arm backward in order to install the selection star.
· Coat the screw with blue brake fluid and then assemble the selection star on the
drum. [2] · Lubricate the axis of the now assembled selection and insert it into the needle bearings without neglecting the set ring.
· When the prong abuts the selection star, push it so that the shaft drops all the way to
the bottom. [3] · Verify whether the return spring strands are positioned against the finger in the casing on
both sides [4] · Install the selector and shift through all the speeds. Upon shifting through the entire range of speeds, the transmission gearbox shaft output needs to be rotated. Remove the selector once again.

1 2 3 4
28

ENGINE REASSEMBLY
Main transmission and clutch

· Lubricate the connecting rod assembly gasket.

· Install the half-moon wedge in its housing.

· Insert the pinion with the shoulder in a

2

downward position onto the crankshaft shank.

· Insert the washer [1], housing spacer and prelubricatedneedlecage [2] onthe mainshaft.

· Raise the clutch housing and its washer [3].
1 · Place the blue brake fluid on the main shaft
threading.

3
· Assemble the clutch drum and its nut on the main shaft in applying red brake fluid and a new safety washer.
· Introduce tool reference 1814 and tighten the nut to 100 N-m.
· Apply blue brake fluid on the crankshaft threading.
· Raise both the tapered washer and the nut.
· Block the main transmission using tool 1814 and then tighten the pinion nut at the end of the crankshaft to 100 N-m in adding red brake fluid.
· Remove tool 1814 and verify the absence of any hard point in the main transmission by turning the connecting rodassembly

29

125 SE-R

ENGINE REASSEMBLY
Clutch discs pressure plate
· Oil the push finger [1] and insert it onto the main
shaft. · Prior to the assembly step, oil the lined discs. · Begin with a lined disc. The 8 lined discs and the
7 smooth discs are positioned in an alternating pattern. · Install the pressure plate along with the springs, the spring plates and the screws.
1 · Tighten the screws to 10 Nm in a cross pattern.

Clutch casing

· Verify whether the two centering bushings are indeed well installed.

· Introduce the casing joint and hold it in place with a bit oflubricant.

· Stick the water pump set ring [2] with a bit of
lubricant.

· Present the clutch casing while ensuring that the water pump assembly has been properly installed. The connecting rod assembly needs to be rotated so that the water pump can mesh at the end of the crankshaft.
· Install the M6 hex sprocket screws and tighten to 10 Nm.

2
CAUTION.
Install a new joint on the M6X40 screw and on the coolant drainage screw.

· Verify that all shafts rotate without encountering any hard point

30

ENGINE REASSEMBLY

Piston and cylinder
· Oil the parts well before lifting. · Insert the needle bearing into the
foot crank, position the piston (the arrow on top of the piston is pointed toward the exhaust). · Place the shaft and clips with the open side downward. · Install the base joint. · Properly position the segments, with the reference pointing upward. · Insert the pre-fitted cylinder, fasten the cylinder with 2 nuts on opposite sides. · Raise the other two screws and washers, then tighten to 20 Nm.
Cylinder head
· Clean the parting surfaces of the cylinder as well as the cylinder head. · Position the 2 centering slugs on the cylinder. · Install the cylinder head. · Place the M8 shoulder screws with new copper washers. · Tighten three times and in a cross to 10 N-m.

31

125 SE-R

ENGINE REASSEMBLY
Clapper box and pipe intake
· Install a gearbox joint with new clappers. · Place the complete clapper box into the
intake pipe. · Assemble the intake pipe with the four M6
screws and its metal collar.
Gearbox output pinion
· Place the gearbox output pinion on the secondary shaft.
· Apply blue brake fluid on the threading. · Insert the safety washer. · Install the nut and tighten to 100 N-m. · Re-bend the safety washer release finger
on the nut
Assembly of the ignition starter
· Install the ignition starter. · Lubricate the pinions using spay-on grease.
32

ENGINE REASSEMBLY
Ignition assembly and its cover
· Place the half-moon wedge in its housing on the connecting rod assembly. · Insert the rotor on the connecting rod assembly. · Apply blue brake fluid on the threading. · Insert tool 1815, install the nut and tighten to 80 N-m. · Set up the 2 centering bushings. · Introduce a new joint and fasten the ignition cover.
Assembly of the electric starter
· Replace the O-ring on the starter by a new joint. · Apply a bit of lubricant on the O-ring. · Insert the starter into the right-hand casing. · Fasten the starter with the 2 hex sprocket screws.
· Finish the step by oiling and then inserting the clutch control rod into the main shaft [1].
· Assemble the speed selector with its screw and washer. · Assemble the two drainage plugs with a new joint
CAUTION.
The transmission gearbox needs to be filled when the engine is returned to its frame; otherwise, a portion of the oil will leak from the main shaft

33

125 SE-R

TABLE OF TIGHTENING TORQUES

Standard tightening torque M5 M6 M8 Chassis tightening torque Rear wheel nut Rear cradle fastening screw Front wheel nut Yoke foot clamping screw Brake pad axis screw Lower yoke tee clamping screw Upper yoke tee clamping screw Engine screw Oscillating arm nut Cylinder head – frame screw

Brake fluid 6 Nm 10 Nm 24 Nm Brake fluid 100 Nm 24 Nm 40 Nm 15 Nm 8 Nm 12 Nm 17 Nm 60 Nm 100 Nm 24 Nm

Engine tightening torque Break fluid Revolution sensor screw Coolant drainage screw Clutch slave cylinder screw Cylinder head, cross-patterned tightening torque

8 Nm 10 Nm 10 Nm 10 Nm

Crankshaft inspection plug Clutch pressure plate screw Water pump casing screw Ignition wheel nut Clutch drum nut Main transmission pinion nut Ignition casing screw Central casing screw Drum screw Starter screw Cylinder screw Gearbox output pinion nut

8 Nm 10 Nm 10 Nm 80 Nm 100 Nm 100 Nm 10 Nm 10 Nm 10 Nm 10 Nm 20 Nm 100 Nm

· ·
·
· · · · ·
34

TABLE OF CARBURETOR SETTINGS

ALTITUDE TEMPÉRATURE

3000 m To 2301 m