SHERCO 250 SE-R 2017 Instruction manual

MANUEL D’ATELIER I WORKSHOP MANUAL I MANUAL DE TALLER

250-300 SE-R
2
SUMMARY
FOREWORD ........................................................................................................................................................4
ENGINETOOLLISTFORUSE ........................................................................................................................................5
ENGINESPECIFICATIONS ...........................................................................................................................................6
❱❘ Engine ........................................................................................................................................6
❱❘ Chassis .......................................................................................................................................7
FACTORYSETTINGS ................................................................................................................................................8
❱❘ Front fork .....................................................................................................................................8
❱❘ Rear fork ......................................................................................................................................9
OPERATIONSPERFORMEDWITHTHEENGINEINANDOUTOFTHEFRAME .............................................................................................10
REMOVING/INSTALLINGTHEENGINE .............................................................................................................................11
❱❘ Removing the engine ......................................................................................................................11
❱❘ Reinstalling the engine ....................................................................................................................12
DISASSEMBLYOFTHEENGINE ...................................................................................................................................15
❱❘ Draining the transmission oil .............................................................................................................15
❱❘ Removing the sprocket and the gear selector ..........................................................................................15
❱❘ Removing the cylinder head, cylinder and piston ......................................................................................16
❱❘ Removing the clutch .......................................................................................................................17
❱❘ Removing the pressure plate and discs .................................................................................................17
❱❘ Removing the electric starter .............................................................................................................18
❱❘ Removing the primary drive gear ........................................................................................................18
❱❘ Removing the interlock mechanism .....................................................................................................19
❱❘ Removing the ignition cover ..............................................................................................................20
❱❘ Removing the electric starter double gear and the starter drive ......................................................................20
❱❘ Removing the flywheel ....................................................................................................................21
❱❘ Intake manifold and reeds ................................................................................................................21
❱❘ Separating the housing halves ...........................................................................................................22
❱❘ Removing the transmission components ...............................................................................................22
❱❘ Removing the crankshaft .................................................................................................................23
ENGINECOMPONENTS ...........................................................................................................................................24
❱❘ Crankshaft ..................................................................................................................................24
❱❘ Checking the crankshaft dimensions ......................................................................................................24
❱❘ Radial clearance of the big end ..........................................................................................................24
❱❘ Lateral play of the connecting rod .......................................................................................................25
❱❘ Checking the runout of the crankshaft ...................................................................................................25
❱❘ Piston .......................................................................................................................................25
❱❘ End gap .....................................................................................................................................25
❱❘ Remanufactured cylinder .................................................................................................................26

3
❱❘ Disassembly of the exhaust valve system ..............................................................................................27
❱❘ Checking the operation of the exhaust valve and the boosters .......................................................................31
❱❘ Adjusting the tension of the valve cables ...............................................................................................33
❱❘ Reed valves, intake manifold .............................................................................................................35
❱❘ Clutch .......................................................................................................................................35
REASSEMBLINGTHEENGINE .....................................................................................................................................36
❱❘ Crankshaft ..................................................................................................................................36
❱❘ Gearbox ....................................................................................................................................36
❱❘ Assembling the crankcase halves .......................................................................................................37
❱❘ Selector mechanism .......................................................................................................................38
❱❘ Clutch and primary drive ..................................................................................................................39
❱❘ Clutch discs, pressure plate ..............................................................................................................40
❱❘ Clutch housing .............................................................................................................................40
❱❘ Piston and cylinder ........................................................................................................................41
❱❘ Cylinder head ..............................................................................................................................41
❱❘ Reed valves and intake manifold ........................................................................................................42
❱❘ Transmission output sprocket ............................................................................................................42
❱❘ Mounting the starter drive .................................................................................................................42
❱❘ Installing the flywheel and the ignition cover ............................................................................................43
❱❘ Installing the electric starter ..............................................................................................................43
TIGHTENINGTORQUETABLE .....................................................................................................................................44
CARBURETORSETTINGTABLE ...................................................................................................................................46
❱❘ Carburetor setting table for the SE-R 250: ..............................................................................................46
CARBURETORSETTINGTABLE ...................................................................................................................................47
❱❘ Carburetor setting table for the SE-R 300: ..............................................................................................47
CHECKINGTHECHARGINGSYSTEM .............................................................................................................................48
❱❘ Static control values (engine off) 250 SE-R/300 SE-R ................................................................................48
❱❘ Dynamic control values ...................................................................................................................48
WIRINGDIAGRAMS ...............................................................................................................................................49
❱❘ Main harness 6517 ........................................................................................................................49
❱❘ Lighting harness 250 SE-R/300 SE-R ...................................................................................................51
❱❘ Lighting harness - Racing 250 SE-R/300 SE-R ........................................................................................52
❱❘ Wiring harness - accessories .............................................................................................................53

250-300 SE-R
4
FOREWORD
This manual is intended primarily for use by trained mechanics in a properly equipped
workshop.
The various operations require strong mechanical skills and specifi c tools to work on the
SHERCO 250 SE-R and SE-R 300 engines.
This workshop manual complements the SHERCO 250 SE-R and SE-R 300 manual.

5
ENGINETOOLLISTFORUSE
❱❘ On the 250 SE-R and 300 SE-R
Tool reference
Description
5749
Clutch block
5207
Flywheel block
2067
Swingarm tool
R467
Tool for the oscillating input shaft bearing housing
R465
Secondary shaft bearing tool
5397
Gearbox bearing output shaft tool
R446
Gearbox output shaft tool
5398
Roller bearing selection tool
5399
Left crankcase bearing tool
R469
Right crankcase bearing tool
5400
Clutch side crankshaft bearing tool
5401
Ignition side crankshaft bearing tool
5402
HK0808 needle bearing tool
(water pump, starter motor double pinion, starter motor bearing)
1968
Water pump seal tool
1821
Motor support
5206
Primary pinion block tool
2073
Spring block (selection fi ngers)
5208
Flywheel puller
R464
Crankshaft ring extractor
R453
Selector shaft bearing assembly tool
R444
Oil seal installation tool
FRANÇAIS

250-300 SE-R
6
ENGINESPECIFICATIONS
❱❘ Engine
Type
Single cylinder, 2-stroke, liquid cooled
Displacement
249,32 CC
293,14 CC
Bore/Stroke
66,4/72 mm
72/72 mm
Fuel
Unleaded gasoline with an octane rating of at least 95 with
a (2%) mix of 2-stroke oil
Cooling
Liquid with forced circulation
Ignition system
DC-CDI system with digital advance
Spark plug
NGK BR8ES/DENSO W24ESRU
Spark plug gap
0.7 mm
Piston
Forged aluminium
Engine oil
750 ml SAE 10W40
Transmission primary drive ratio
27 : 75
Transmission:
1
st
2
nd
3
rd
4
th
5
th
6
th
6 speed
14 : 32
15 : 26
19 : 27
21 : 24
23 : 22
25 : 21
Transmission final drive
14 X 49
Clutch
Hydraulically operated, multi disc in oil bath
Starter
Electric starter
Battery
12V 4Ah
Alternator
220W
❱❘ Carburetor
Type of carburator
KEIHIN PWK 36S AG
KEIHIN PWK 36S AG
Needle position
4
th
position from the top
3
rd
position from the top
Needle jet
N8RW (N84K)
N8RG (N84K)
Main jet
KEA 170 (KEA 115)
KEA 165 (KEA 115)
Pilot jet
KEP 40 (KEA38)
KEP 40 (KEA 38)
Starter jet
85 (50)
85 (50)
Air screw adjustment
1 ½ turns
1 ½ turns
Slide cut
N°7
N°7

7
CHASSISSPECIFICATIONS
❱❘ Chassis
Frame
Semi-perimeter Cr-Mo steel with an aluminium subframe
Fork
SACHS USD Série Or Ø48 mm (standard)
WP suspension USD Ø48 mm (racing)
Rear suspension
WP shock with remote cylinder and aluminium control rods
Travel Front/Rear
300/330 mm
Front brake disc
Ø 270 mm (standard), Ø 256 mm (racing)
Rear brake disc
Ø 220 mm
Disc brake wear limit
2.7 mm front and 3.6 mm rear
Front tire
90/90-21’’
Rear tire
140/80-18’’
Tire air pressure (all terrain)
0.9 bar (13 psi)
Fuel tank capacity
10.4l with1 liter of reserve (2.75 gallons / .25 gallons)
Steering angle in both directions
27.3°
Wheelbase
1480 mm (58.3 inches)
Weight
105 kg (231.5 pounds)
FRANÇAIS

250-300 SE-R
8
FACTORYSETTINGS
❱❘ Front fork
Front fork factory settings –SACHS 48mmØ USD Series
Compression
12 clicks back
Rebound
12 clicks back
Spring stiffness
4.5N/mm
Fork oil
SAE 5
Quantity of oil per leg
600 cm
3
(20.3 fluid ounces)
Oil level (with the fork compressed, and the spring
removed. Measured from the top of the fork tube)
130 mm (5.12 inches)
Front fork factory settings –WP 48mm ØUSD Series
Compression
Comfort
20 clicks back
Standard
13 clicks back
Sport
8 clicks back
Rebound
Comfort
18 clicks back
Standard
13 clicks back
Sport
10 clicks back
Preload
Comfort
4 turns
Standard
6 turns
Sport
8 turns
Spring stiffness
Rider weight: 65-75 kg (143 –165 pounds)
4.0N/mm
Rider weight: 75-85 kg (165 –187 pounds)
4.2N/mm (original)
Rider weight: 85-95 kg (187 –210 pounds)
4.4N/mm
Fork oil
SAE 4
Oil level (with the fork compressed,
and the spring removed. Measured
from the top of the fork tube)
110 mm (4.33 inches)

9
FACTORYSETTINGS
❱❘ Rear fork
Factory settings –WP rear suspension unit
Low speed Compression
Comfort
20 clicks back
Standard
15 clicks back
Sport
12 clicks back
High speed Compression
Comfort
2,5 turns back
Standard
2 turns back
Sport
1,5 turns back
Rebound damping
Comfort
15 clicks back
Standard
13 clicks back
Sport
11 clicks back
Spring stiffness
Rider weight: 65-75 kg (143 –165 pounds)
48N/mm
Rider weight: 75-85 kg (165 –187 pounds)
51N/mm (original)
Rider weight: 85-95 kg (187 –210 pounds)
54N/mm
FRANÇAIS

250-300 SE-R
10
OPERATIONSPERFORMEDWITHTHEENGINEINANDOUTOFTHEFRAME
Operations requiring engine
removal
Operations that do not require
engine removal
Crankshaft (including connecting rod)
•
Transmission - Complete
•
Crankshaft bearings
•
Transmission bearings
•
Piston
•
Cylinder
•
Cylinder head
•
Ignition
•
Starting motor gearing
•
Complete clutch
•
Water pump
•
Transmission gear selector
mechanism
•

11
REMOVING/INSTALLINGTHEENGINE
❱❘ Removing the engine
- Drain (See the owner’s manual)
• The engine oil
• The engine coolant
- Remove the seat.
- Disconnect the battery.
- Remove the fuel tank with its valves.
- Disconnect all of the wiring harnesses that are connected to the engine (starter, etc.).
- Remove the exhaust (See the owner’s manual).
- Remove the carburetor.
- Remove the chain (use the master link).
- Remove the chain guard.
- Remove the clutch slave cylinder.
- Remove the water lines connected to the engine.
- Remove the left radiator.
- Loosen all of the engine mounting bolts.
- Loosen the swing arm axle bolt.
- Remove the mounting brackets that are attached to the cylinder head and the electric motor.
- Remove the rear axle.
- Remove the swing arm axle.
- Disconnect all of the cables from the valve block.
- Remove the motor.
CAUTION
When the clutch slave cylinder is removed the piston is no longer contained. Retain the piston with a plastic tie.
CAUTION
In order to remove the engine, the swing arm pivot bolt must be removed. This allows the swing arm and the rear
wheel assembly to be separated from the bike. To insure that the bike does not fall, support it with a jack.

250-300 SE-R
12
REMOVING/INSTALLINGTHEENGINE
❱❘ Reinstalling the engine
The installation of the engine back into the frame should follow in reverse order the way it was removed. Note
the torque value of all of the mounting bolts: Engine mounting bolts: 60Nm (44 lb-ft)
Swingarm nut: 100 Nm (74 lb-ft)
Clutch save cylinder bolts: 10 Nm (7.4 lb-ft)
Cylinder head bracket bolts: 23 Nm (17 lb-ft)
- Make sure the tensioning cables are completely
relaxed.
- Adjust the top position cable n°1 on the cable
pulley and in the cable stop located on the
cylinder.
For the lower cable n°2, put it in the cable stop
without any tension.
Turn the bike ignition switch ON.
Wait until the electric motor initializes the
valves and then shuts down.
Turn the bike ignition switch OFF.
- Start adjusting the upper cable tensioner n°3 by
unscrewing the 8 nut…
…in order to obtain 10.2mm +-0.2 as shown
here.
CAUTION
Be careful when installing the engine. The cable tension of the exhaust valve control mechanism is very critical to
the proper operation of the engine. Followthese steps in order to properly adjust the cables.

13
REMOVING/INSTALLINGTHEENGINE
- This position of pulley corresponds to valves
100% closed.
You can use a wrench 10 to controle.
- Tighten the 10 nut.
- Start adjusting the lower cable tensioner by
unscrewing the 8 nut until it comes against the
sleeve stop.
CAUTION: Tighten only until the cable is not
moving anymore while pulling (WITH
STRENGTH) the sheath toward the rear of
the bike. Stop adjusting at this time.

250-300 SE-R
14
REMOVING/INSTALLINGTHEENGINE
- Tighten by 1 full turn the 8 nut (1full turn =
1mm).
- The measurement between the tensioning
cable crimping sleeve and bottom of the
cylinder sheath should be 0.5mm minimum,
1mm maximum when pulling (WITH
STRENGTH) on the cable to the rear of the
bike. If this measurement is not correct, correct
by thightening or loosening the 8 nut.
- Tighten the 10 nut.
- Lubricate, with grease for chain (in spray), the
cables on the pulley, the pulley groove and the
steel plate to prevent oxidation.
- Replace the protective rubber of the pulley, the
protective plastic cover and tighten the screw.
Finally, replace the protective rubbers on the
two tensioners.

15
DISASSEMBLYOFTHEENGINE
Refer to the exploded view in the parts catalog for the 250 SE-R / 300 SE-R
❱❘ Draining the transmission oil
- Remove the drain plugs [1] and[2],let the oil
drain.
❱❘ Removing the sprocket and the
gear selector
- Straighten the security tab [3] using a suitable
punch.
- Remove the nut and the sprocket [4].
- Remove the bolt [5] and the gear selector.
- Remove the clutch control rod.
2
1
3
4
5

250-300 SE-R
16
DISASSEMBLYOFTHEENGINE
❱❘ Removing the cylinder head,
cylinder and piston
- Remove the cylinder head mounting bolts [1]
the cylinder head and the two o-rings.
- Remove the four socket head bolts [3] and the
four washers [2] located on the base of the
cylinder.
- Remove the cylinder.
- Remove the piston pin retaining clips.
- Remove the piston pin.
- Remove the piston and the needle bearing
from the connecting rod.
- Remove the base gasket.
3
2
1

17
DISASSEMBLYOFTHEENGINE
❱❘ Removing the clutch
- Remove the waterpump cover screws and the
cover.
Remove the seal.
- Remove the clutch cover screws and the
cover.
Remove the seal.
❱❘ Removing the pressure plate and discs
- Carefully loosen all of the screws [1] on the pressure plate.
- Remove the screws, the springs and the spring cups.
1

250-300 SE-R
18
DISASSEMBLYOFTHEENGINE
- Remove the pressure plate and the discs.
- Remove the clutch release bearing assembly
[1] located in the primary shaft.
❱❘ Removing the electric starter
- Remove the 2 screws [2].
❱❘ Removing the primary drive gear
- Secure the end of the crankshaft gear with the
special tool 5206 [3].
- Loosen the fi xing nut [4] and remove the nut,
primary drive gear and the conical washer.
- Open the safety washer on the clutch hub nut
[5].
- Use special tool 5749 [6] to hold the clutch hub
and loosen the nut.
- Remove the tool.
- Remove the nut, the clutch hub and the two
needle bearings.
2
2
4
3
6
5
1

19
DISASSEMBLYOFTHEENGINE
- Remove the primary gear and spacer [1] from
the crankshaft.
❱❘ Removing the interlock mechanism
- Use a screwdriver to compress the spring on
the ratchet mechanism so that it no longer
engages the shifting drum. Remove the
selector shaft.
- Remove the retaining bolt [2] and the remove
the shifting interlock mechanism [3].
- Remove the bolt [4] and then remove the lever
along with the spring and the spacer.
CAUTION Note the pin and the seal. The
primary drive gear and the clutch hub are matched
so they can not be changed separately. They
must be replaced as a set.
CAUTION Make sure that the washer stays at
the bottom of the housing.
CAUTION Note the location of the dowel pin that
locates the interlock mechanism. The locking lever
must be removed if the case is changed.
1
3
2

250-300 SE-R
20
DISASSEMBLYOFTHEENGINE
❱❘ Removing the ignition cover
- Remove the retaining screws, and then remove
the ignition cover along with the gasket.
❱❘ Removing the electric starter double
gear and the starter drive
- Remove the three shoulder bolts [1].
- Remove the double gear retaining bracket [2].
- Remove the double gear [3] and the needle
bearing.
- Remove the starter drive [4].
3
4
2
1