1 Engine, clutch and gearbox
Refer to Chapter 7 for information relating to the
on Brazilian models
Contents
General description 1
Operations with the engine unit in the frame 2
Operations with engine removed 3
Method of engine/gearbox removal 4
Removing the engine/gearbox unit 5
Dismantling the engine and gearbox unit : general ... 6
Dismantling the engine and gearbox unit : removing
the cylinder head, barrel and piston 7
Dismantling the engine and gearbox unit : removing
the generator assembly 8
Dismantling the engine/gearbox unit : removing the
cam gear and shaft 9
Dismantling the engine/gearbox unit : removing the
centrifugal oil filter 10
Dismantling the engine/gearbox unit : removing the
oil pump
Dismantling the engine/gearbox unit : removing the
clutch assembly and crankshaft pinion 12
Dismantling the engine/gearbox unit : removing the
gearchange shaft and mechanism 13
Dismantling the engine/gearbox unit : removing the
end float plunger and neutral switch 14
Dismantling the engine/gearbox unit : separating the
crankcase halves
Dismantling the engine/gearbox unit : removing the
kickstart mechanism, crankshaft assembly and gearbox
components 16
Examination and renovation : general 17
Crankshaft and gearbox main bearings : removal ... 18
Examination and renovation: big-end and main
bearings 19
Examination and renovation: gudgeon pin, small
end and piston bosses 20
Examination and renovation : piston and piston rings 21
Examination and renovation : cylinder barrel 22
Cylinder head : valve removal, examination and
renovation 23
Examination and decarbonisation : cylinder head ... 24
Examination and renovation : rocker arms, adjusters and
pushrods 25
Examination and renovation : cam gear and lobe, and
cam followers 26
Examination and renovation : trochoidal oil pump ... 27
Examination and renovation : clutch and primary drive 28
Examination and renovation: gearbox components 29
Engine casings and covers : examination and repair ... 30
Engine reassembly : general 31
Engine reassembly : gear clusters and selector
mechanism reassembly and replacement 32
Engine reassembly : replacing the crankcase
components 33
Preparation of crankcase jointing surfaces : joining the
crankcase 34
Replacing the crankshaft pinion, oil pump and
gearchange mechanism 35
Replacing the clutch assembly and centrifugal oil filter 36
Replacing the camshaft, generator and left-hand casing
fittings 37
Replacing the gearbox sprocket 38
Refitting the piston, cylinder barrel, cylinder head and
rocker arms 39
Refitting the engine/gearbox unit in the frame 40
Starting and running the rebuilt engine 41
Fault diagnosis: engine 42
Fault diagnosis: clutch 43
Fault diagnosis: gearbox 44
Specifications
Engine (general)
Type
Bore
Stroke
Capacity
Compression ratio
CG125 CG125 K1, B
CG125-C, E
Piston
Type
OD
Wear limit
Gudgeon
OD
Wear limit
Gudgeon pin bore
Wear limit
Air cooled, single cylinder, four stroke
mm (2.224 in)
mm (1.949 in)
9.0:1
9.2:1
Forged aluminium alloy
56.45 - 56.48 mm (2.2224 - 2.2236 in)
56.35 mm
in)
14.99
mm (0.5902 - 0.5906 in)
mm (0.5890 in)
15.01 mm (0.5906 - 0.5909 in)
mm
in)
