Specifications
Chapter
1 Engine, clutch and gearbox
Refer to Chapter 7 for information relating to the
1985
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
11
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
15
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
Skirt
OD
Wear limit
Gudgeon
pin
OD
Wear limit
Gudgeon pin bore
ID
Wear limit
Air cooled, single cylinder, four stroke
56.5
mm (2.224 in)
49.5
mm (1.949 in)
124cc(7.56cuin)
9.0:1
9.2:1
Forged aluminium alloy
56.45 - 56.48 mm (2.2224 - 2.2236 in)
56.35 mm
(2.2185
in)
14.99
- 15.00
mm (0.5902 - 0.5906 in)
14.96
mm (0.5890 in)
15.00 -
15.01 mm (0.5906 - 0.5909 in)
15.04
mm
(0.5921
in)