2-2
dummyheaddummyhead
SERVICE INFORMATION
SERVICE INFORMATION
MAINTENANCE STANDARDS
GX120
Unit: mm (in)
Part Item Standard Service limit
Engine Maximum speed (at no load)
3,900 ± 100 min
-1
(rpm)
–
Idle speed
1,400
+ 200
min
-1
(rpm)
–
– 150
Cylinder compression
0.49 – 0.69 MPa (5.0 – 7.0 kgf/cm
2
, 71 –
100 psi)/600 min
-1
(rpm)
–
Cylinder head Warpage – 0.10 (0.004)
Cylinder Sleeve I.D. 60.000 – 60.015 (2.3622 – 2.3628) 60.165 (2.3687)
Piston Skirt O.D. 59.965 – 59.985 (2.3608 – 2.3616) 59.845 (2.3561)
Piston-to-cylinder clearance 0.015 – 0.050 (0.0006 – 0.0020) 0.12 (0.005)
Piston pin bore I.D. 13.002 – 13.008 (0.5119 – 0.5121) 13.048 (0.5137)
Piston pin Pin O.D. 12.994 – 13.000 (0.5116 – 0.5118) 12.954 (0.5100)
Piston pin-to-piston pin bore
clearance
0.002 – 0.014 (0.0001 – 0.0006) 0.08 (0.003)
Piston rings Ring side clearance Top 0.035 – 0.070 (0.0014 – 0.0028) 0.15 (0.006)
Second 0.045 – 0.080 (0.0018 – 0.0032) 0.15 (0.006)
Ring end gap Top 0.200 – 0.350 (0.0079 – 0.0138) 1.0 (0.04)
Second 0.350 – 0.500 (0.0138 – 0.0197) 1.0 (0.04)
Oil (side rail) 0.2 – 0.7 (0.01 – 0.03) 1.0 (0.04)
Ring width Top 0.950 – 0.970 (0.0374 – 0.0382) 0.93 (0.037)
Second 0.940 – 0.960 (0.0370 – 0.0378) 0.92 (0.036)
Connecting
rod
Small end I.D. 13.005 – 13.020 (0.5120 – 0.5126) 13.07 (0.515)
Big end side clearance 0.1 – 0.7 (0.004 – 0.028) 1.1 (0.04)
Big end I.D. 26.020 – 26.033 (1.0244 – 1.0249) 26.066 (1.026)
Big end oil clearance 0.040 – 0.063 (0.0016 – 0.0025) 0.12 (0.005)
Crankshaft Crankpin O.D. 25.970 – 25.980 (1.0224 – 1.0228) 25.92 (1.020)
Crankshaft runout – 0.10 (0.004)
Cylinder barrel Camshaft journal I.D. 14.000 – 14.018 (0.5512 – 0.5519) 14.048 (0.5531)
Crankcase
cover
Camshaft journal I.D.
14.000 – 14.018 (0.5512 – 0.5519) 14.048 (0.5531)
Valves Valve clearance IN 0.15 ± 0.02 (0.006 ± 0.001) –
EX 0.20 ± 0.02 (0.008 ± 0.001) –
Valve stem O.D. IN 5.468 – 5.480 (0.2153 – 0.2157) 5.318 (0.2094)
EX 5.425 – 5.440 (0.2136 – 0.2142) 5.275 (0.2077)
Valve guide I.D. IN/EX 5.500 – 5.512 (0.2165 – 0.2170) 5.572 (0.2194)
Guide-to-stem
clearance
IN 0.020 – 0.044 (0.0008 – 0.0017) 0.10 (0.004)
EX 0.060 – 0.087 (0.0024 – 0.0034) 0.12 (0.005)
Valve guide
installation height
IN 4.8 – 5.2 (0.19 – 0.20) –
Valve seat width IN/EX 0.70 – 0.90 (0.028 – 0.035) 2.0 (0.08)
Valve spring free length 30.5 (1.20) 29.0 (1.14)
Valve spring perpendicularity – 1.5° max.
Camshaft Cam height IN 27.500 – 27.900 (1.0827 – 1.0984) 27.450 (1.0807)
EX 27.547 – 27.947 (1.0845 – 1.1003) 27.500 (1.0827)
Camshaft O.D. 13.966 – 13.984 (0.5498 – 0.5506) 13.916 (0.5479)
Carburetor Main jet BE60W A #62 –
BE99A A #60 –
BE61M A #62 –
BE99B A #62 –
Pilot screw opening BE60W A 2-1/8 turns out –
BE99A A 1-5/8 turns out –
BE61M A 2-1/8 turns out –
BE99B A 2-1/8 turns out –
Float height 13.7 (0.54) –
Spark plug Gap 0.70 – 0.80 (0.028 – 0.031) –
Spark plug cap Resistance (20°C/68°F) 7.5 – 12.5 k –
Ignition coil Air gap 0.2 – 0.6 (0.01 – 0.02) –
Primary resistance 0.6 – 0.9 –
Secondary resistance 5.6 – 6.9 k –
62Z4H000.book 2 ページ ２０１１年５月２０日 金曜日 午前１０時５分
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