CRANKCASE/CRANKSHAFT NU50· NU50M
10-0 98 Dale of Issue: NOli •• 1981e HONDA MOTOR CO., l TO.
CRANKCASE/CRANKSHAFTri/)HON'DA 10.NUSO·NUSOM
SERVICE INFORMATION 10-1
TROUBLESHOOTING 10-1
CRANKCASE SEPARATION 10-2
CRANKSHAFT REMOVAL 10-3
CRANKSHAFT INSPECTION
CRANKCASE ASSEMBLY
10-3
10-5
SERVICE INFORMATIONGENERAL- The lollow"'9 parts musll)e removed before separating the crankcase:
Engine- Mounting bracket- Genter standOil pumpReed valveKIck Slaner driven gearAlternatorCylinder head, cylinder
Page 5-2
Page 2-5Page 4·9PageS·l1.17Page 7-2Page 6-2, 3
. In addition 10 the above, remove the following parts when the left crankcase halve must be replaced:
Rear wheelFinal reduction
SPECIFICATIONS
Page 12-2Page 9·2
-.-- __._n__ . ITEM . STANDAf!!?__ (in) SERVICE LIMIT mOl (inl
CONNECTING ROD BIG END SIDE 0.60 (0.024)CLEARANCECONNECTING ROD BIG END RADIALCLEARANCE 0.05/0.002)
CRANKSHAFT RUNQUT A 0.15 (0.0061B 0.10 (O.OO4J I
TOOLS
$ped,1lCrankcase Pullerseal And Case Assembling ToolBearing Remover \
CommonAttachment. 42 x 47 mmPilot, 20 mmDriverBearing Remover HandleBearing Remover Weight
TROUBLESHOOTING
07935-1870000 or modified 07933-147000007965-148001007936-3710600
07746-001030007746-004050007749-001000007936-371010007936-3710200
Abnormal engine noise
1. Worn main journal bearing
Date of Issue: Nov., 1981© HONDA MOTOR CO., lTD.
2. Worn crankpin bearing
99
3. Worn transmission bearing
10-1
CRANKCASE SEPARAnON
CRANKCASE/CRANKSHAFT
Perform the following operations:Engine removalOil pump removalRced valve removalRear wheel removal
Remove the engine mounting bracket.RenlOve the center stand bracket.
(Page 5·2)(Page 2-5)(Page 4·91(Page 12·21
NUSO· NUSOM
•Remove the cylinder head. cylinder and piston{Page 6·2. 31.Remove the alternatOl. (Page 7·2).Remove the kick Haner driyen gear (Page 8-11, 171 .Remove the final reduction usembly (page 9-2).
,
Remove the crankcase attaching bolts.
10-2 100 Date of Issue: Noy" 1981© HONDA MOTOR CO., LTD.
HONDA.NKCASE/CRANKSHAFTCRA
RCASE 07933-147 '. ht crankC<lse asI on the ngspecial 100Attach the
shown. rankcase halves.Separate the c
CRANKSHAFT REMOVAL mnk"""I on the leftthe special toO
Attach I h crankcase.shown. kshah from the eRemove the cran
R 07935-1870000CASE PULlE
T INSPECTIONCRANKSHAF 'de de",n". rod big end $1h connectingt e
with iI feeler gauge. .
(0 024 m)060mm .SERVICE LIMIT: .
. Nov., 1981Date of Issue. TOR CO., lTD.@HONDAMO '0' 10-3
CRANKCASE/CRANKSHAFT NU50· NU50M
Measure tile connecting rod big end radial clearancea, twO points in the X and Y directions.
SERViCE LIMIT: 0.05 mm (0.002 in)
Set the crankshaft on a stand or V·blocks as shownand read funout using it dial gauge.
The actual runout is of the total indicator reading.
SERVICE LIMITS:A: O.15mmlO.006in)B: 0.10 mm 10.004 in)
A60mmr---'--60mm
B
TOOLS (Bearing Installation)
Spin the crankshah bearing by hand and check forplay. The bearing mUsl be replaced if it is noisy orhas excllssivc play.
CommonAttachment, 42)< 117 mrnPilot, 20 mmDriver
07746-001030007746-004050007749-0010000
PLAY
.-== -t PLAYI' 11'111:C ')l
- fj--- f-I
f-U-u( '2JRADIAL
AXIAL
10-4 102 Dale of Issue: Nov" 1981© HONDA MOTOR CO., LTD.
NUSO·NUSOM CRANKCASE/CRANKSHAFT
CRANKCASE ASSEMBLYWash the crankshaft in soillen! and blow dry wilhcompressed air. Check for cracks or other laulu.Remove all gasket material from the crankcasemating surfaces. Dress lInv roughness or irregutaliriesWilh an oil Slone.Apply clean cr'lgine oil to all moving and slidingsul1aces.
Install the crankshaft Into the left crankcase.
NOTElubricate 'hi! crankshah main and journalbearings with Honda 2·stroke injector oil oreQuivalent.
InSlall a new gasket and the dowel pin 10 [he crank·case m311ng surface and i1sremble Ihe crankcasehalves.Assemble the removed parts in Ihe reverse order ofremol/al (Page 10·:H.
SEAL AND CASE ASSEMBLING TOOL 07965-1480010, j
SEAL AND CASE ASSEMBLING TOOL 07965-1480010
Date of Issue: Nov" 1981<&:l HONDA MOTOR CO., lTD.
103 10-5
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