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