ENGINE

1. DISMANTLINGANDREASSEMBLYWITHOUTREMOVINGENGINEFROM FRAME

1.l.Pistons

. The gudgeon pin is mounted in a needle-roller bearing. Therefore do not remo-ve the pistons without using special tools to prevent .someof the needles from

droppingout and falling into the engine where they ere bound to cause seriousd8J11age and :from which they .cen be wi thdraWD only after a dismantling. The follo-

wing proce~ure is rec.ommended:A:fter having removed the cylinders, plug the holeS'thus uncovered in the

crankcase. Remove piston rings and thenthe circlipsof gudgeon pins using special

pliers. Put the S-44 gudgeon pin &xtractor and/or the S-8B gudgeon pin drift ready

to hand. Slide the S-88 insert .into the hole in the piston and then thread theS-87 press-out pin into the insert (Fig.8). Place the 3-44 extractor in position

Fig.No.8 Pressing out gudgeon pins

on the piston and insert its extensionpiece into the S-87 press-out pin. This

pin has to be located so that its land is turned toward the cylinder centrebolt.

Acting on the S-44 extractor or S-86 drift, push the S-87 press-out pin till itscollar ir flueh with the piston holefor the gudgeon pin CFig.9).

Remove the extractor end take out carefully the S-87 press-out pin. Disengage

the piston from the connectingrodsmall end and use a length of locking wire tosecure the insert remaining between the needles in the eme1l end together with the

original shims behind the needles against felling out (Fig.lO).

- 15 -

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Fig.No.9 ~es~ing out pistons

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Fig.No.lO Securing small-end bearing

- 16 -'

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Before rea88embly make aure that 811 the neaCrie ~llft'8 (2:rlJ..a: .. in: a

total amount o:t 28 :tor one c.oDD8etiDg rod) and ehi- an in pGtri.:tiG-tI.iZ1 the

~onnacting-rod 811811 end. 8-88 insert muat be inside the bearing.. Pro.eMd 7~caret'l1lly when re:titti~ the piston on to the connecting rod ~ter tIZ1l.a.drlng ti1elock wire to prevent the Shims and needle rollers tro. :talling into the ~~.Likewise take care not to mix up the pistons - the arrowmustpoint in the ~orward

direction, and the piston :torthe left-hand cylindermust bear the stampedletter

"LO.and for the righthand cylinder the letter "P". To press home the gudge~n pinsuse again the S-44 extractor with the 5-87 press-out pin or the S-86 drift.

Remember that the relieving holes of the gcdgeonpins must be turned toward the

outer side. Lock the gudgeon pins in position with the respective circlipswith

their. Slightly outward bent ends pointing away fromthe gudgeon pin. .

Before installing new pistons, make sure that. they are of the correctgrading,i.e. A, B or C, with regard to the individual cylinders.A new piston installed

into an already slightly worn cylinder can be a closer fit, for instance,piston

"B" into the cylinder "A" - see Table 3. .

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TABLE OF GUDGEONPIN BEARING ASSEMBLIES

Table 2

'1'0assure yourself that the piston skirt is perfectlY parallel with the

cylinder liner (that the piston and cy1inde are in perfect 'alignment)make the

following check before installing piston rings on the piston. Fit tentativelythe

cylinderson the pistons(withoutpietonrings) and rotate t~e crank mechanism by

. turning the dynamo rotor to see-whetherthere is an adequate clearancebetween the

cylinder liner and piston both in the piston T.D.C. and B.D.C. If the piston leansagainst one side and returns to this position after forcing it away, it is neees-

eary to remove the cylinder and.to bend carefully the connectingrodwiththe

piston to the oppoeite side. This cylinder and piston aligning ~rocedure is calledthe connecting rod angle setting.

A- 17 -

I1"'""--

Connecting rod Gudgeon pin Needle roller Clearance

red blue white

19.994+19.998 15.994+15.997 1.994+1.996 0.005-+D.016

1.993+1.995 0.007 -+D.018

blue red white

19.998+20.002 15.997+16.000 1.994+1.996 0.006-+D.017

1.993+1.995 0.008+0.019blue. blue

,..15.994+15.997 1.996+1.998 0.005+0.016

. 1.995+1.997. '0.007+0.018

white red blue

20.002+20.006 15.997+16.000 1.996+1.998 0.006+0.017

1995+1.997 0.008+0.019blue red

15.994+15.997 1.998+2.000 0.005-+D.016

1.997+1.999 0 .00'7 a.f'\ ",

yellow red red

20.006+20.010 15.997+16.000 1.998+ 2.000 0.006+0.017

1.997+1.999 0.OO8-+D.019

In the setting is correct, the piston clearance in the cylinder liner must

be equal on either side and there must be no sticking. For reboring, the cylindersmust be clampe~ to their"bearing surface to ensure the required perpendicularity~Measure every cyliI!der after reboring and determine its new grading enabling theuse of a correct piston. Graning diameters (bores) for rebored cylinders are tobe found in Table 4.

D3

0,015+0,040

OVAL

0,085';'0,115M~

MM

Table 3 - GRADING OF PISTONS

A

Only basic dimensions are given in this table because of the intricate shape ofthe pistons.

- 18 -

Dpaation D,-O.Ol D2-o.01 D.-O.Ol

:ji9 231 011 550 A 57,95 57.925 57.71L (661-090202) normal B 57,96 57.935 57.72

R 319 231 011 540C 57.97 57.945 57.73

(661-090203) "

L 319 231 011 551A 58.20 58.175 57.96

(661-090212 1st B 58.21 58.185 57.97

R 319 231 011 541 rebore C 58.22 58.195 57.98(661-090213)

L 319 231 011 552A 58.45 58.425 58.21

(661-090222). 2nd B 58.46 58.435 58.22

R 314 231 011 542 . rebore C 58.47 58.445 58.23(661-090223)

L 319 231 011 553 A 58.70 58.675 58.46(661-090232) 3rd B 58.71 58.685 58.47

R 319 231 011 543rebore C 58.72 58.695 58.48

(661-090233)

319 231 011 554 - A 58.95 58425 58.71L (661-090242) 4th B 58,96 58.935 58.72

319 231 011 544 rebore C 58.97 58.945 58.73

R (661-090243)

g

B1D3 ¥2

Table 4 -GRADINGOF CYLINDERS

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Note: .

The manufacturer ships spare (replacement) cylinders exclusively of basic(standard) dimension~. ~~mension~ ~pecified in the tab~e refer only to rebores!For various reasons 1t 18 ve~ d1fficult to rebore cy11nders to hundredths ofmiliimeter tolerances and so 1t is necessary to measure .(at several poin1;s) thediameter of the cylinder bore after reboring and to find the matching piston {ofsuitable grading) on the basis of the measurements. Do not forget to changecorrespondingly. the. cylinder grading merki~ .on the cylinder upper surface. ','

For new as well as overhauled engines (with rebored cylinders) it is possibleto use the right-hand arid left-hand cylinders of a different gradi~ (but not ofdifferent rebo.re classesi, naturally with due regard to the respect1ve gradingclasses of pistons matched with the cylinders.'Ifthe rebore is somewhere betweenthe two grading classes, for instance 58.27 mm, it is possible to use either theclass "B" or;"C" piston. With the class "B".piston, the runnung-in is quickerwhile the possibility of piston knicking in a cold engine is reduced whed usingth~ class "C~ piston. ' .

"

- 19 -

Dl + 0.01 D2 + 0.02 DJ + 0.02- 0.01 ,

Normal A 58 58 58B '58.01 58.01 58.01 '"'

C 58.02 58'.02 58.02

A 58.25 58.25 58.25

1st rebore B 58.26 58.26 58.26C 58.27 58.27 58.27

A 5850 58.50 58.502nd rebore B 58.51 58.51 58.51

" "

C 58.52 58.52 58.52...

", A 58.75 58.75 . 58 753rd rebore B 58.76 58.76 58.76

C 58.77 58.77 58.77

A 59.00 59.00 59.00

4th rebore B 59.01 59.01 59.01C' 59.02 59.02 59.02

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1. 2 ~U1',.ttor...

TIt. .'f:7. flret' to' do- before adjusting the car.burettor is to see whether theai's8! of" the' main petrol jei correspo'nds to the design (version) of the intake8i'1.uC1.r~, On-motor cyc1'e8' with a noise damping. insert in the inlet of the intakeatT-enc..-, th8" Main jet' must be of a smaller size. Che.ck the main jet size 81sowhen'inat'8lling,' s' ne.. carburettor.

if'oia. in'4&e111&o1s.

Main jet IDlingjet

Needleposition

Fast..idlingscres

Carburettor'

a:t+1. 2926 SBDb2002 .

2926-SBDb2001

2~"2-6:,SBDMb'27'83"

1/20,5--1,5

1/20,5-1,5

1/20,5..1,5

1/20,5-1,5

1/20,5..1,5

115 55

55

4th Running-in3rd aft er" .

'3rd running-in2nd after"

4th running-in3rd af'ter '!

3r(\ running-in2nd af'ter "

'3rd runni112-in2nd after if

84\ 92

115 5584""3.:.Oi'Imast:e-r

84', ,- 92 55r.

82'HbU:end'OtlDrafft&r-

98 55Xi

x R8'p"l'8eement'carburettors are' not shipped as uni ~s. If necessary, :f'it carburet-tors:, sp:e'cit'ied' in' the table with different jets.

~.): }>b:i1Irar,y.~r:ansllli'ssion

Remo.v..' the' kickst'ar.ter lever (after having turned it to the starting posi-

~:otil and" the-n 'two" acrews'. hOlding down the left-hand crankcase cover. If' the oil11-es"not' been drained before, then, put a sui table vessel under the cover and remo-

v4",";~e'" cover. by prizing of off carefully. Remove the clutch plates, unlock the.' mmainshaft nut' end' sndg the ~66 pi-lot plate into the clutch centre dresser.'"

Use' the~ "T9"'tubular: spanner to remove the M 12 nut (Fig.ll) and the "24 spanner

to' re1Qo.V8",th8"nut' of'the: primary sprocket (Fig~2). Lift out the clutch centredrum" puIJ:: 0-« the..primary sprocket using the 5-85 puJ.ler (Fig.l), and remove ittoge't1te-r.' wt'th' the;, c~ain and clutch chain wheel (toothed arum) from the shafts.

, (Fi:g..,14~".-If:' the" primary sprocket is a too tight fit on the taper, tension thepuD."er' 8S'!much 8S"pO'BBibl'e'and' tap the head of the puller bo1t. If even thisproce'dUr:'e' :ta:i:18'ito' :fr8'e' the' sprocket, heat up carefully' its ~ub with a flame tomalt it': e-xpsnd' suf'ftci'ently' for the- sprocket to be pulled off easily. -

rh: t~ JII8-uori~ o-r' C'8S'8S, it i-e possib'le to remove the clutch chain whe-elwiithl).~t'.pull1.ugl of~ th'e' primary sprocket (if the chain has already been somewhat

8tret~lted".- PU81tend' puI],; t'ti-e' alutch chain wheel several times on the mainsh~ulI'tia:. ~.. di'St'ance~ s-l:.e-eve;o-f' the- chain, wheel slides out sutf'iciently t~ be grabbedand: p:u1t1:e:d'out.. At'. a, conv.eni'ent inclinati'on of the clutch chain\Yheel, the slacke-n-e4tprl'mar.:Y'c1tstn- Clm be' pulled over- the teeth 'of the primary sprocket.

- 20 -

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Fig.No. 11

Fig.No.12

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Fig.No.l3 Ext~adtion of primary sprocket

Reaeeembly:~t the primary sprocket on the cleaned and dried cranksheft taper and thread

the shim, epacer and, provisionally, the clutch chain wheel on the gearbox main-

shaft. Apply a steel ruler to the flanks of the sprocket and clutch chain wheel

at the point of the toothing to make sure that they form a single plane, which is

important with regard to the service life of the primary transmission chain and

the noise of the primary transmission. Correct any deviations by putting steel

shims of a suitable thickness on the maindshaft between the bearing and bearing

shim of the clutch chain wheel. After having completed the parallelity check,

remove again the clutch chain wheel.

Before reinstalling the starting mechanism! check the shaft seal for condi-

tion. Install the starting mechanism with the starter shaft turned to the starting

position. Fit the sprocket and the clutch chain wheel with the primary transmis-

sion chainin position on them on to the crankshaft taper and mainshaft. Slip .the

clutch centre drum on the mainshaf't together with its lock washer. Fasten now the

clutch centre drum with the respective nut and lock the washer. 'Tighten the nut

of the primary sprocket on the crankshaft. During these operations use the S-66

pilot plate. Insert now alternately the friction and steel clutch plates while

making sure that the clutch plate dogs enter freely into ~he slote in the'clutch. '

chain wheel. When installing new clutch plates, measure first their total thickneSs

which should be between 18.25 and 19 mm for the five plates. Install the oiled

clutch release rod with disk into the mainshaft, locate the pressure plate with

springs, insert the respective washers above the springs, and then compress the

springs over the washers one after the other using a "10" spanner while slipping

lock pins above the washers.

- 22 -

Fig.No.14 Removing primary transmission

Smear with motor grease the cleaned and undamaged mating surface of the

crankcase and place thereon the undamaged, preferably new, gasket. Smear with oil

the starter shaft and reinstall the ~eft-hand crankcaee(~over. Tighten properly

its M 8 fastening screws. Refit the kickstarter leve~ and test gear shifting and

starting. '

1.4 Speedometer Drive

Remove the primary transmiss~on as described in chapter 1.3. Remove the M 6

screw from the bottom part of the engine, holding down the speedometer drive end

piece. Push the speedometer drive out of the engiqe. In the bottom part of the

left-hand crankcase half there is a boss in which the speedometer drive is secu..

ra1y heid by a grub screw. Remove this grub screw and use a ro<i (preferably an

aluminium rod) to drive the speedometer drive body out of the crankcase together

with its packing ring.

When reinstalling the speedometer drive, slip ~ new packing ring (8x16x7)

to the drive shaft so that the ring spring points inside the engine. Then use e

tube or a tubular spanner with an outside diameter of 15 mm to tap home carefully

the speedometer drive into its mounting (pushing the tube'or tubular spenner

through the hole in the crankcase) till the slot on the surface of the drive

coincides with the threaded hole for the grub screw in the crankcase.

Tighten the grub screw and secure it from working loose by a centre punch.

Then proceed with the reassembly of the primary transmission &S described in'

cha~ter 1.3... 23 ..

1.5 KickatarterReturn SDrin«

The kickatarter return spring cen be replecea with e new one without rellloYing

the clutch chain wheel (primary transmis8ion).' .

Drain the oil from the gearbox or put the motor cycle OD its ript eide afterremoving the battery. .

Remove the kicksterter lever and pu'eh theetarter eha:tt inward While turningit to the starting poei t,ion. Reaaovethe 1e:tt-handcrankcase cover, turn the etarter

shaft antic1~ckwise, and slide it outotits mounting. Withdraw the ,ietarter quaclranttogether with the sprlng.' ,

Install the new spring so that one end 01' it is sa1'e17'retainea by the pin

provided for this purpose in the craIikcase. Thread the other end into the h~le inthe quadrant and turn the quadrant so that it can snap into the oon.ct, position,i.e. withthe centre of its hole aligned with the centre 01' the hole in thestarter dog. Then push in the starter shaft- (with the riturnepring)Whil. turningit to the etarting position, i.e. c10c1qriae, in which the starting _chaniaID.holds together. . ,

This job requires a certain amount ot:" skill. A simplar thoug more time, . -

consuming procedure is the replacement q1' the apring &:tter the remo~a1 01' thecomplete primary transmission - see chapter 1.3.

1.6 Shifter Shaft with Driving Lug and Pawls

First remove the primary transmission meohanis. - aee chapter.1.3. Rotat.

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~g.~0.15 Removing shitter shaft

- 24-

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slightly the starter shaft and withdraw it together with the starting quadrantand..return spring. Remove the bracket with the clutch release mechanism (chapter1.8), drive out (upward) the pin fastening the clutch release cam on to the shaft,and lift off the cam. Insert the S-63 pawlretaining jig between the shifter gateand the pawls and push carefully the shifter shaft with the driving lug and pawlsfrom its mounting (Fig.15). .

When reassembling the mechanism rest the 5-63 pawl retaining jig on the pawlsof the driving lug. Remember that the driving lug pin must be inserted correctlybetween the return springs in the shifter gate. For further reassembly reversethe described dismantling procedure (1.6).

1.7 DynS1l1O

Re~ove the right-hand crankcase cover and disconnect cables from the dynamo.

Remove two M 6 screws ("10" spanner) holding do?'D the at ator, and slide out "the

stator. After lifting it off, it is recommended to remove fasteners of the carbonbrushes and to withdraw the brushes from their guides to prevent their being

damaged during reassembly. R&mOvethe M 6 screwhol~ing down the rotor andliftoff the cam with the aid of a screwdriver inserted under it. Use the S-48 rotor

puller to pull the rotor off the shaft (Fig.16).

Put the rotor into thestator, and put away the dynamo in a safe place where

it cannot get damaged or, i~ necessary, hand it over for repair.

Reverse the described procedure when reinstalling the dynamo. First reinstall

the rotor including the cam and then refit the stator. Do not tighten the stator

screws with a too great force (the recommended torque is 0.6 kpm) es this would

Fig.No.16 Pulling dynamo rotor off the shaft

- 25 ~

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result in distorting the contact-breaker base plate. Slip brushes into the bruehholder minding their correct position. If the brushes are shorter than 8 DID,

replace theillri th ne.. ones, Lock the brushes in posi.tion using the respectivespring tasteners (clips). Saturate the cam wiper felt with grease but be careful

not to 8pp1;rtoo much gre~se which could then ap1ash or flow down between thecontact-bre.er points.Final1y adjust the ignition advance and the contact-breaker

point gap. Tbis adjustment i8 described' in a separate chapte~.

1.8 Dec1utchiqp: Meohanism

Iiemove the brake pedal or 8crew ott the winged nut of the ~ear brake cable.Remove the right-hand cover of the engine (crankcase), loosen the screw tastening

, , I

thebowden cable in tbec1_, and pull out the cable. Use "10" spanner to removethree screW,s attaching the bracket of' the dec1utQhing mechanism to the crarikca:seright-hand side, and take off the bracket.

. Reverse thi;sprocedure when reinstalling the declutching mechanism.

1.9SecondeJ'Y Spl'ocket

Remove the dec1utohing mechanism - see chapter 1.8. Detaoh the £ront sleevesof the. rubber chain guards snd remove the outer cover of' the secondary sprocket(Fig.17).

Fig.Ho.17 Removing se COn4a.ry sprocket cover, '

Unlock the lock washer anI! 8Crew ott the... nut u8ilig the S-68 tUbular wrench.,H~wslide the secondary sp'l'Ooket with the slackened chain end inIu~r cover out otits mo"unting. It is not necessary to disconnect the chain.

Reverse this procedure when reinstalling the secondary sprocket.WarningI ' '

Proceed ver7 carefully when reinstalling the secondary sprocket. NQresistan-ce IDUstbe felt when s1ipping it on the splines. When driving' it home forcibly

you run the riek of moving thebem:ing into the crankcase in spi 1;e ot it8b.~ngprotected against" normal stressing by a thrust shim. Even 8 slight pushing of' the

. :bearinginto the crankcase is bound to result in a 8erio~s damage to the shinertOMS and gears ~t the gearbox.

- 26 -

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2. CRANKCASE DISMANTLING AND REASSEMBLY

(with engine removed from frame)

2.1 Removing Engine from Frame

After having removed the seat~ disconnect the battery fuse and pull cables

off the spark plugs. Shut off the fuel cock, free the front part of the fuel tank.

by pushing out the hold-down springand 8wir~ up the fuel tank. Screw.off the

carburettor cap and withdraw the throttle cable with the slidir~ throttle valve.

Remove the nuts (hollow screws) of the exhaust pipes (elbows), swing the exhaust

pipes out of the way, and remove the M 8 screw fastening the front part of the

left-hand exhaust silence..:.'.Then loosen t.wo M 8 screws of the left-hand exhaust

silencer rear bracket to facilitate t~e removal of the footrests ~ie bolt used

also BS the engine clamping bolt. Remove the grub screw of the speedometer drive

at the engine and withdraw the ~exible shaft from the engine. Remove the right-

hand crankcase cover and disconnect the.leads from the dynamo. Remove the dynamo

- see chapter 1.7. Disconnect the clutch cable from the hand-controlled clutch

release mechanism snd remove the bracket of the declutching mechanism. After

having detached the front sleeves of the rubber chain guards remove the outer

cover of the secondary sprocket and unlock the sprocket nut. Slecken the rear

wheel spindle and chain tensioners, and move the real'wheel in the forward direc-

tion as far as it will go. Using the S-68 tubular wrench screw off the sprocket

nut. Now that the chain is slack, it is possible to withdraw the secondary

sprockp+ with the chain and inner cover from its ~ounting without disconnectingthe chain. Disconnebt the lead (cable) from the neutral terminal (disconnect the

connector on latest models). Remove all 8~rews and bolts holding the engine in

position i.nthe frame. Standing on the left-hand side of the machine, hold the

engine bYJ~he right-hand cyli.nder at the exhaust port with the left hand and bythe kickst'arter lever with the right hand. I,ift the front end of the engine as

high as possible and pull it leftward out of the frame by its .rear end. Be careful

not to damage the surface finish of the machine.

When reinstalling the engine into the frame, tighten first the rear bolts

and then the screws holding down the front .end of the engine. Fill the gearbox

with oil, adjust the clutch, and tension the secondary transmission chain.

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2.2 Basic Dismantlin~

Clamp the front end of the engine into

access to the engine left-hand side. Remove.

mission gear, cylinder heads, cylinder,andRemove the thirteen M 6 screws bolting

and remove the crankcase from the vice.

the jaws of a vice so as to have

tl,ecarburettor, the primary trans-pistons.

together both halves of the crankcase

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2.3 Splitting the Engine

Using the 8-64 drift drive the front centre bush and the rear guide pin from

the left-hand side of the crankcase into its right-hand side (Fig.18).

Screw the 5-62 separating press into the M 6 threads in the crankcase (for

fastening th~ dynamo stator) and pull uniformly the right-i!sndhalf of the crank-

case off the. bearings of the crankshaft mechanism with the connecting rod in the

top position to enable ita passing through the centre cutout of the crankcase

(Fig.19).

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If' the right-hend crankcase half' tends to jam during pulling off', taplightly its. rear part (from the space of the carburettor) to assists the unit'ormpulling off'. As soon es there is a sufficient gap between the two crankcasehalves withdrew the centre insert from between the cylinders to make way for the

passage of the connect~~~ rod. Then complete the splitting ot' the ingine(B~paration of the halves) and lift off the right-hand halt'.

- 28 -

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Fig.No. 19

.. - 29-

. 2.4 Gearbox, Gear Shi~tin~ Mechanism, Crank Mechanisa

In this stage of engine dismantling it is po8sible to carry out repairs ~f

the gearbox and gear shifting mechanism without pressing the crank mechanism cut

of the other hal~ of the crankcase.

For,a thorough insp')ction of the gearbow remove the ehifter

shifter forks, the layshaft, the gears, end use a so~t mallet to

out of its bearing. .

If it is necessary to remove also the shifter gata (incorrect ~ction or

when a regrinding of the crankcase half is indicated) remove the four centre-

punch secured screws end turn the gate to a position convenient tOr its withdraw-

ing. When intending to remove also the crank mecha~i8m for inspection orrepeir,

Bchrew the 8-62 separator by means of two M 8 screws into the threaded holes for

schrews of the left-hand crankcase cover and prese the crank mechanism out of the

left-hand cr~nkc8se half, again with the left-hand connecting rod in its top

position (Fig.20). If bronze bUsh~B of the 1eyshaft are worn or sticking and they

fork rod, the

tap the ma~8baft

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Fig.No.20 Pressing crank mechanism out of.crankcaae left-hand helf

have to be replaced, drive them with the drift inside the crankcase.

To facilitate replacement of the bushes remove the speedometer drive from

the crankcase lef.t-hand half - see chapter 1.4. Prees new bushes into the crank-

case heated up to a temperature of 80 to 1000C snd then ream them to diameters

specified in Table 5.

In the case the bush has been spinnin~( slipping) in the crankcase bore _ith

the rotating shaft, it is necessary to use sn oversize bush snd ream the bore in

the crankcase to the diameter speoified in Table 6.

When installing the right-hand bush mind the correct position of the oil hole

and oheck the through hole for clear passage after having presses in the bush. .

- 30 -

'~

Do not forget to clean thoroughly the oil hole 2nd insides of the new bushes

after their reeming.

Dismantling and reaseembly of the crank mechanism itself are described in

8 6eparate chapter.

Table 6

2.5 Flatness Check of Crankcase Halves Matir~ Surfaces

After having removed the old sealing compound from the meting surface andafter degreesing the whole crankcase inspectthe mating surfac~e ca~efully,andif' they are uneven, grind them on a lapping plate. A perfect flatness of the m2-ting surfacesis importantfor preventinga leakage of oil between the crankcase

halves. After grinding clean both crankcase hal~es ef grindi~ (laDDing)paste.Reinstall the shifter gate into the left-hand half, tighten firmly its M 5 fs£'.'-

tening screws, and lock the screws in position b;y centre punching.

2.6 Rene~ing of Bearings snd Pac~ing Rin~s

If it is necessary to rapiace worn or noisy besriI~s with new on&sl disreentle

first th$:crankcase and then use circlip pliers to remove the circlip holding thepacking ring in position.Hest up the cre.nkC8se to a temperature somewhere between60 and 80°C and use the S-71 bearing ext.ractor to c.rive out the bearing in the

directicn inside the crankcase. Thendrive the packing ring from the inner side

of the crankcase in the outward direction using the 8-72 packing ring installer.

Proceed in a similar manner when driving out meinshaft bearings. After having

removed the circlip and the.retaining shim. drive the bearing inward using a tube

with a diameter equalling the outside diameter of the bearing. For driving out the

bearing of the gear with hub follow again the same procedure. All bearings and

bushes have to be installed into crankcase halves heated up tu 8O-l20oC (prefe-

rably in an. .electric oven). Main (crankcshaft) beerings should be driven in fromthe inside flush with" the inner side of the crankcase by meens of theS-72 insttll-

le1', snd the mainshaft bearing and the bearing of the gear with hub as far as tothe previously installed circlip. Reinstall the packing rings only after having

reconnected both ?rankcasehalves. After installingthe mainshaft bearings,lockthem in position with th~ r~spective shims to prevent their displacement.

2.6.1 Renewing of Packin~ Rin~e

When comtempleting a replacement of only the packing rings, it is not nacee-

88ry to remove the engine from the frame. Juat remove the primary transmission

gear (1.3), the dynamo (1.7), or the secondary sprocket (1.9).

- 31 ~

Jii

HOLESFORLAYSHAFTBUSHESDJ CRANKCASE

.Dia. 17 U 8 - 0.633

- - 0.060

BUSHOUTSIDEDIAMETER 17 + 0.011

+ 0.016 + groovingBUSH INSIDE DIAMETER 14 H 8 + 0.027

+ 0.000

OVERSIZE BUSHES HAVE THE OUTSIDE DI}TER + 0.1