Royal Enfield Bullet Instruction manual

Page Nos.
PREFACE,
PRECAUTIONS GENERAL INSTRUCTIONS -
l
ROLJTINE MAINTENANCE
-
TECHNICALSPECIFICATIONS 350cc & 500cc
6-9
DESCRIPTlON OFENGINE PARTS - 10-13
DECARBONISING
SERVICE OPERATION
- ENGINE ON FWE
SERVICE OPERATION - ENGINE - REMOVED FROM FRAME
GM BOX
FRAME REAR SUSPENSION
FRONT FORK [HYDRAULIC)
WHEELS
ADJUSTMENT OFBRAKES
TYRES - REMOVAL AND REPLACEMENT
IGNITION
AND LIGHTING SYSTEM
WIRING DLAGWS
ELECIIUCAL CONNECTION DETAILS
CARBURETTOR
SERVICE LIMITS
TROUBLE SHOOTING
TORQUE VALUE CHART
SPECIALTOOLS
101-106
METRlC CONVERSION TABLE
107

PREFACE -
We take pleasure in releasing this Maintenance Manual as a guide t
-
senice. Most of the servicing can well done by the average owner. N
diagrammatic Sketches and photo illustrattons have been introduced for better
understanding. However for anowner who feels uncertain of his ability to, undertake
-
any stripping and re-building for a major overhaul, we strongly reco
work be done by an authorised 'ENFIELD DEALER/DISTRIBUTOR
that the use of proper servicemaintenance tools andgenuine Enfield
best results.
-
Whilsteverycare is taken to ensurethat the information in this manu
no liability can be accepted by Royal Enfield or the publisher for
10s
or injury caused due to errors or omissions in the informations given.
PRECAUTIONS AND GENERAt INSTRUCTIONS
Observe the following points without fail, when dismantling and
reassembhg Motor-cycle parts.
-
Be sure to replace packings, gaskets, circlips. '0' rings and cotter pins
with new ones, for 'safe riding'.
.
-
Tightenbolts & nuts startingfrom the larger diameterones to thesmaller
diameter and from inside to outside diagonally, with specffied tightening
torque.
-
Use always genuine spares and recommended grade of oils only.
When using a torque wrench for checking, always loosen the bolt or nut
by half turn and then tighten to the specified torque. Never use torque
wrench for loosening
a bolt or nut.
L
B~.G SPARE PARTS n
When ordering spareparts foryourMotorcycleit is advisable to dealdirectwith
the Enfield official dealer/distributor, who should be able to supply most of the
parts ex-stock.
\
AlwaysquotetheEngineNumber and FrameNumber and descriptionof partrequired.
It is advisableto indicatethecolour schemeespeciallywhile orderingpartsforframe.
side panels,tank, mudguards, etc.,
/

ROUTINE MAINTENANCE
Introduction
Periodic routine maintenance is a continuous processthatcommences immediately after
the machine is used. It must
be carried out at specifiedmileage recordings, or an a calendar
basis
if the machine is not used frequently.
- -
Maintenance should be regarded as an insurance policy, to keep the machine in peak
conditionand to ensure long, trouble free service.
The various maintenance tasks are described under their respective mileage and
period.
The intervals between thevarious maintenance tasks serves only asa guide. As the machine
gets older or used under particularly adverse conditions, it would be advisable to reduce the
period between each check.
For
ease of referenceeach serviceoperation isdescribed in detailundertherelevantheading.
In orderto cuttheroutine maintenancetasks,a good selectionof generalworkshop tools
is ab~olutel~essential.
Included in the kit must be a range of m
phillips head screw drivers and pair if circlip
No specialtools arerequired forthenormalroufine maintenancetasks. Thetools contained
in thetool Mt supplied with every new machine will prove adequatefor each task, or if they are
not available,the tools found
in theaveragehousehold will usually suffice.

Adaily check of the Motorcycle is essential both from mechanical and safetyaspects. It is a
good idea to develop this checkingprocedure in a specific sequence so that It wtll ultimately
become as instinctive as actually riding the machine. Done properly,
this simple checking
sequence
will give advancedwarning of impendingmechanical failures and conditions which
may jeopardize the safetyof the rider.
- Clean the motorcycle with a clean cloth.
- Check engine oil leve1,usingthe dipstick provided in the oil tank cap. Maintain oil level
upto 'H' mark. If necessary top up ofl to the required level.
- Check proper operations of all controls viz. clutch, accelerator, brakes, aI1 lights and
horns.
- Check tyre pressure, with a pressure gauge. Cneck tyre pressure when the tyres are
cold. It is worth purchasing
a smallpocket pressure gaugewhich can be relied upon, to
give consistentreadings than garage forecourtgaugeswhich tend to be less dependable.
;; <G?i'air-.r.-*,6z7-.---.. as> G.
x*2~;<p:p:>.;:.;:2?<:2:*-.-+<q2=s3@~*.: -P---- ;~~+X*?:~T+;.E%*~~~*- ,,,; -pT3-. ?!.. -:<-n-.&$.&zg
- -. .
-;$$,~g~@;gss~~:~gon@:3@Psr*~Rear G~~+z.2~a.42.G..-c ~~~~~~~e2~z2~2~~-~~~v:L+g.~~~~~E5~+zs2~:~~~~:~~ ,136:: PSI:
o , -.-
.--
-
Check tyres forforeign materials and remove them to prevent possible punctures.
- Check for adequate fuel in the petrol tank, for thejourney planned.
- Check for proper chargingof the battery after startlng the machine.
- Check ofl levels - engine & clutch
- Check contact breaker gap and adjust if necessary
- Check and adjusttappet clearance if necessary
- Check clutch, throttle and kontbrake cables and adjust if excessive play noticed
- Lubricaterear chain
d.
*. ,*
- Adjust kont &rearbrakes
-
Check wheel rims, for excessiverunout,breakage of spokes and tyres tor cracksor cuts.
- Check condition ofbatteryand electrolyte level, and top up with distilledwater upto the
level provided.

-
- Clean,'and adjust plug gap or replace spark plug.
- Check and service contact breaker points.
-
- Check and adjust Ignition timhg.
- Check and adjust valve tappet clearance.
- - Clean airfilter.
- Clean, tune up carburettor.
- Clean fuel tap gauze.
- Clean fuel tank and fuel lines.
- Check andadjust clutch. ,
-
- Adjust front & rear brakes.
- Check front fork oil level.
- Check all elecmcalconnectionsand functionsofhead Light. trafficator,horn, speedameter.
etc.
Carry out alI the operatiommentionedfor hf monthly suvfce and check the
following:
- Changeofl-engine & clutch.
- Clean or replace ofl fflter
- Changefrontfork ofl
- Check front & rearbrake linings and replace lf necessary
- Check for play in steeringhead bearings and adjust
- Check operation of steering lock and lubricate if necessary
- Check operation of side stand and condition of sprlx.

TECHNICAL SPECIFICATIONS - BULLET - 350 CC
Engine
Single Cylinder 4 Stroke with Overhead Valve
Cubic Capacity : 346cc
Stroke : 9Omrn.
Bore-Nominal : :70rnm
Actual : 69.875 mm/2.751 in.
CompressionRatio : 7.25 : 1
compression Pressure
: 110 + 5 PSI (recommended)
Engine outpl l t : 18 BHP / 5625RPM
Torque
: 2.74kgm/2875RPM
Piston and piston rfngs:
Ring dearan ce in grooves : Dimensions for new components]
Plaln (2) : .001/.003"
Scraper : .002/.004"
Ring end gap in bore : .015/.020
Maximum rir-ggap permissible : 0.030"
Gudgeon
pin diameter : .7498/.7500'!
Crank pln diameter : 1.24875/ 1.249"
Connecthg rod small end diameter : .7505/.7507"
crankshaft:
Driving side Ball bearLng :
25 X 62 X 17 mm (63051
Roller bearing
: 25x62~17 mm (NU 305orN 305)
Timing side Roller bearing : 25x52~15mm(NU205orN205R)
CamW : .3125 in.
Valve lift : .3125in.
Valve tizuing with -012" clearance
Exhaust opens : 75" BTL)C
Exhaust closes : 35"ATDC
Inlet opens : 30" BTDC
Inlet closes : 60"ATDC
Rocker bearing inside diameter
: .625/.626" (J3irnensions for new Components]
Rocker spindle diameter
: .6235/.624"
Inlet valve stem diameter : .3425/.3430
Exhaust valve stem diameter : .3405/.3410
Vdve guide internd diameter : .3437/.3447'
Valve guide external diameter : .6270/.6275
Tappet.guide internal diameter : .3752/.3760n
Tappet guide external diameter : .7505/.7510n
~rication : Dry sump, OU: tank integral with crank case
Clutch : Wet multiplate,OiI immersed
Engine sprocket
: 25teeth
Clutch Sprocket : 56 teeth
Primary drive chain : 3/8" pitch Duplex chain.

Gear Box:
Overall gear ratios
Mainshaft ball bearings
Final drive sprocket
Rear drive chain
Brake
dnun sprocket
Carburettor
Main jet
Pilotjet
Contact Breaker [Coil igdtion):
Points gap
Timhgbefore T.D.C.
Spark plug
Spark plug gap
Condenser (Capacitor)
Suspension:
Front
Stroke
Rear
Wheel Rim Type
we Size
Wheel Bearings :
Font&Rear) .
Brakes
Front
Rear
Fuel tank
Full Tank Capacity
Reserve Capacity
Oil Capacity h Grade:
Oil Tank
Fork
Clutch
Gear box
Dimensions:
Weight Dry)
Pay load (Max)
Ground clearance
Overall length
Overall width
Saddle Height
Wheel base
Electxicals:
System
5.32, 7.26, 9.80,
& 14.80
Small
- 6303
Large
- 6206
16teeth
5/8" pitch chain
38 teeth
Mikd-W-24
90
25
:
0.14/0.16" (0.35 to 0.4 mm)
: 1/32" (0.8 mm)
:
14 mm. diameter B7HS (NGKI or equivalent
: 0.46 to 0.50 mm
: 0.18to 0.25 M.F.D.
Telescopic, hydraulic damping
155 mm
Pivoted fork with shock absorbers
WM 2- 19
3.25
X 19Front)
3.50
X 19 (Rear)
17 X 40 X 12 mm (6203)or 6203 ZZ
Mechanical,internally expandingshoe type
178
mm X 38 mm Twln Leading shoes
153
mm X 25 mm Single Leading Shoe
: 14.5litres
: 1.25litres
: 2.25 litres, SAE 20 W 50
: 200 ml. on each leg. Hydraulic oil or SAE- 10W30
: 420 ml. approximately SAE2O W 40
: 700 grams of veedol'00' grease (fortopping up use SAE-20W501
: 172Kg.
: 14cm. (140mm)
: 212cm(2120mm)
: 75 cm (750 mm)
: 85 cm. (850 mm)
: 137cm (1370mm)

TECHNICAL SPECIFICATIONS - BULLET - 500 CC
8ingle Cylinder 4 8tr~ke with werheadValve
Cubic Capaclty : 499 CC
Stroke : 90mm
Bare-Nornlnal : 84mm
Actual : 83.96/83.97 mm
CornpresstDn Ratlo : 6.5:l
Compression Pressure : 110 f 5 PSI (Recommended]
Engine output
: 22 BHP/5400 RPM
Torque
: 3.5Kgm/3000RPM
Piston and piston rlngs :
IUng clearance in pxwes : (Dimensions for new components)
matn(2) : .001/.003-
*raper : .002/.004"
Rtng end gap Ln bore : .015/.020n
Maximum rlng gap permissfble : 0.038
Gudgeonpin diameter
-. . .7498/.7500"
Crank pln dlarneter : 1.24875/1.249"
Connecflngrod small end diameter : .7505/.7507
Crankshaft :
DrMng side Ball bearLng
: 25 X 82 X 17 mm (63051
Roller bearing
: 25 X 62 X 17 mm (NU 305 or N 3051
Tlming side Wer bearJng : 25~52~15mm(NU205orN205RI
Camm : -3125in
Valve lift : .3125in.
Valve thing dth .O1T clearance
Exhaustopens : 75" BTM)
Exhaust closes : 35"ATM)
Inlet opens : 3O0BTDC
Inlet clmes : 6O0ATDc
Rocker bearing inside diameh : .625/.626" [Dimensions for new Components]
Rocker spindle diameter : .6235/.6240n
Inlet valve stem diameter : .3425/.3430m
Exhaust valve stem diameter : .3405/.341OR
Vahre gulde internal diameter : .3437/.3447' -
Valve guide external diameter : .6270/.6275
Bppet guide internal diameter : .3752/.3760"
Tappet guide external diameter : .7505/.7510"
I~bricatim : Dry sump. Oil tank integral with crank case
Clutch : Wet multlplate, Oil lmmeraed
Englne sprocket : 25 teeth
Clutch
: 56 teeth
himarydrtvechaln : 3/8"pitch Duplex chatn.

Gear b~x :
Overall gear ratios
: 5.01, 6.83.9.22 & 13.93
Overall gear ratios
: Small - 6303
: Large - 6206
Ffnal drive chain : 17 teeth
Rear drive chain : 5/BWpitchchaln
Carburettor : Mikcarb-W-28
Malnjet : 110
FUot jet : 25
Contact Breaker (Coil ignition) :
Points gap : 0.14/0.16" (0.35to 0.4 mm)
Tfming before T.D.C : 1/32" (0.8 mm)
Spark plug
: NGK BR 8 ES or equivalent
sparkplug gap : 0.46 to 0.50 mm
Condenser(Capacitor) : 0.18 to 0.25 M.F.D
Snspdon :
Front : Telescopic. Hydraulic damping
Stroke : 155 mm
Rear : Pivoted fork with shack absorbers
Wheel Bfm Type : WM2- 19
mesize : 3.25 X 19Front)
: 3.50~19(Rear)
Wheel Bearings :
Front & Rear) : 17x40x12mm~6203)or6203ZZ
Brake : Mechanical. internally expanding shoe type
Front
: 178 mm X 38 mm Twin leading shoes
Rear : 153 mm X 25 mm Single lea- shoe
Fuel tank :
Full Tank Capacity : 14.5litres
Reserve capacity
: 1.25litres
Oil Capacity & grade :
Oil tar& : 2.25 litres. SAE-20W50
Fork
: 200 ml. on each leg. Hydraulfc Oil or SAE 10W30
Clutch : 420 m]. approximately SAE-20W40
Gear Box
: 700grams of veedollOO'grease(fortoppingupuse SAE 20W50)
Mmensione :
Weight (Dry) : 168 ~g. '
Pay load (Maxl : 172 ~g.
-
Ground clearance : 14 cm (140 mm)
Overall length : 212 cm (2120mml
Overall width : 75cm (750mm)
SaddleHeight : 85 cm (850 mm)
Wheel base : 137- (1370mm)
Electrlcals :
System : 12VDC

ENGINE PARTS
1. CrankcaseD/S
2. CrankcaseT/S
3. Joint washer
28. Crank Case Stud below
Distributor 56. Washer,
OU Pipe Union
5
7. WasherOil fllterCause
-- -
29. Washer. below Distributor 58.
Oil feed & returnfilters
P
30. Nut, below dLsMbutDr
4. 011 filler car, wllar
~
59. Breather pipe
31. Stud-Frontengineplates
P
60. Breatherpipe cllp
32. Washer,Front Englne plate
6. Idler punmlndle 61. Piston
33. Nut, Ront Engine Plate
62. GudgeonIpln
7. Timing shalt mUer bearing 34.
Read engine plates
35. Washer.Rear Ensine Plate
8. Tappetguide
9. Cylinder base stud
10. ctrc1l.R
(SeeuQrl
36. Nut RearEnginePIate 65. Piston
ring (compression)
lower taper
37. Stud,CrankCaseRear Joint
38. washer. Crank Case Rsar
Joint 66. Piston
ring (compmpression)
12. Ball healing
top.chrome
39. Nut,Crank CaseRear Joint
40. Stud. Crank Case Rear Jolnt
41. Washer,Crank Case Rscu
Jolnt
67. Connectfng rod
14. Distance tube (outer)
68. Connectfng rodmtirtg bush
15. Distance tube (Inner) 69. Crankpln
16. Roller bearing
1 7. Stud,CrankCaseNeck
18. Washer.Crank CaseNeck
Stud
70. Thrustwasher
42.
Nut. CrankCaseRear Joint 71. Cmnkpln nut
72. Crankpin oU hole grub
mew
73. Crankpinnut keeper screw
74. Thrustwzsher
44. Oil Seal Retainer
P
19. Nut, Crank CaseNeck Stud
45. Nut, OU Seal Retainer
-
20. Stud CrankCaseBottom
Jolnt
46. Distributor flanae pin
75. ThingshaJt
76. Driving shaft
77. F& wheel T/S
47. Distributorjlangepin
wash&
21. Washer.CmnkCaseBottom
Joint
22. Nut. CrankCaseBottom
Joint
-
c?
50. Washer.Tappet Cover Stud 79. Lock
rim
- --
51. TappetCover
24. Washer.
Head and Cylinder
Stud
80. TIS shaftnut
52. Washer(Fibre),Tappet
Couer Stud 25. Washer. Head and CylMer
Stud 82. Enginesprocket distance
tube
53. Washer(Steel),Tappet
CowrStud
26. Nut. Head and CyUnder
SW
27. Nut. Head and Cylinder
Stud
83, Engfne sprocket 25T
54. Tappet cover nut 84. Alternator distance tube
55. Oil
pipe unlon

85. Push rod inlet
86. Push rod exhaust
88. Push rod end bottom
89. Push nxi cuplock nut
90. Pushdcup
91. Tappet
92. Culinderbarrel ioint washer
93. CqIMerbarrel
94. Cyllnder headjoint washer
95. Stud. CylMerBase
'
96. Rocker oil pipe wrnplete
l l 7. Nut (long)Rocker
Box 148. Timing pinion 20T
118. Valve 149.
Key
119. Valvespring ab, bottom 150.
ou p-p mrm
120. Valvespring. outer 151. Ollpumpdlscspring
121. Valwspring. Inner
/ 52. Sprtng end pad
122. Valwsprtng ab, top 153. Casket
011 hrmp Cowr
123. Valwsplit wllar 154. OU pump aver
124. Valve stern cap 155. OU pump cover
screw
125. Spark plug 156. Nut, Oil Clsaner Stud
126. Spark plug cap 157. Washer,
011 CleanerStud
1 2 7. H.T. Lead
158. Stud; 0[1 Cleaner
128. Decompressor
mlue
159. 011 cleaner eiement
97. Rocker Oil UnionBush 129. Washer,Decompressor 160. OU cleanerspring cap
Washer WY
161. Felt washer
98. OU union
bush 130. Washer.Decompressor
MY
162. Tht=her
99. Washer Oil Plpe banjo
Union 131. Washer(Plain), 163.
011 cleaner spring
101. Cylinderhead
102. Valve
auLde
~ ~
103. Stud Rocker Box
1 04. Stud Rocker Bearinq
l 05. Washer,Rocker Bearing
1 G6. Nut,Rocker Bearing
Decompressor My
132. Decompressor My
133. Spring. Decompressor
134. Spring Cap. Decompressor
135. Cable block
136. Cable blockspllt pin
137. Decompressor
&le
assembly
164. Washer,OU Cleaner Cap
165.011 cleaner cap
166. Washer. 011 Ckaner Cap
Nut
167. Nut. Oil Cleaner
CQD
168. OU pumr, dlsc lfeedl
169. ,011 pump dlsc (return)
170. 011 pump spindle
- --
107. Rocker, Met 138.
Timing wwr
171. Plunger Ifeedj
108. Rocker, exhaust 139. Timing wwrjotntwasher 72. (rekm
109. Rocker beating inlet 140. Distributor pinion
nut
173. ou f&plug
l 10. Rocker be&g aap, Met 141. ~lstributorplni6&
40T
174. Washer
1 11. Rocker bearing, exhaust 142. Idler
DW~ 4OT 1 75. Cork oil retainer
112. Rocker bearing cap,
exhaust 143. Idler pWnbush 1
76. Timing mwr screw
113. Gasket 144. IdlerpWn thrust washer
114. Rocker
bow, Met 145.
cam wet
115. Rocker bor exfmst
146. Cam. exhaust
177. Spring washer. Tlmlng
Coveiscrew.
116. Nut (short) Rocker Box
147. Cam bush

ENGINE
Decarbonising:
After a fewthousands of Kms. of run the carbon.build up in the engine will causegeneral
falling off in power, accompanied by increased fuel consumption and starting trouble.
Decarbonising
will normally be necessq approximately every 8,000 Kms. and this can be
carried out without removing the engine fiom the frame. The mileage between decarbonising
will vary from machine to machine depending upon the type of usage.
A machine used for
frequent shortjourneys
will need more attention than onewhich is used for fast longdistance
touring.
1. Removal of the petrol tank
Close the petrol tap. Disconnect the fuel hose from petrol tap end.
Remove the two studswhich holds the petrol
tank to the frame and pull the tank upwards.
2. Removal of the Cylinder head
Remove the engine steady eye bolt.
Disconnect the high tension lead from the spark plug. Remove rocker oil pipe.
Remove the exhaust pipe and silencer.
Remove the
air filter by undoing the bolts on the sides of the air filte; body.
Push the carburettor back clear of the studsafter removing the fudng nuts.
Remove the rocker box covers.
Remove the decompressorcable fromthe lever end of the handle bar
(LH side)
Crank the engine until both valves are closed. (Keep
in Compression stroke).
Remove the rocker
CYLINDER HEAD
arms and bearings
completely after
removingthefour
3 / 1 6".
nuts on each.
Lift outthe pushrods
both inlet
& exhaust.
Remove the six
cylinder head nuts
&
washers.
Lift the cylinderhead
off the barrel, tapping it
genly beneath the
exhaust and inlet ports
with a wooden mallet.
Do Not
tap the fins.

3. Removal of Cylinder and Piston
Slacken the two clamp nutson top of the crank-case neck
Removethe 1/4" nutabove thetappet chestand lift thebarrel
Removethe
circlipretainingthegudgeonpin onthetiming
sideof piston takingcarenot todropthe
circlipintothecrank
me.
Extract the gudgeon pin using special Tool PED 20 15
(with adaptor if necessary), so that the pin and the piston
may
be repladthe same way round, i.e., split skirt toathe
front.
REhfOVAL Of PISTON
-
During this operation put a piece of clean m.g in thetopofthe crankcase to prevent foreign matter
getting in. Finally cover the crankmwith a clean cloth to prevent ingress of dustand dirt
4. Removal of Valves
VALVE SPRING COMPRESSOR
To remove thevalves from thecylinder head,
first liftoff theend capsfrom thevalve stems. If
this has stuck, it
can be removed by a screw
driver. Using compressing tool
PED 20 18 ST
ampressthe valvespringsand remove thesplit
collars from the valve tip. Slacken back the
ampressingtools and release thesprings.
Withdrawthevalve and place itssprings,top
spring collar, bottom collar, the end cap and
split conical collars together in order that they
may
be reassembled with thevalve from which
they were removed.
If the valve will not slide easily through the
valveguide. remove any sIight burrs ontheend
of the valve stem
with a carborundum stone or
by using a fie Jeweller's file to remove any
sharpedgeorburr. If theburrsarenot removed
and
Ihe valve is forced out. the valve guide may
be damaged.

5. Decarbonising the Cylinder head - Combustion Chamber
6. Hston and Rings
If the piston rings areingood condition theycanbeput back,takingcareto fit them in their
original grooves and the same way up. If the fitlgs show bmwn or black patches or if their
gaps,aremore thanspecified senice
limits (Page 79),when inposition in thebarrel, new rings
should be fitted. The correct gap for new rings is given in the technical specifications (pages
6 13 8 ) for 350 and 500cc.Thegapshouldbe measured in theleastwdrn partof thecylinder
which
will be found atthe top or bottom of the bore.
Only For 350cc:
The original size of the cylinder bore is 2.751" (69,875rnm).If the wear at any point in the
bore exceeds .008" the cylinder should be rebored to .020" and
an oversize piston fitted. (It
shouldbe rebored to .040" &er
a further.008"Wear).Piston sizesavailableare.020and .040"
oversize.
The original side clearance between the piston rings
CRANKSHAFT BIG END BEARING
and grooves is .003". If the grooves show a wear of .005"
the piston should be replaced.
7. Big end bearing inspection
Examine the condition of ttle big end whilethe piston is
removed. About .010" - .026" end float is permissible and
it
will be possible to rock the connecting rod slightly. The
big end has a floating bush
with an original clearance of
approximately .003"However,
if a DEFINITE upanddown
play canbe felt, engine shouldbe stripped further to have
the big end renewed.

8. Valves, Valve Guides and springs
a
6- STEM CAP
spur COLLAR
sPNNC
INNER SPRING
OUTER SPRING
F
@B- spRING~~
VALVE GUIDE
Wear on thevahe stems can be seen onexamination
and ifade£inite stephas formed,thevalves should be
renewed. Before replacing the valves, they must be
ground on to their
seats, if good faces are not formed
with a reasonable amountof grinding. the seats must
be cutwith a cutter(includedangle 90') and thevalve
refaced
in a universal grinder. Do not attempt to form
good seats by an excessive amount of grinding. This
will causepocketingandrestrict theflowof gases. If a
pockethas already been formed this must be removed
by cuttlng with
a v&e seat cutter larger in diameter
than thevahre head.
Test the valve guides for
wear by trying the fit of a
new valve in them. Both valves shuld be quite free.
buttheexhaustvalve hasmore clearance (.002") than
Metvalve.
To remove the valve guides fYom the head. two
special tools are required which
can be easily made.
The htisa piece of tubewith
an internal bore ofnot
lessthan
7/8". The second is a mandrel about 4" long
made fYom
9/ 16" diameter bar with the end turned
down to
1/3" ~SSOR~Y
diameter for a
VALVE
L! lengthSupportof 1/2". the
CABLE ADJ USTINC SCREW
cylinderhead on the tube which fits over the collar of the
valve guide. Usingthemandrel. forcetheguide out ofthe
head with a hand press or by using a hammer.
To
fit a newguide, supportthehead atthe correctangle
and use a hand press and the same mandrel.
If a hand
press
is not available, the guide can be replaced using a
hammer and a mandrel, to prevent damage to the guide.
Check the length of the valve springs which are
oiighml& 2.020 and 2.095 fortheinnerandouter springs
respectively. If these have reached the specified sewice
limits, they should be renewed.
9. Decompressor
If the decompressor holds compression and operates
freely. there isno need to interferewithitexcept to remove
thecarbon fYom thehead of thevdve.
If thevalve is leaking.
it will be necessary to regrind it on its seat This can be
done without completely dismantling it. Having
disconnected the control cable from
the handle bar.
unscrew the decompressor from the cylinder head.
Compressthespringandremovethespringcap. Unscrew
theadjusting
screw andlocknut f?omthe cable block and
pull the cable sidewaysout of the block. Push the spring.

upwards and pull the cable nipple out of the body, It will now be possible to remove the cable
and nipple through the spring, leaving the decompressor body and spring detached from the
control cable.
The spring and the cap should now be replaced. The valve may be ground in by applying a
thin coatingof grinding paste on the seatof the valve andtwisting itto and froby means ofthe
cable block atits upper end and occasionally lifting the valve ffom
its seat. Do not rotate the
valve through a complete revolution before lifting, asthis
will g;oove the seat. Mergrinding,
wash thewhole assemblythoroughly in petrol, opening and shuttingthevalve while doing so.
Make surethat all traces of grinding paste have been removed.
If the paste should get into the
cylinder serious damage would be caused.
If thevalve shows a tendency to stick-up in the body butotherwise is satisfactory,
this can
be cured by washing
in petrol, though in this case it will not be necessary to disconnect the
control cable.
If the decompressor valve isbadly burnt or bent it must be replaced.
10. Re-assembly after Decarbonising
Before building up the engine, see that all parts are scrupulously clean and place them on
a clean tray, work bench or over a clean sheet of paper. While re-assembling it is advisable to
fit a new gasket between the cylinder barrel and the crankcase.
Smearclean oil over the piston and spacethering gaps. The second ring
is a taper ring and
is marked TOP on the upper surface.
WARNING: Thismark should be on topwhenfitted. Reversingtheringwill result in pumping
of oil into the cylinder and consequent smoking.
Place the piston over the connecting rod small end ensuring the split skirt is facing the
front and-insertthe gudgeon pin. Secure the gudgeon pin with the circlips. Oil the cylinder
bore andgentlypushbarrel over the piston whilekeepingthe rings compressed in theirgrooves
and seat it gently on the barrel gasket. Refit the
1/4" nut above the timing chest.
When fitting the head
again, applyjointing compound sparingly onboth sides of thegasket,
-
Replace the six nuts and tighten them progressively anddiagonally from one side to the other
to prevent distortion.
WARNING: Excess compound may block oilways.
Placethe pushrodswith the adjustable parts downwards. The shorter pushrod istheInlet.
-
Ensurevalve stemcapsarefixed onthevalve stems. Position the rockers andbearings. making
sure that the oil feed holes are at the bottom and that the caps and bases are
in line when
tightened down. Adjust the push rods after ensuring piston is
in TDC' on compression stroke.
-
The silencer could be cleaned of carbon using a hot caustic soda solution, if necessary.
NOTE: The cylinder head and base nuts should be checked agaln for tightness, after the
enginehasbeen
run longenoughto getitthoroughly warm. Tighten theclampnutsoncrankcase
finally. For torque tightening or cy. head nuts please refer torque chart on PageNo.
100
CYLINDERHEAD 350CC CYLINDER HEAD
SW CC

SERVICE OPERATION -
WITH ENGINE ON FRAME
1. Removal of the Tixning cover
&ct,,'F
First place a tray under the engine to hold the oil which will escape when the cover is
removed.
Remove the exhaust pipe and silencer. Remove ten screws from the
timing cover, taking
care not to lose the S
washers, one for each screw.
<
NOTE: When
the timing cover it is Important thatthe engine is gently
-
cranked. This will preven? damage 07 the pumpworm or the pump spindle.
ersd H /~.44w~r4
en mallet
Draw off the
timing cover, h$$& it lightly if necessary with a woo8
dlafrf",
While refitting the timing cover ensure thattheJoint wasH%r is correctly located over the ofl
holes. using a little grease(notcompound)
to hold it in position.
xw cy+
Ensurethat the corkp ug is in position in thehole in thepumpworm. If theplug is damaged
it should be renewed to ensure oil flow to the big end bearing.
NOTE: TheAlter chamber should be !Wed with clean oil before the timing cover isrefitted.
Ensure proper functioning of oil pump by checking oil flow at rocker
ripe union whenit&e
engine is running at slowspeed. Slacken the oil pipe banjo union to see theoil-flow and clamp
it again properly. Wipe the oil that has oozed out
- OIL FILTER ELEMENT IN nMlNG COVER
OIL FILTER ELEMENT