Royal Enfield 350 BULLET 1989 User manual

WORKSHOP MANUAL BULLET
Page 1
WORKSHOP
MAINTENANCE MANUAL
FOR THE
Enfield
India
350 BULLET upto 1989
MAN 15
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WORKSHOP MANUAL BULLET
Page 2
INDEX
Page Nos.
PREFACE, PRECAUTIONS & GENERAL INSTRUCTIONS - 2
ROUTINE MAINTENANCE - 3-5
TECHNICAL SPECIFICATIONS - 6-7
DESCRIPTION OF ENGINE PARTS - 8-10
DECARBONISING - 11-15
SERVICE OPERATION - ENGINE IN FRAME - 17-26
SERVICE OPERATION –ENGINE –REMOVED FROM FRAME - 27-30
GEAR BOX - 31-35
LUBRICATION SYSTEM - 37-39
FRAME REAR SUSPENSION - 41-42
FRONT FORK (HYDRAULIC) - 43-46
WHEELS - 47-58
TYRES - REMOVAL AND REPLACEMENT - 56-58
IGNITION AND LIGHTING SYSTEM - 59-67
CARBURETTER, VILLIERS - 68-71
CARBURETTER, BING - 73-75
CARBURETTER, MIK-CARB - 77-80
TROUBLE SHOOTING - 81-101
TORQUE VALUE CHART - 103
SPECIAL TOOLS - 105-110
METRIC CONVERSION TABLE - 111
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Page 3
PREFACE
We take pleasure in releasing this Maintenance Manual as a guide to good service. Most
of the servicing can be well done by the average owner. Numerous diagrammatic sketches and
photo illustrations have been introduced for better understanding. However for an owner who
feels uncertain of his ability to, undertake any stripping and re-building for a major overhaul,
we strongly recommend that the work be done by an authorised ‘ENFIELD
DEALER/DISTRIBUTOR. Needless to mention that the use of proper service maintenance
tools and genuine Enfield spares will ensure best results.
Whilst every care is taken to ensure that the information in this manual is correct, no
liability can be accepted by Royal Enfield or the publisher for loss, damage or injury caused
due to errors or omissions in the information given.
PRECAUTIONS AND GENERAL INSTRUCTIONS
Observe the following points without fail, when dismantling and reassembling Motor-
cycle parts.
•Be sure to replace packings, gaskets, circlips, ‘0’ rings and cotter pins with new
ones, for ‘safe riding’.
•Tighten bolts & nuts starting from the larger diameter ones to the smaller
diameter and from inside to outside diagonally, with specified tightening torque
•Always use 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.
BUYING SPARE PARTS
When ordering spare parts for your Motorcycle it is advisable to deal direct with the
Enfield official dealer/distributor, who should be able to supply most of the parts ex-stock.
Always quote the Engine Number and Frame Number and description of part required.
It is advisable to indicate the colour scheme especially while ordering parts for frame, side
panels, tank, mudguards, etc.
ALWAYS USE GENUINE “ENFIELD” SPARES
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ROUTINE MAINTENANCE
Introduction
Periodic routine maintenance is a continuous process that commences immediately after the
machine is used. It must be carried out at specified mileage recordings, or a calendar basis if
the machine is not used frequently.
Maintenance should be regarded as an insurance policy, to keep the machine in peak condition
and to ensure long, trouble free service.
The various maintenance tasks are described under their respective mileage and period. The
intervals between the various maintenance tasks serves only as a 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 reference each service operation is described in detail under the relevant heading.
In order to carryout the routine maintenance tasks, a good selection of general workshop tools
is absolutely essential.
Included in the kit must be a range of metric ring or combination spanners, a selection of
phillips head screw drivers and pair of circlip pliers.
No special tools are required for the normal routine maintenance tasks. The tools contained in
the tool kit supplied with every new machine will prove adequate for each task, or if they are
not available, the tools found in the average household will usually suffice.
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Daily
A daily check of the Motorcycle is essential both from mechanical and safety aspects. It is a good
idea to develop this checking procedure in a specific sequence so that it will ultimately become as
instinctive as actually riding the machine. Done properly, this simple checking sequence will give
advanced warning of impending mechanical failures and conditions which may jeopardize the safety
of the rider.
-Clean the motorcycle with a clean cloth.
-Check engine oil level,using the dipstick provided in the oil tank cap: Maintain oil level upto
'H' mark. If necessary top up oil to the required level.
-Check proper operations of all controls viz. clutch, accelerator, brakes, all lights and horns.
-Check tyre pressure, with a pressure gauge. Check tyre pressure when the tyres are cold. It is
worth purchasing a small pocket pressure gauge which can be relied upon, to give consistent
readings than garage forecourt gauges which tend to be less dependable.
-Tyre Pressure Front: 32 PSI - Rear: 36 PSI.
-Check tyres for foreign materials and remove them to prevent possible punctures.
-Check for adequate fuel in the petrol tank, for the journey planned.
-Check for proper charging of the battery after starting the machine.
Monthly - 300 Miles/500 Kms
-Check oil levels - engine & clutch
-
-Check contact breaker gap and adjust if necessary
-
-Check and adjust tappet clearance if necessary
-
-Check clutch, throttle and front brake cables and adjust if excessive play noticed
-
-Lubricate rear chain
-
-Adjust front & rear brakes
-
-Check wheel rims, for excessive runout, breakage of spokes and tyres for cracks or cuts.
-
- Check condition of battery and electrolyte level, and top up with distilled water up to the
level provided.
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Tri monthly –3000 miles/5000 kms
-Clean, and adjust plug gap or replace spark plug.
-Check and service contact breaker points.
-Check and adjust ignition timing.
-Check and adjust valve tappet clearance.
-Clean airfilter.
-Clean, tune up carburettor.
-Clean fuel tap gauze.
-Clean fuel tank and fuel lines.
-Check and adjust clutch.
-Adjust front & rear brakes
-Check front fork oil level.
-Check all electrical connections and functions of head light, trafficator, horn,
speedometer, etc.
Six monthly –6000 miles/10,000 kms
Carry out all the operations mentioned for Tri monthly service and check the following:
-Change oil-engine & clutch.
-Clean or replace oil filter
-Change front fork oil
-Check front & rear brake linings and replace if necessary
-Check for play in steering head bearings and adjust
-Check operation of steering lock and lubricate if necessary
-Check operation of side stand and condition of spring.
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TECHNICAL SPECIFICATIONS - BULLET - 350 CC
Engine
Single Cylinder 4 Stroke with Overhead Valves
346 CC
90 mm.
70 mm
69.875mm or 2.751 in.
7.25: 1
110 ± 5 PSI (recommended)
18 BHP / 5625 RPM
2.74 kgm/2875 RPM
(Dimensions for new components)
.001/.003"
.002/.004"
.015/.020"
0.030"
.7498/.7500"
1.24875/1.249"
.7505/.7507"
25 x 62 x 17 mm (6305)
25 x 62 x 17 mm (NU 305 or N 305)
25 x 52 x 15 mm (NU205 or N 205R)
.3125 in.
.3125 in.
75° BTDC
35° ATDC
30° BTDC
60° ATDC
.625/.626" (Dimensions for new Components)
.6235/.624"
.3425/.3430"
.3405/.3410"
.3437/.3447"
.6270/.6275"
.3752/.3760"
.7505/.7510"
Dry sump, Oil tank integral with crank case
Wet multiplate, oil immersed
25 teeth
56 teeth
3/8" pitch Duplex chain.
Cubic Capacity - - -
Stroke - - - -
Bore-Nominal - - - -
Actual - - - -
Compression Ratio - - -
Compression Pressure- -
Engine output - - - -
Torque - - - -
Piston and piston rings:
Ring clearance in grooves - -
Plain (2) - - - -
Scraper - - - -
Ring end gap in bore - - -
Maximum ring gap permissible -
Gudgeon pin diameter- - -
Crank pin diameter - - -
Connecting rod small end diameter-
Crankshaft:
Driving side Ball bearing - -
Roller bearing - - - -
Timing side Roller bearing - -
Cam lift - - - -
Valve lift - - - -
Valve timing with .012" clearance
Exhaust opens - - - -
Exhaust closes - - - -
Inlet opens - - - -
Inlet closes - - - -
Rocker bearing inside diameter -
Rocker spindle diameter - -
Inlet valve stem diameter - -
Exhaust valve stem diameter -
Valve guide internal diameter -
Valve guide external diameter -
Tappet guide internal diameter -
Tappet guide external diameter -
Lubrication - - - -
Clutch - - - -
Engine sprocket - - -
Clutch Sprocket - - -
Primary drive chain - - -
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GearBox:
Overall gear ratios - - -
Mainshaft ball bearings - -
Final drive sprocket - - -
Rear drive chain - - -
Brake drum sprocket - - -
Carburettor - - - -
Main jet - - - -
Pilot jet - - - -
Contact Breaker (Coil ignition):
Points gap - - - -
Timing before T.D.C.- - -
Spark plug - - - -
Spark plug gap- - - -
Condenser (Capacitor) - -
Suspension:
Front - - - -
Stroke - - - -
Rear - - - -
Wheel Rim Type - - -
Tyre Size - - - -
Wheel Bearings
(Front & Rear)- - - -
Brakes - - - -
Front - - - -
Rear - - - -
Fuel tank:
Full Tank Capacity - - -
Reserve Capacity - - -
Oil Capacity & Grade:
Oil Tank - - - -
Fork - - - -
Clutch - - - -
Gear box - - - -
Dimensions:
Weight (Dry) - - - -
Pay load (Max) - - -
Ground clearance - - -
Overall length - - - -
Overall width - - - -
Saddle Height - - - -
Wheel base - - - -
Electricals:
System - - - -
5.32, 7.26, 9.80, & 14.80
Small - 6303
Large - 6206
16 teeth
5/8" x 94 pitch chain
38 teeth
Mikcarb-VM-24
90
25
0.14/0.16" (0.35 to 0.4mm)
1/32" (0.8 mm) retarded
14 mm. diameter B7HS (NGK) or equivalent
0.46 to 0.50mm
0.18 to 0.25 M.F.D.
Telescopic, hydraulic damping
155mm
Pivoted fork with shock absorbers
WM 2- 19
3.25 x 19 (Front)
3.50 x 19 (Rear)
17 x 40 x 12 mm (6203) or 6203 ZZ
Mechanical, internally expanding shoe type
178 mm x 38 mm Twin leading shoes
153 mm x 25 mm Single Leading Shoe
14.5 litres
1.25 litres
2.25 litres, SAE 20W50
200 ml. on each leg. Hydraulic oil or SAE 10W30
420 ml. approximately SAE 20W40
700 grams of veedol '00' grease (for topping up use SAE 20W50)
163Kg.
172Kg.
14 cm. (140mm)
212 cm (2120mm)
75 cm (750mm)
85 cm. (850mm)
137 cm (1370mm)
6V DC Early Models, 12V DC Later models
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ENGINE PARTS
1. Crankcase D/S
2. Crankcase T/S
3. Joint washer
4. Oil filler cap collar
5. Cam spindle
6. Idler pinion spindle
7. Timing shaft roller bearing
8. Tappet guide
9. Cylinder base stud
10. Circlip (Seegar)
11. Oil seal
12 Ball bearing
13. Circlip (Seegar)
14. Distance tube (outer)
15. Distance tube (inner)
16. Roller bearing
17. Stud, Crank Case Neck
18. Washer, Crank Case Neck
Stud
19. Nut, Crank Case Neck Stud
20. Stud Crank Case Bottom
Joint
21. Washer, Crank Case Bottom
Joint
22. Nut, Crank Case Bottom Joint
23. Head & Cylinder stud
24. Washer, Head and Cylinder
Stud
25 Washer, Head stud
26. Nut, Head and Cylinder Stud
27. Nut, Head and Cylinder
Stud
28. Crank Case Stud, below
Distributor
29. Washer, below Distributor
30. Nut, below Distributor
31. Stud -Front engine plates
32 Washer, Front Engine plate
33. Nut Front Engine Plate
34. Rear engine plates
35. Washer, Rear Engine Plate
36. Nut, Rear Engine Plate
37 Stud, Crank Case Rear Joint
38. Washer, Crank Case Rear
Joint
39. Nut, Crank Case Rear Joint
40. Stud, Crank Case Rear Joint
41. Washer, Crank Case Rear
Joint
42 Nut, Crank Case Rear Joint
43. Stud-Chaincase attachment
44. Oil Seal Retainer
45. Nut, Oil Seal Retainer
46. Distributor flange pin
47. Distributor flange pin
Washer
48. Oil filler cap
49. Tappet cover stud
50. Washer, Tappet Cover Stud
51. Tappet Cover
52. Washer (Fibre), Tappet Cover
Stud
53. Washer (Steel), Tappet
Cover Stud
54. Tappet cover nut
55. Oil pipe union
56. Washer, Oil Pipe Union
57. Washer Oil filter gauze
58. Oil feed & return filters
59. Breather pipe
60. Breather pipe clip
61. Piston
62. Gudgeon pin
63. Circlip
64. Piston ring (scraper)
65. Piston ring (compression)
lower taper
66. Piston ring (compression)
top, chrome
67. Connecting rod
68. Connecting rod floating
bush
69. Crank pin
70. Thrust washer
71. Crank pin nut
72. Crank pin oil hole grub
screw
73. Crank pin nut keeper screw
74. Thrust washer
75. Timing shaft
76. Driving shaft
77. Fly wheel T/S
78. Fly wheel D/S
79. Lock ring
80. T/S shaft nut
81. Lock ring screw
82. Engine sprocket distance
tube
83. Engine sprocket 25T
84. Alternator distance tube
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85. Push rod inlet
86. Push rod, exhaust
87. Push rod end, top
88. Push rod end, bottom
89. Push rod cup lock nut
90. Push rod cup
91. Tappet
92. Cylinder barrel joint
washer
93. Cylinder barrel
94. Cylinder head joint washer
95. Stud, Cylinder Base
96. Rocker oil pipe complete
91 Rocker Oil Union Bush
Washer
98. 0i1 union bush
99. Washer Oil Pipe banjo
Union
100. Oil pipe banjo
101. Cylinder head
102. Valve guide
103. Stud, Rocker Box
104. Stud, Rocker Bearing
105. Washer, Rocker Bearing
106. Nut, Rocker Bearing
101 Rocker, Inlet
108. Rocker, exhaust
109. Rocker bearing inlet
110. Rocker bearing cap Inlet
111. Rocker bearing, exhaust
112. Rocker bearing cap,
exhaust
113. Gasket
114. Rocker box, inlet
115. Rocker box, exhaust
116. Nut (short) Rocker Box
117. Nut (long) Rocker Box
118. Valve
119. Valve spring collar, bottom
120. Valve spring, outer
121. Valve spring, Inner
122. Valve spring collar, top
123. Valve split collar
124. Valve stem cap
125. Sparkplug
126. Sparkplug cap
127. H.T. Lead
128. Decompressor valve
129. Washer, Decompressor
body
130. Washer, Decompressor
body
131. Washer (Plain), Decompressor
body
132. Decompressor body
133. Spring, Decompressor
134. Spring Cap, Decompressor
135. Cable block
136. Cable block split pin
137. Decompressor cable assembly
138. Timing cover
139. Timing cover joint washer
140. Distributor pinion nut
141. Distributor pinion 40T
142. Idler pinion 40T
143. Idler pinion bush
144. Idler pinion thrust washer
145. Cam, inlet
146. Cam, exhaust
147. Cam bush
148. Timing pinion 20T
149. Key
150. Oil pump worm
151. Oil pump disc spring
152 Spring end pad
153. Gasket Oil Pump Cover
154. Oil pump cover
155. Oil pump cover screw
156. Nut, Oil Cleaner Stud
151 Washer, Oil Cleaner Stud
158. Stud, Oil Cleaner
159. Oil cleaner element
160. 0i1 cleaner spring cap
161. Felt washer
162. Thrust washer
163. Oil cleaner spring
164. Washer, 0i1 Cleaner Cap
165. Oil cleaner cap
166. Washer, Oil Cleaner Cap
Nut
167. Nut, Oil Cleaner Cap
168. Oil pump disc (feed)
169. Oil pump disc (return)
170. Oil pump spindle
171. Plunger (feed)
172. Plunger (return)
173. Oil feed plug
174. Washer
175. Cork oil retainer
176. Timing cover screw
177. Spring Washer, Timing
Cover Screw
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ENGINE
Decarbonising:
After a few thousands of Kms. of run the carbon build up in the engine will cause general falling
off in power, accompanied by increased fuel consumption and starting trouble. Decarbonising will
normally be necessary approximately every 8,000 Kms. and this can be carried out without removing
the engine from the frame. The mileage between decarbonising will vary from machine to machine
depending upon the type of usage. A machine used for frequent short journeys will need more
attention than one which is used for fast long distance touring.
1. Removal of the petrol tank
Close the petrol tap. Disconnect the fuel hose from petrol tap end.
Remove the two studs which hold 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 filter body.
Push the carburettor back clear of the studs after removing the fixing nuts.
Remove the rocker box covers.
Remove the decompressor cable from the lever end of the handle bar (LH side)
Crank the engine until both valves are closed. (Keep in Compression stroke).
CYLINDER HEAD
Remove the rocker
arms and bearings
completely after
removing the four 3/16"
nuts on each.
Lift out the pushrods
both inlet & exhaust.
Remove the six
cylinder head nuts &
washers.
Lift the cylinder head
off the barrel, tapping it
gently beneath the exhaust
and inlet ports with a
wooden mallet. Do not tap
the fins.
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REMOVAL OF PISTON
3. Removal of Cylinder and Piston
Slacken the two clamp nuts on top of the crankcase neck.
Remove the 1/4" nut above the tappet chest and lift the barrel
Remove the circlip retaining the gudgeon pin on the timing side of
piston taking care not to drop the circlip into the crankcase.
Extract the gudgeon pin using special Tool 2015 (with adaptor if
necessary), so that the pin and the piston may be replaced the same
way round, i.e., split skirt to the front.
During this operation put a piece of clean rag in the top of the crankcase to prevent foreign matter
getting in. Finally cover the crankcase with a clean cloth to prevent ingress of dust and dirt.
4. Removal of Valves
To remove the valves from the cylinder head,
first lift off the end caps from the valve stems. If
this has stuck, it can be removed by a screwdriver.
Using compressing tool 2018 compress the valve
springs and remove the split collars from the
valve tip. Slacken back the compressing tools and
release the springs.
Withdraw the valve and place its springs, top
spring collar, bottom collar, the end cap and split
conical collars together in order that they may be
reassembled with the valve from which they were
removed.
If the valve will not slide easily through the
valve guide, remove any slight burrs on the end of
the valve stem with a carborundum stone or by
using a fine Jeweler’s file to remove any sharp
edge or burr. If the burrs are not removed and the
valve is forced out, the valve guide may be
damaged.
VALVE SPRING COMPRESSOR
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6. Piston and Rings
If the piston rings are in good condition they can be put back, taking care to fit them in their
original grooves and the same way up. If the rings show brown or black patches or if their gaps, are
more than specified service limits, when in position in the barrel, new rings should be fitted. The
correct gap for new rings is given in the technical specifications. The gap should be measured in the
least worn part of the cylinder which will be found at the top or bottom of the bore.
The original size of the cylinder bore is 2.751" (69:875mm). If the wear at any point in the bore
exceeds .008" the cylinder should be rebored to .020" and an oversize piston fitted. (It should be
rebored to .040" after a further. 008" wear). Piston sizes available are .020" and .040" oversize.
The original side clearance between the piston rings 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 the big end while the piston is
removed. About .010" - .020" 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 up and down play can be felt,
engine should be stripped further to have the big end renewed.
CRANKSHAFT BIG END BEARING
Remove carbon from the valves,
ports and combustion chamber by
scraping. Take care not to cause any
damage to the valve faces or valve
seat inserts. Scrape gently to avoid
scoring the cylinder head.
DO NOT, under any circumstance,
use caustic soda or potash for the
removal of carbon from aluminium
alloy.
Remove the piston rings carefully.
For cleaning the groove in the piston,
a piece of broken piston ring thrust
into a wooden handle and filed to a
chisel point can be used:
5. Decarbonising the Cylinder head - Combustion Chamber
CYLINDER HEAD
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8. Valves, Valve Guides and springs
VALVE & SPRING ASSEMBLY
Wear on the valve stems can be seen on examination
and if a definite step has formed, the valves should be
renewed. Before replacing the valves, they must be
ground on to their seats, if good faces are not formed with
a reasonable amount of grinding, the seats must be cut
with a cutter (included angle 90°) and the valve refaced in
a universal grinder. Do not attempt to form good seats by
an excessive amount of grinding. This will cause
pocketing and restrict the flow of gases. If a pocket has
already been formed this must be removed by cutting with
a valve seat cutter larger in diameter than the valve head.
Test the valve guides for wear by trying the fit of a new
valve in them. Both valves should be quite free, but the
exhaust valve has more clearance (.002") than inlet valve.
To remove the valve guides from the head, two special
tools are required which can be easily made. The first is a
piece of tube with an internal bore of not less than 7/8".
The second is a mandrel about 4" long made from 9/16"
diameter bar with the end turned down to 1/3" diameter
for a length of 1/2". Support the cylinder head on the tube
which fits over the collar of the valve guide. Using the
mandrel, force the guide out of the head with a hand press
or by using a hammer.
To fit a new guide, support the head at the correct angle
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
originally 2.020" and 2.095" for the inner and outer
springs respectively. If these have reached the specified
service limits, they should be renewed.
9. Decompressor
If the decompressor holds compression and operates
freely, there is no need to interfere with it except to
remove the carbon from the head of the valve. If the valve
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.
Compress the spring and remove the spring cap. Unscrew
the adjusting screw and locknut from the cable block and
pull the cable sideways out of the block. Push the spring
DECOMPRESSOR ASSEMBLY
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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
coating of grinding paste on the seat of the valve and twisting it to and fro by means of the cable
block at its upper end and occasionally lifting the valve from its seat. Do not rotate the valve through
a complete revolution before lifting, as this will groove the seat. After grinding, wash the whole
assembly thoroughly in petrol, opening and shutting the valve while doing so. Make sure that all
traces of grinding paste have been removed. If the paste should get into the cylinder serious damage
would be caused.
If the valve shows a tendency to stick-up in the body but otherwise 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 is badly 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.
Smear clean oil over the piston and space the ring gaps. The second ring is a taper ring and is
marked TOP on the upper surface.
WARNING: This mark should be on top when fitted. Reversing the ring will 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
insert the gudgeon pin. Secure the gudgeon pin with the circlips. Oil the cylinder bore and gently
push barrel over the piston while keeping the rings compressed in their grooves and seat it gently on
the barrel gasket. Refit the 1/4" nut above the timing chest.
When fitting the head again, apply jointing compound sparingly on both sides of the gasket.
Replace the six nuts and tighten them progressively and diagonally from one side to the other to
prevent distortion.
WARNING: Excess compound may block oilways.
Place the push rods with the adjustable parts downwards. The shorter pushrod is the inlet. Ensure
valve stem caps are fixed on the valve stems. Position the rockers and bearings, 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 again for tightness, after the engine
has been run long enough to get it thoroughly warm. Tighten the clamp nuts on crankcase finally. For
torque tightening of cylinder head nuts please refer torque chart on Page No. 100
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OIL FILTER ELEMENT IN TIMING COVER
SERVICE OPERATION - WITH ENGINE IN FRAME
1. Removal of the Timing cover
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 sealing washers, one for each screw.
NOTE: When removing or refitting the timing cover it is important that the engine is gently
cranked. This will prevent damage of the pump worm or the pump spindle.
Draw off the timing cover, tapping it lightly if necessary with a wooden mallet.
While refitting the timing cover ensure that the joint washer is correctly located over the oil holes,
using a little grease (not compound) to hold it in position.
Ensure that the cork plug is in position in the hole in the pump worm. If the plug is damaged it
should be renewed to ensure oil flow to the big end bearing.
NOTE: The filter chamber should be filled with clean oil before the timing cover is refitted.
Ensure proper functioning of oil pump by checking oil flow at rocker pipe union when the engine is
running at slow speed. Slacken the oil pipe banjo union to see the oil flow and clamp it again properly.
Wipe the oil that has oozed out.
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2. Cleaning/Replacement of Oil Filter
Element - Oil Feed and Return Filters
The oil filter is located in the timing cover
immediately below the oil pumps. The felt element
should be taken out and washed in petrol after the
first 800 Kms. and subsequently, every 4,000 Kms.
Fit a new element every 8,000 Kms.
The filter element can be removed by unscrewing
the nut holding the end cap in position. When re-
assembling the filter take care that no grit or other
foreign matter is sticking to it. After replacing the
filter element it is essential to run the engine at idling
for about five minutes to ensure that oil reaches the
big end. If the timing cover has been removed, fill the
filter chamber with clean oil before replacing the
cover.
The feed and return filters are fixed on the drain
plugs in oil sump and crank case. These can be
cleaned by rinsing in a solvent and during reassembly
ensure the filters are not twisted.
3. Overhauling of Oil feed and return Pumps
-Remove the timing cover.
-Remove the end covers from both pumps.
-Remove the pump discs and plungers.
-Remove the pump spindle which can be pulled out only from the front or return pump end.
-Check the fit of the plungers in the pump discs which should be sliding fit and should be able to be
moved in and out by hand.
OIL FEED & RETURN PUMP ASSY
Arrangement of oil filter
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When matching a plunger in the pump disc, if it is found to be too tight a fit, carefully lap the
plunger in the pump disc. Using metal polish until it is just free.
If the pump disc is not seating properly in the timing cover or if a new pump disc is fitted, it should
be ensured that the pump disc matches properly and has a perfect seating in the timing cover.
Lap the discs in the timing cover with fine metal lapping paste or liquid metal polish using special
tools 2034 for feed pump disc and 2035 for return pump disc, until a fine, grey surface is obtained on
the pump disc face.
NOTE: Replacement pump discs have a lip left at the opposite side of the lapped face. The
purpose of this is to hold the disc, central in the housing during lapping-in. It should be filed off
before the pump is finally assembled. Care should be taken not to damage the lapped face.
Wash all components and passages, thoroughly with petrol, after lapping, to remove all traces of
grinding paste. Check the pump disc springs for fatigue by assembling in the timing cover and placing
the pump covers in position. The latter should be held 1/8" off the timing cover if the springs are
correct. The pump spindle should be renewed if excessive wear has taken place on the teeth.
Reassemble the oil pumps, replacing the cover gaskets. Before fitting each cover fill the pump
chamber with clean oil. Having assembled the pumps, lay the timing cover flat and fill the oil ports
using an oil can. Turn the pump spindle with a screwdriver in a clockwise direction and it can then be
checked whether the pumps are operating correctly. Before replacing the timing cover on the engine,
fill the filter chamber with clean oil and fit the filter element.
NOTE: With the engine running, the oil feed to the big end can be checked by partially
unscrewing the feed plug in the timing cover between the oil pumps and the oil return can be checked
by slackening the rocker pipe banjo bolt on the cylinder head and observing the oil flow.
4. Removal of Pump Worm and Timing Pinion
Unscrew the pump worm using the hexagon head behind the worm, with special tool 2006.
Withdraw the timing pinion using special tool 2013.
CAUTION: The worm nut has a left hand thread. When turned clock wise the worm nut can be
loosened and when turned anti-clockwise the worm nut gets tightened.
NOTE: When refitting the timing cover ensure that the cork is in position in the worm nut and is
undamaged. This forms a seal between the oil feed plug and the oil passage in the crank shaft, timing
side. If necessary this should be replaced and care should be taken to have it fitted correctly.
CAUTION: If this cork is not fitted or damaged, the oil feed to the big end bearing through the
timing shaft will tend to escape past this point causing starvation of lubrication to the big end bearing
leading to premature failure of the big end floating bush, engine bearings and other parts.
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