Royal Enfield CRUSADER 250 User manual

RoyalEnfield
CRUSADER
TECHNICAL
DATA
250
CLIPPER
CRU
SAD
ER
250
SPORTS
FOR 1960 MODELS
Engine
type
...
Four-stroke
Fou
r-stroke
Four-stroke
Number
of
cylinders 1 o.h.v. 1 o.h.v., 1 o.h.v.
Cylinder head
Cast
iron
light
alloy*
light
alloy
Cubic capacity (c.c.) 248 248 248
Bore and
stroke
(mm.)
70x64·5
70 x64·5 70 x64·5
Compression
ratio
7·5
to
1 8
to
1 8·5
to
1
B.H.P. x R.P.M. 13
at
5,750
13!;-
at
5,750 17
at
6,250
Carbu
rettor
...
Amal Monobloc Amal Monobloc Amal Monobloc
Lighti
ng
and chargi
ng
set
Lucas A.C. Rectifier Lucas A.C. Rectifier Lucas A.C. Rectifier
Ignition D.C. Coil D.C. Coil D.C. Coil
Primary
è~ive
chain ... i" pitch i" pitch i" pitch
Final
drive
chain
!;-"
pitch
!;-
" pitch kH
pitch
-Pivoted fork Pivoted
fork
Pivoted
fork
Rear suspension hydraulic damping hydraulic damping hydraulic damping
Telescopic Telescopic Telescopic
Front
fork
automatic
lubrication
automatic
lubrication
automatic
lubrication
Hubs:
Front
light
alloy full width
light
alloy full width
light
alloy full
width
Rear Standard
Q.D. Q.D.
Gear
ratios (solo) 6·14. 8·29,
11
·
0.5,
18·0 6·14, 8·29, 11·05, 18·0 6·14, 8·29, 11·05, 18·0
Tyre
sizes:
Front, Dunlop ribbed (ins.) 3.25 X17 3·25 x17 3·25 x17
Rear, Dunlop
studded
(ins.) 3·25 x17 3·25 x17 3·25 x17
M.P.H.
per
1,000 r.p.m. in
top
gear 11·3
11
·3
11
·3
Approx.
maximum speed (m.p.h.)
...
70 70 75-80
Approx.
petrol
consumption
(m.p.g.) 100 100 95
Petrol
tank
capacity (gallons) 3 3
);!
4
Oil
tank
capacity (pints) 3 3 3
Brake
diameter
and
width:
Front
(ins.) 6 x 1 6 x 1 7 x
1!;-
Rear (ins.) ... 6 x 1 6 x 1 6 x 1
Seat height
approx.
(ins.) 29 29 29
Wheelbase
(ins.)
52
52 52
Overall
width
(ins.) ...
25!
25!;-
26
Ground
clearance (ins.)
5
1.
51. 51.
2 2 2
Weight
(lbs.) 300 305 305
Equipment Stop light Stop light
Air
cleaner
*Cast iron on
Crusade
r
"Airflow"

INSTRUCTION BOOK
for
the
1951-s8-s9-60 "CRUSADER 250"
1958-59-60 "250 CLIPPER"
~-
and
1959-60 "CRUSADER SPORTS"
MOTOR
CYCLES
THE
.
-
ENFIELD
CYCLE COMPANY
LIMITED
Head
Office
and Works :
REDDITCH, WORCESTERSHIRE
Telegrams: Telephone:
"Cycles, Phone, Redditch" Redditch 4222
(9
fines)

ILLUSTRATIONS
Fig. No. Description Page
Plan
of
Controls 5
2 Exploded View
of
Felt Oil Cleaner
li
3 Valve Clearance Adjustment
20
4 Timing Chain Adjustment
22
5 Clutch Adjustments
30
6 Exploded View
of
Q.
D.
Re
ar
Hub
31
7 Reassembly
of
Cush Drive
33
8
Rear
Wheel Adjustment
34
9 Section
of
Front
Fork
35
10 Steering Head Adjustment
37
11
Removal
of
Rear Mudguard
Unit
39
2

..
CONI'ENI'S
Page Page
Foreword 4 Reassembly of Engine after
Decarbonising
19
OPERATION OF THE
Valve Clearances
19
MOTOR CYCLE
Engine Bearings
20
Con trois 4 Removal and Dismantling
of
Starting the Engine 6 Engine
21
...
Timing Chain Adjustment 21
'
To Start the Machine 7
Driving Hints 7 Valve Timing
21
Running-in 8 Ignition Timing
23
...
· Sparking Plugs
24
Lighting Set
25
LUBRICATION
Carburettor 27
Lubrication of the Engine 9 Air Cleaner
28
Lubrication Routine for the
Engine 9 TRANSMISSION
Felt Oil Filter
11
Multi-grade Oils 11
Enfield Four-Speed Gear
29
Detergent Oils
12
Clutch 29
Lubrication of the Gearbox ... 13
Adjustment of Clutch Contrai 29
Lubrication of Chains • 13
Quickly Detachable Rear Hub
32
Grease Gun Lubrication 13
Adjustment of Chains
32
Lubrication of the Front Fork 14
FRONT FORK
TROUBLE ON THE ROAD Construction ...
33
Engine Stops owing tci Jack of
.Steering Head
36
Petrol
14
Engine Misfires or
Stops
REAR SUSPENSION 36
owing to Faulty Ignition ... 14
Other Causes of Engine Stop- ·
page
15 . MISCELLANEOUS
Clutch Trouble
16
Removal of Front Wheel 37
OVERHAULING THE
Removal of Rear Wheel 38
ENGINE
Removal of Re ar Mudguard
Unit...
39
Decarbonising 17
Fitting a New Rear Chain 40
Removal of Cylinder Head 17
Removal of Tyres
40
Remo val
of
Cylinder and Expanding
Hub Brakes
41
Pistop ... 17
Wheel Bearings
41
Removal of Valves 18
Cleaning
41
· ~
Reinoval of Carbon ... 18
"Dont's" for Drivers
42
Grinding-in Valves
...
i8 Guarantee
43
3
. .. .
.. •,- .
..

"Crusader 250," "250 Clipper"
and " Crusader Sports "
1 Foreword. These 248 c.c. O.H.V. models incorporate the
latest advances in modern motor cycle practice. The
short-stroke,
70 mm. boreX 64 ·5 mm. stroke engine is
of unit construction, the four-speed foot-operated gear-
box and oil tank being integral with the crankcase.
It
has dry sump lubrication, completely enclosed, and
lubricated valve gear and a very rigid one-piece, high
strength cast iron crankshaft. The complete engine and
gearbox, except for the crankshaft and connecting rod,
can be dismantled without removal from the frame.
An A.C. generator enclosed within the off-side crankcase
cover supplies current for lights and ignition coil. The
ignition switch, coil and battery are grouped together in
one box which also has compartments for
an air filter
and tools. Pivoted fork rear suspension and telescopic
front forks provide a high degree
of comfort and road
holding. The headlamp, speedometer, ammeter and
lighting switch are built into the "Casquette" which
shrouds the top
of the front forks.
Other items are full-width aluminium-alloy quickly
detachable rear hub on the two "Crusader" machines,
incorporating the Royal Enfield cush drive, full-width
aluminium-alloy front hub, 3·25" X
17" tyres and fully
enclosed rear chain.
Legshields and pannier equipment, specially de-
signed to fit this machine, are available as extras.
OPERATION OF TIIE MOTOR CYCLE
2 Controls. A rider should familiarise himself with
the positions and method of operation of the various
controls so that their use becomes automatic. The
controls are shown diagrammatically on page
5, and
in most cases the method of operation
is obvious. The
following notes may, however, be of assistance: -
4

"CRUSADER
25
0
,"
"250
CLIPPER"
AND
"CRUSADER
SPORTS"
CLUTCH
DIPPER
REAR BRAKE
IGNmo'
SW
I
TGe'
)
ON
TOOL
BOX
y
0
"
KICK STARTER
Fig.
1.-Plan
of
Controls.
BRAKE
Gear Control.
Move up for change to a lower gear.
Move down for change to a higher gear. A small pointer
on the outside
of
the crankcase cover indicates which
gear
is
engaged, neutral
is
between first and second gears.
Kickstarter.
Operate with a long swinging kick.
Lighting Switch.
Position " L " gives headlamp
pilot bulb. tail lamp and speedometer light. Position
"H"
gives headlamp main bulb, tail lamp and
speedometer light. A dipper switch on the handlebar
5

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
determines whether the main bulb
gives
a horizontal or
a dipped beam.
Ignition Switch.
Situated in the nearside toolbox
cover. Ignition
is
off
with the key in a vertical position.
Turn key clockwise for normal ignition, anti-clockwise
for emergency ignition. The emergency position
is
used
when the battery has become discharged; when the
engine has started, move the switch to the normal
position.
Petrol Filler.
To
open, turn to left till catch
is
felt,
push down and turn again to left
as
far as possible, then
lift
off.
To close, push down and turn to right as far
as possible.
Oil Filler.
On engine crankcase. Operates the
same way as petrol tiller.
Petrol Tap.
To
open, push hexagon end.
To
close,
push round end. A small lever above the petrol tap,
when turned clockwise, retains a reserve supply of fuel.
If
the reserve fuel
is
needed, turn the lever anti-clockwise.
The following contrai
is
not
shown in the
diagram:-
Carburettor Tickler.
On top of float chamber.
Depress to increase fuel supply before starting from cold.
3 Starting the Engine.
Fill the tank with petrol and
the oil tank in the engine crankcase with oil. Always use
one of the oils recommended in Section
8.
Turn on the
petrol. Depress the tickler of the carburettor once or
twice
until petrol can be felt in the float chamber,
but
do not flood the carburettor.
Place the gear control in
the neutral position, close the air lever, open the throttle
control about one-eighth, and smartly depress the kick
starter.
If
the engine fails to tire first or second time,
repeat with a slightly different throttle opening. The best
position for starting will soon be found from experience.
When starting a warm engine, do not flood the
carburettor or the mixture will become too rich.
Should any difficulty be found in kicking the engine
over, put the machine in gear and gently wheel the
machine backwards a
few
inches until compression can
6

"CRUSADER 250," "250 CLIPPER" AND "CRUSADER SPORTS"
be felt. Put the gear in neutral then administer a good
swinging kick to the starter pedal.
4 To Start the Machine. Pull up the clutch lever.
Engage the lowest gear by pressing the foot control up
as far as possible and then releasing it. Slowly release
the clutch lever, at the same time accelerating the engine
by opening the throttle slightly and the machine will
move away without jar or jerk. When the machine bas
attained sufficient speed (about
10 m.p.h.) de-clutch, at
the same time closing the throttle and changing to second
gear by pressing the foot control downwards as far as it
will go and then releasing it. Let in the clutch gradually
and open the throttle again until the speed of the machine
is sufficient to require a change into third gear (about
20 m.p.h.), when the foregoing operations are repeated.
Finally, change up to top gear when sufficient speed has
been attained in third (about
30 m.p.h.).
Note. The above speeds are intended only as a
rough guide for making a normal get-away on a level
road. When starting up a steep hill rather higher speeds
should be used in the intermediate gears.
Once top gear
is engaged and the machine is nmning
at a comfortable speed, the air lever should be fully
opened.
5 Driving Hints. For normal running on the level the
air lever can be left fully open, the speed being controlled
by the throttle, but when accelerating or climbing a hill
it may be necessary, especially while the engine
is cold.
partly to close the air lever
in order to prevent "pinking"
or knocking.
Never allow the engine to labour on a hill.
If the
machine will not climb comfortably
in top gear, change
down by de-clutching and moving the gear lever upwards
as far as possible and then releasing it, leaving the
throttle control open during the change. When in the
lower gear, the air lever may be opened
to suit the higher
engine speed.
If a hill is long and steep enough to
demand a change
to a lower gear, it is always desirable
to make this change before the engine has commenced
7

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
to labour. One change low down may save two higher
up and at the same time enable a faster climb to
be
made.
To
stop the machine, close the throttle and apply
the brakes; lift the clutch as the machine cornes to rest.
The engine may be kept running with the clutch out,
if
the stop
is
of only short duration, but neutral should be
found
if
the engine
is
kept running for any length of
time.
To
stop the engine, switch
off
the ignition. Engines
are sent out from the Works with the carburettors set at
a tick-over rate.
lt
is, of course, possible to set the
throttle stop to close the throttle completely, in which
case the engine
will
stop whenever the throttle
is
closed.
Note that the positions of the handlebars, footrests
and all controls (including the gear lever and the brake
pedal) are adjustable. A rider cannot have proper
control of
his
motor cycle unless he
is
comfortable and
the controls are conveniently situated. Riders should
set the controls to suit their individual requirements.
6 Running-in.
Ali Royal Enfield motor cycles have a
special oval formed piston which minimises the risk of
seizure with a
new
engine. Nevertheless, careful running-
in
is
highly desirable
if
the best results are to be obtained.
lt
is
recommended, therefore, that a
new
machine
should not
be
driven at a speed exceeding
30
m.p.h. for
the first
200
miles, and, until at least
500
miles have
been covered, the throttle should not be opened above
half way, except for very short periods. After this
distance short bursts of speed are desirable in order to
hasten the bedding down of the thrust faces of the piston.
Gradually increase the duration of these speed bursts
until the machine will stand large throttle openings for
indefinite periods. Note the importance of progressively
increasing the work done by the engine. Running 1,000
miles at
30
m.p.h. will
not
bed down the piston to
enable it to withstand continuous high speed running.
Piston temperature
is
the important factor and this
depends not only on speed and throttle opening, but
also on how long that particular throttle opening bas
been sustained. Thus a machine after the preliminary
8

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
200 miles might stand full throttle for half a mile
and
yet pull
up
if
driven
at
three-quarter throttle for five
miles
or
so.
If
the engine
is
run tao long on a large throttle
opening
and
shows the slightest tendency
to
pull
up
or
seize, lift the clutch
and
close the throttle. Even
if
a
seizure then occurs it will
do
little or
no
damage
and
after cooling for a minute
or
two the piston will free
itself.
If
a seizure does occur, the piston should be
examined by a competent mechanic
to
have any high
spots eased down.
LUBRICATION
7 Lubrication of the Engine.
The
lubrication is on
the dry
sump
system, incorporating a duplex pump, a
large, felt filter and
an
oil reservoir cast integrally with
the crankcase.
The
delivery
pump
supplies oil
ta
the big-end
and
piston, having first passed it through the felt filter.
From
the sump, the return
pump
picks
up
the oil
and returns it
ta
the reservoir,
but
a by-pass. controlled
by a ball valve, leads some of this oil through an external
pipe
to
the rocker gear.
From
here, oil finds its way
down the
pUsh
rad
tubes to the camshaft housing
from whence it passes into the primary chaincase and
then
back
into the sump.
8
LUBRICATION
ROUTINE
FOR
'l'HE
ENGINE
Never allow the oil
tank
to become empty. Since there
is
no
reserve of oil in the sump,
an
empty tank means
immediate shortage of oil to the working parts.
The
oil
Ievel should be kept well above the
bottom
of the
dip-
stick
attached
to
the filler cap. By keeping a large
quantity of oil in circulation, its temperature
is
kept low,
and the oil retains its lubricating qualities for long
periods.
Do
not, however, fill the tank above the oil
retum
plug,
or
oil may escape past the tiller cap.
If
difficulty
is
experienced in obtaining the grades recom-
mended for hot climates
or
summer
use,
the
alternatives
for winter use
or
cold climates
can
be used. These fiow
freely when cold and
at
the same time have adequate
9

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
RECOMMENDED LUBRICANTS
1
Esso Extra B.P. Shell
X-100
Castro! Mobiloil Motor Oil Energol
Motorüil
Engine
(summer) XXL
BB
40/50 S.A.E.40
40
Engine
(winter) Castrolite A 20W/30 S.A.E.30
30
Gearbox
XXL
BB
40/50 S.A.E.40
40
Chains-
front Castrolite Arctic 20W/30 S.A.E.20 20
rear
XXL
BB
40/50 S.A.E.40
40
Grease
Gun
Castrolease Mobilgrease Esso Grease Energrease Retinax A
(Heavy) (No.
4)
C.3
FrontForks
Castrolite Arctic 20W/30 S.A.E.20
20
heat-resisting properties.
The
importance of efficient
lubrication cannot be over-estimated.
The
use of cheap
oils
is
false economy and
we
strongly recommend the
oils mentioned above,
as
we
have found from experience
that these are the most suitable for our engines. It
is
advisable to specify the brand
as
well as the grade and.
as an additional precaution, oil should be bought from
branded cabinets or sealed cans.
During the nmning-in period
we
recommend the
addition of Acheson's Colloïdal Graphite
to
the oil in
the engine.
After the first
500
miles and subsequently about
every 2,000 miles, the oil should
be
drained from the
tank and engine sump and the
felt
oil filter cleaned (see
Section
9).
To
drain the tank remove the hexagon-
headed plug underneath the nearside of the engine.
The
small screw on the same side of the engine drains the
sump.
The
tank should be swilled through with clean
oil. This procedure
is
conveniently carried out when the
engine is being decarbonised. The oil will
fiow
more
readily
if
the plugs are removed at the conclusion of a
ride, alternatively, the tank and sump may be allowed to
drain overnight. Waste of oil
is
reduced by allowing
~e
oil level in the tank to become reasonably low before
draining.
10

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
GEARBOX
---FILLER
PLUG
Fig.
2.-Exploded
View
of
Felt Oil Cleaner.
9 Felt Oil Filter. The construction
of
this is
cl~arly
shown
in
Fig.
2.
The
felt
filter element should be
cleaned by washing in petrol every 2,000 miles and in
addition the element should
be
renewed every 5,000
miles.
10
Moiti-grade Oils. Sorne
of
the manufacturers
of
the
lubricants inthe table above offer special engine lubricants,
the viscosity
of
which
is
Jess
sensitive
than
usual to tem-
perature changes. These are classed as S.A.E.
IOW
/30
or
IOW
/40 oils. Their use will facilitate starting
at
low
temperatures
but
may result in an increase in the rate
of
oil consumption. These oils are ail
of
a highly detergent
nature
and
the precautions given in paragraph
11
should be
followed
if
a change to them is made after a long period
of
use
on
a non-detergent oil.
Castrolite
and
Esso Extra Motor Oil are
of
a mild
multigrade character (S.A.E. 20W/30)
and
have only
11

"CRUSADER 250," "250 CLIPPER" AND "CRUSADER SPORTS"
mild detergent properties. They are therefore especially
recommended for winter use if difficulty is experienced
with starting owing to the gumminess of normal S.A.E.30
oils when cold and if the owner does not wish to take the
precautions necessary when changing to a highly deter-
gent oil.
11 Detergent Oils. Many of the oils which we recom-
mend contain detergent additives designed to counteract
ring sticking and sludge formation.
The degree of detergency varies not only between
one make and another but in some cases between different
grades of the same make and may even be different for
the same grade and make of oil in different parts of the
world.
If one of the more highly detergent oils is used in
an engine containing large deposits of sludge which have
accumulated when running on another grade of oil this
sludge will be loosened and may cause seizure and other
trouble due to blockage of filters and oilways.
For this reason the following procedure should be
carried out when changing to one of the more highly
detergent oils, particularly if the engine bas been used
on a normal grade of oil or bas not had the oil drained
and changed at regular intervals as recommended in
Section 8.
(1) Drain the engine when the oil is hot and refill
with detergent oil.
(2) Run the machine at moderate speed for not
more than 50 miles.
(3) Drain the engine again when the oil is hot, flush
out the oil tank with detergent oil, remove, clean
and replace filters (preferably fit new felt filter
element). Refill with detergent oil.
(4) When machine has run a further 100 miles,
check condition of filters. If clogged, repeat
operation (3).
Note. Although the detergent additive in the oil
keeps the engine clean and prevents sludge formation, it
naturally becomes used up in the process. If an engine
12

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
has a very low oil consumption so that
"topping
up"
is
seldom
(if
ever) necessary, the additive may all become
used up, in which case sludge formation will occur at
the normal rate.
It
is
therefore just
as
important to drain
the engine at regular intervals with a detergent oil as
with one having no detergent additive.
Your dealer will advise you which makes and grades
of
oil in your country have sufficient detergency to
necessitate the above enurr.erated precautions being
taken.
12
Lubrication
of
the
Gearbox.
The gearbox should
be
kept filled to the correct level with engine oil. On no
account should heavy yellow grease
be
used in the
gearbox. The tiller plug
is
situated on the top
of
the
crankcase. The screw in the middle
of
the off-side
crankcase cover should
be
removed and the gearbox
fi
lied until oil runs from the screw hole. Wait until the
oil stops running before replacing the screw. The
gearbox may
be
drained when desired by removing the
hexagon-headed drain plug situated underneath the
offside
of
the crankcase.
13
Lubrication
of
Chains.
The front chain and timing
chain are automatically lubricated, the correct quantity
of
oil being maintained in the chaincase by the oiling
system of the engine.
If
the front chaincase has been removed for any
reason, it should be replenished with about one-third of a
pint of engine oil before running the engine, otherwise
the chains will not be lubricated until the oiling system
has
fi.lied
the case to the correct level.
The maintenance
of
the rear chain on the "Crusader
250"
is
very much simplified by its enclosure in a pressed
steel case. Lubricate at frequent intervals with engine
oil.
14
Grease
Gun
Lubrication.
The rear brake pedal,
gear control and speedometer drive should
be
greased
with a grease gun every 200 miles or once a week.
The rear suspension pivot spindle which has greasers
at either end should be lubricated every
500
miles.
13

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
Use one of the following greases in the gun: -
Castrolease (Heavy), Shell Retinax A,
*Esso Grease, Energrease C.3
or
Mobilgrease (No. 4).
15 Lubrication of the Front Fork. The oil level in
the telescopic front fork
is
determined by a small screw
at the back of each sliding fork
leg.
Before topping
up
the forks, first place the machine on the centre stand,
thus allowing the forks to extend.
To
fill
each fork leg
to the correct level, remove the plug screws from the
fork head and the oil screws
at
the back of the sliding
fork leg. Pour oil in
at
the top until it runs out from
the level holes. Wait till oil has stopped running and
replace level plugs and plug screws.
Recommended grades of oil are: -
Castrolite : Mobiloil Arctic :
Esso 20W/30 : Shell X-100
20
:
Energol SAE.20.
TROUBLE
ON
THE
ROAD
16 Royal Enfield Motor Cycles enjoy a wonderful
reputation for reliability. Trouble on the road is very
unusual; nevertheless stoppages may sometimes occur
and
it
is hoped
that
the following hints may help towards
the speedy location
of
the trouble. ·
17
Engine Stops owing to Jack
of
Petrol. This is the
commonest form
of
engine stoppage. The first symptoms
are irregular firing, which is temporarily cured by closing
the air lever. Make sure
that
there is plenty
of
petrol
in
the tank.
If
so, disconnect
the
petrol pipe
at
the car-
burettor end and turn
on
the tap.
If
a good fiow
of
petrol
occurs, the stoppage is probably
in
the jet itself.
If
the
fiow from the petrol pipe is restricted, the stoppage lies
either in the petrol tap
or
in
the pipe itself.
18
Engine Misfires or Stops owing to faulty Ignition.
The symptoms in this case are that the engine will not
*
Known
as Esso
Cup
Grease
in
overseas countries.
14

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
run regularly and
is
very hard to start.
In
other cases
the engine may suddenly " eut out " without any warn-
ing. First see that the high tension lead has not become
disconnected
at
either end and
is
not worn
or
burnt
through, allowing the bare wire to touch some metal
part of the machine. See also that the plug insulator
and high tension lead are not wet.
If
ail the above
is
in order, remove the sparking plug
and hold it with the body touching the engine cylinder,
but with the terminal clear of the machine and connected
to the high tension lead.
Turn
the engine round by the
kick starter.
If
a good spark is obtained at the plug
points, the ignition
is
in order and the trouble lies else-
where.
If
no spark,
or
a very weak spark,
is
obtained,
remove the plug and hold the end of the high tension
wire about
l"
from a metal part of the machine and
rotate the engine.
If
a spark
is
obtained frorn the wire,
the fault lies with the sparking plug.
If
this
is
oily
or
sooty it can be taken apart and cleaned,
but
if
the points
are red and burnt the plug has been too hot and a new
one should be fitted.
The
gap between the plug points
should be ·018" to ·025".
If
the plug is satisfactory, the trouble lies elsewhere.
See
that
the contact breaker points are clean and
that
they open and close properly. These should open to
·014"
to
·016".
A sticking rocker arm may be another cause of
failure, while faulty low tension leads, battery and other
connections may a
il
result
in
.
stoppage
or
poor running.
Ignition trouble can corne, of course, from a faulty
condenser or coi!.
Failure of the generator to charge the battery may
be due to a faulty rectifier
or
short circuits and a low
charge rate can be caused by the connections joining the
generator coils making contact with the inside of the
crankcase cover.
19
Other
Causes of Engine Stoppage. Other possible
causes of an engine stoppage are: -
15

"CRUSADER 250," "250 CLIPPER" AND "CRUSADER SPORTS"
( l) Water in Carburettor. The symptoms are usually
intermittent misfiring and banging in the silencer
following a heavy rainstorm.
The remedy
is to clean out th~ ftoat chamber and
jets.
(2) No clearance at tappets. This is apparent by an
entire lack of compression when turning over with
the kick starter. The remedy
is to adjust the tappets.
(3) Sticking Valve. In this case there is no compression
and excessive tappet clearance, the valve remaining
partly open. The valve may free itself on cooling,
but sometimes it
is necessary to dismantle the engine
to free the valve.
(4) Broken Valve. This trouble is very rare and is
usually caused by consistent overdriving of the
machine and by neglect of the tappet clearance
(see
Section 28). The symptoms are that the engine
" cuts out " suddenly and stops with no tappet clear-
ance. Furthermore,
it is not possible to obtain any
clearance at the tappets. A valve breakage on an
O.H.V. engine
is likely to have very serious
consequences.
(5) Seized Piston. This is caused by overdriving a new
machine before the engine is properly " run in." The
symptoms are loss of power and a tendency to
"pink" followed by the engine locking up solid. An
·aluminium piston will always free itself if allowed to
cool.
If the clutch was withdrawn and the throttle
closed before the final seizure the consequences may
not be serious, but the cylinder and piston should
be
examined as soon as possible by a competent
mechanic to have any score marks removed. A
seizure may also occur through running with
insufficient oil, in which case the consequences
will
be far more serious.
20 Clutch Trouble. A slipping clutch may be caused
by
Jack of clearance in the control (see Section 39).
A binding clutch is caused by too much slack in
the control wire. New clutches sometimes tend to bind
until the inserts have bedded down dead level.
16

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
OVERHAULING
THE
ENGINE
21
Decarbonising. When
an
engine has been in use
for some time, carbon deposit forms
on
the piston and
cylinder head and the engine must be partly dismantled
to allow this deposit to be scraped off and the valves to
be re-ground.
The
time when decarbonising becomes necessary
will
be
indicated by
an
increased tendency to " pink "
and
will occur after approximately the first 2,000 to 2,500
miles, and' subsequently at intervals of about 5,000 miles.
22 Removal of Cylinder Head.
Turn
off the petrol
tap
and disconnect the petrol pipe from the tank. After
removing the boit attaching the front of the tank to the
frame, the rear of the tank
can
be pulled upwards,
releasing the clip holding it to the
top
tube of the frame,
and the tank lifted clear. Unscrew the central nut
securing the rocker box cover, remove the cover
and-
carefully·
-the
gasket. Detach the oil pipe assembly
which leads from the crankcase to the cylinder head.
Remove the exhaust pipe, sparking plug and the cylinder
head steady. Roll back the rubber connection from the
carburettor air intake to the air cleaner and remove the
carburettor from the cylinder head. Undo the
five
cylinder head holding down nuts (four inside the rocker
box and one near the sparking plug hole).
Machines having an alloy
head
have an extrasecuring
pin in the push rod tunnel.
In
addition to removing the
five holding down nuts, also
undo
this pin, which has a
hexagon socket head.
Lift the cylinder head about one inch and remove
the push rods; the head can now
be
lifted clear.
23
Removal of Cylinder and Piston. Whilst it
is
not
strictly necessary to remove the cylinder barrel and piston,
this should preferably be done so
that
the condition of
the piston, rings and big-end bearings can
be
examined.
To
remove the cylinder barrel after removal of the head,
simply lift the barrel off the five long studs.
To
remove
the piston, remove one of the circlips holding the
17

"CRUSADER
250," "250
CLIPPER"
AND
"CRUSADER
SPORTS"
gudgeon pin in place, push out the pin and lift the piston
from the connecting rod. Note that the piston has a
split skirt and that the split should face forwards. The
piston
is
marked with the word " Front "
by
the leading
valve depression in the piston crown.
24
Removal of Valves. Lift or prise off the hardened
caps from the ends of the valve stems, then, compress
the valve springs with a suitable compressor. Lift out
the split, conical collars and remove the compressor
when the springs and valves may be withdrawn. Keep
the end caps, split collars, springs and other parts paired
off
with their respective valves and replace them in the
same positions when reassembling.
On the "Crusader Sports" there
is
some slight
difference in valve spring anchorage. There are no end
caps on the valve stems and the alloy top spring collars
are retained by split conical cotters which have a narrow
interna! projection which
fits
into a corresponding
groove in the valve stem.
25
Removal of Carbon. Remove carbon from the
valves, ports and combustion chamber by scraping or
(only if the cylinder head
is
cast iron)
by
immersion in
a solution
of
4 ozs.
of
commercial potash to a gallon
of
water. Carefully remove the piston rings. Remove
carbon from the ring grooves and the top
of
the piston
by
carefully scraping, taking care not to dig into the
aluminium. On
no
account
allow
potash solution to
corne
into contact with the aluminium piston.
26
Grinding-in Valves. Sinear the valve seats with a
little grinding compound, replace the valve in position
and rotate
it
with a semi-rotary motion by using a tool
with a suction cap frequently lifting it off its seat and
gradually working the valve round so that each point on
the valve face cornes into contact with each part of the
seat. Continue grinding until a bright ring
is
obtained
on both the valve and its seating.
If
the valve or seats are very badly pitted and
will
not form good faces with a reasonable amount of
grinding, the parts should be returned to the Works for
18