Suzuki Spark Plug NGK - DL 650 V-Strom 2004-2012
Part No: CR8E (1275)
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This is the Standard plug for the DL650's V-Strom
Technical information
Operating Temperature
The operating temperature of a spark plug varies between 450-870 °C.
Heat Range Explanation
Typically the heat range for NGK Spark Plugs varies from 2-11.
This
number indicates the thermal characteristics of a spark plug,
or how
‘hot’ or ‘cold’ a spark plug is. The term hot/cold is commonly used to
describe whether a spark plug heats up easily (hot) or whether it
provides
resistance to heating up (cold).
Generally, low power engines such as lawn mowers don’t produce a large
amount of heat, hence use a low heat range (or hot) spark plug such as a
4 heat range. This means the spark plug will heat up easily and reach
its
optimal operating temperature. High performance engines on the other
hand produce a large amount of heat, hence a high heat range (or cold)
spark plug such as a 10 heat range needs to be used to resist the heat
developed by the engine.
Several factors influence the heat range of a spark plug, although
typically
the insulator nose design provides an indication of the heat
range of a
spark plug.
When a spark plug absorbs heat produced from combustion, the heat is
transferred through the centre electrode and insulator nose to the metal
shell, which then transfers the heat into the engine casing and
circulating
coolant.

A low heat range (or hot) spark plug typically has a long thin
insulator
nose which will heat up easily however will not dissipate
readily to the
metal shell (above left). Conversely, a high heat range
(or cold) spark
plug has a short thick insulator nose which will
dissipate heat much
easier (above right).
When the heat rating is too high:
The spark plug temperature remains too low and causes deposits to
build
up on the firing end; the deposits offer an electrical leakage path
that gives rise to loss of sparks.
When the heat rating is too low:
The spark plug temperature rises too high and induces abnormal
combustion (pre-ignition): this leads to melting of the spark plug
electrodes
as well as piston seizure and erosion.NGK Spark Plugs pioneered the use
of a copper cored electrode in 1958,
which enables a spark plug to heat up
quickly and also dissipate heat
quickly giving an ultra wide heat range. It is
essential to use a spark
plug that fits a specific engine and its conditions of use.
As spark plugs are positioned in the head of an engine, their analysis
can give
a good indication of how your engine is operating.

Spark Plug Analysis
Appearance of a used spark plug tells a lot about the operating
conditions
of the engine and the plug. Thus the analysis of a plug plays
an important
role in the maintenance of a car.

1 : Carbon Fouling
Carbon fouling is the most common spark plug related failure, but is not
a spark plug fault.
Carbon deposits are conductive, and as they
accumulate along the insulator nose they reduce
the insulation
resistance of the spark plug. As electricity always takes the path of
least resistance
a misfire may occur if a significant amount of carbon
deposits accumulate. A spark will not form
as electricity can track
along the conductive carbon deposits to the metal shell (as shown in red
below)
rather than forming a spark across the electrode gap which has a
very high resistance.

As mentioned the optimal operating temperature range for a spark plug
is 450 – 870°C, 450°C
is the spark plug self cleaning temperature at
which point carbon deposits will burn off. However,
if too cold a spark
plug is used and this temperature is not achieved carbon fouling will
occur.
This is the most common reason for carbon fouling.
Other causes for carbon fouling include:
Causes
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Corrective actions
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Air/fuel mixture (A/F) too rich
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==>
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It is necessary to service the carburetor, the auto choke system or the fuel injection system.
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Incorrect adjustment of carburetor
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Faulty auto choke system
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Faulty fuel injection system
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Faulty electrical system
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It is necessary to service the electric system.
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Poor connection of high tension cables
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Inadequate running conditions
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It is necessary to run at higher speeds (about 80 km/h) from time to time.
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Prolonged idling
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Continuous low speed driving
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Too cold a spark plug
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==>
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Use a hotter spark plug
(Example: BK R6E-11 --> BK R5E-11)
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Air cleaner contaminated
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As carbon builds up, the insulation resistance of the spark plug drops
and the voltage generated
by the ignition coil is reduced. When the
generated voltage becomes lower than the required
voltage of a spark
plug (the voltage needed to cause sparks at the spark gap), sparking is
suppressed and mis-firing occurs.
2 : Terminal Nut Wear

Excessive
vibration of the engine may lead to abnormal wear of the terminal nut.
As a result,
the cover may come off the plug. For vehicles whose engines
vibrate more than others,
such as watercraft and snowmobiles, solid
post terminal plugs with excellent vibration
resistance and wear
resistance are recommended.
3 : Flash-Over - Spark leakage from terminal to metal shell
Flash-Over When the spark gap
has widened due to wear of the electrodes,
a higher voltage is required.
The flash-over occurs when the required voltage
between the plug
electrodes is higher than the voltage flying between the
terminal and
metal shell.
The plug cable material hardens as time elapses, which in turn reduces
the
tightness of the cover and insulator, lowering the preventive power
for flash-over.
As a higher voltage is required for a turbo charged engine, flash-over
is more
likely to occur. It is important to recognise that a plug cable
is a consumable
part which needs to be replaced periodically. When there
is no spark after washing
the car or the engine room, check whether
water has entered the plug cover or not.

4 : Corona Stain
A removed spark plug sometimes has discolouration around the insulator
surface which
looks like gases have leaked between the insulator and the
shell.
It is not a stain caused by gas leakage but by corona discharge (Carona Stain).

Mechanism of corona discharge
The high voltage applied to the spark gap is also applied to the area
between the
centre electrode and the metal shell, causing an insulation
breakdown of the air
at the gap (a) between the insulator and the metal
shell. The phenomena is called
a corona discharge. The generated carona
discharge develops toward the terminal nut.
This last process is the
pale blue carona discharge that is observed at night.
5 : Metal shell - Rust, breakage at caulked portion
When water has entered the plug hole due to water resistance of the
plug cover or,
in the case of a motorcycle, when water has accumulated
due to the inadequate
draining through the plug hole, the metal shell
may rust.
The rusting of the metal shell causes no deterioration of the function
of the spark plug.
Note, however, that water inside the cover may
prevent sparks from being generated.
If the plug is forced to remove when the returning torque is abnormally
high due to some
causes such as plug thread seizure, the plug may break
at the caulked portion of the metal shell.
When returning torque is high, the engine should be first warmed up.
Then,
by spraying penetrating liquid around the plug thread and leaving
it for a while,
the plug can sometimes be removed more easily.


6 : Firing End - Broken ceramics, melted electrodes, deposits
When the firing end of the plug has overheated, the ceramics may break
or the electrodes may melt. Under usual engine condition, the plug does
not overheat. Note,
however, that it gets extremely hot in the case of
abnormal combustion
(ex. high - speed knocking, pre - ignition).
When the A - F setting is lean due to a faulty fuel system, the
combustion
temperature may rise, resulting in abnormal combustion. The
engines
cooling system may be faulty. When the spark timing is too
early, the
combustion temperature may rise, resulting in abnormal
combustion.
When deposits (generating from combustion) are accumulated
in the
combustion chamber, the combustion temperature may rise,
resulting
in abnormal combustion.
When deposits have accumulated on the firing end of the plug,
deposits
may overheat, causing abnormal combustion.
Especially in a two - cycle
engine, oil gets burned and remains in
the combustion chamber as
deposits, accumulating on the plug as
well. It is necessary to remove
these deposits periodically.
In engines that consume larger amounts of oil, oil may enter the
combustion chamber. It is necessary to check the amount of deposits
during inspection of the plug. Burning of oil can also be detected by
visible white exhaust gas emitted from the tail pipe.
7 : Dry and wet fouling
Wet fouling is fundamentally similar to carbon fouling. Although the
root
cause may vary due to a number of reasons, in essence the
insulation
resistance is reduced allowing a spark to track along the
insulator nose
and earth to the metal shell rather than forming a spark
across the electrode
gap as desired. Please see 1. Carbon Fouling
8 : Insulator - Breakage at the corrugation and caulked portion
When removing or installing the plug, the plug wrench may slip or be
tilted and may hit the
corrugation of the plug against the inside,
breaking the insulator.
Depending on the type of plug wrench, the plug may break at the caulked
portion of the
metal shell. This may not be noticeable from the outside
appearance.
Slipped wrench leaves a mark on the hexagonal portion of the metal
shell. A plug wrench
with a definite hexagonal shape should be used. A
rounded or loose wrench should be
either avoided or used with special
care.
9 : Under or over tightenin
When the plug has not been tightened enough, the combustion gas leaks
out
the thread portion. This reduces the radiation of the plug, causing
the metal
shell to be heated, resulting in discolouration of the metal
shell plating.
If the metal shell continues to overheat the plug
temperature may rise and
abnormal combustion may result. When the plug has been tightened too
much the thread neck portion of
the metal shell will be lengthened.
When the threaded neck portion is
lengthened, the insulator and metal will
not seal tight enough, causing
the combustion gas to leak. When the gas
continues to leak, the plug
will be overheated and abnormal combustion may result.
The plug should be tightened to the following recommended torques and turning angles.
When the plug is tightened too much the metal shell thread neck may be broken at
around the first to second thread. The plugs with smaller diameter portions,
the D (12 mm) or C (10 mm)
types thread neck portion is not very strong.
Observe the recommended
torque and turning angle and tighten with special care.
10 : Plug socket troubles
Damage to spark plugs during installation can easily occur and will
often result
in an intermittent misfire or no spark at all. Care must
be taken during
installation that the spark plug socket is not slanted
and does not slip causing
insulator breakage (See Figure 1). Internal
damage can still occur without the
insulator actually breaking. Any
horizontal force can either bend the terminal
post internally or result
in internal cracking of the insulator.
To avoid plug damage the following qualities are required in a wrench
1. That it fits the spark plug "hex" properly.
2. The inner space must be large enough to avoid contact with the insulator.
3. The spark plug socket must completely cover the "hex" portion of the metal shell.
4. A hexagonal socket is preferable as it is less likely to slip than a twelve point star type.

11 : Examples of problems caused by excessively over long periods of use
Deposits accumulated on the firing end may induce abnormal combustion
(pre-ignition)
causing problems that include melting of the electrodes.

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Good
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Worn Electrodes
If the edges of electrodes are worn and rounded, sparks will not
easily occur, which leads to engine starting problems and mis-firing
during running: maximum power cannot be obtained from the engine.
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Fouled
Power leaks through the carbon accumulated on the firing end, causing mis-firing as well as hindering engine starting.
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Deposits
The deposits accumulated on the spark plug overheat and cause
abnormal combustion (pre-ignition) that may lead to melting of the
electrodes of the spark plug.
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Why is the firing end appearance of a spark plug important?
Because the Firing end appearance reflects the suitability of the spark
plug as well
as the condition of the engine. There are three basic
criteria: good, fouled,
and overheated. The firing end appearance also
depends on the spark plug tip temperature.

The boarder-line between the fouling and optimum operating regions
(450
degrees Celsius) is called the spark plug self cleaning temperature.
It
is at this temperature that the deposits accumulated are burnt off.
What is spark plug fouling?
It is a phenomenon by which carbon attached to the firing end causes electrical
leakage that leads to mis-firing.
As the high voltage generated by the ignition coil leaks away through
the carbon,
mis-firing may occur and cause running and starting
difficulties.
What is spark plug overheating?
Prolonged overheating may induce abnormal combustion (pre-ignition), resulting
in melting of the spark plug electrodes.
Overheated spark plugs have a white insulator surface at the firing end
speckled
deposits. Electrode melting represents excessive overheating.
When the spark plug
temperature exceeds 870°C, the firing end serves as a
heat source before sparking
and induces abnormal combustion
(pre-ignition), possibly damaging the piston.

Causes of overheating and corrective actions
Causes
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Corrective actions
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Ignition timing too far advanced
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==>
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Adjustment of ignition timing is required.
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Air/fuel mixture(A/F) too lean
|
==>
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Adjustment of air fuel ratio (A/f) is required.
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Insufficient cooling water and lubricants
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Top up cooling water and lubricants
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Applied turbo boost pressure too high in the case of a turbo engine
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Adjustment of turbo boost pressure control is required.
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Insufficient tightening of spark plug
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==>
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Tighten to specified torque
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Use of too hot a spark plug
|
==>
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Use colder spark plug
(Example: BK R5E-11 --> BK R6E-11)
|
What is lead fouling?
Lead deposits accumulated on the spark plug firing end help electricity to leak
away and result in mis-firing. When the lead contained in gasoline as an octane
enhancer, adheres as
the firing end of the spark plug, the high voltage generated
by the
ignition leaks through the lead deposits and causes mis-firing during
acceleration. This problem often takes 2,000 ~ 3,000 km (1,200 ~ 1,800
miles)
to become apparent.

Insulation resistance of a spark plug vs. vehicle speed.
Lead fouling does not appear during starting or low speed running.
On
the other hand, mis-firing occurs when accelerating from the
middle
speed range since the insulation resistance of the spark
plug drops
quickly.

Better selection of spark plugs.
Use hotter type (Example: CR7E - CR8E)