Spark plugs for the Bros:
Standard:NGK DPR8EA-9
High performance:NGK DPR8EIX-9 (IRIDIUM IX)
For cold climate:NGK DPR7EA-9
For extended high speed riding:NGK DPR9EA-9
Spark plug gap:0.8 to 0.9 milimetres
As far as I know the only tool that can remove the spark plugs from the Bros
is the Genuine Honda Spark Plug Wrench, Part number: 89216-MJ1-000.
NORMAL
Combustion deposits are slight and not heavy enough to cause any
detrimental effect on engine performance.
Note the brown to greyish tan
color,
and minimal amount of electrode erosion
which clearly indicates the
plug is in the correct heat range
and has been operating in a "healthy"
engine.
MECHANICAL DAMAGE
May be caused by
a foreign object that has accidentally entered the combustion chamber.
When
this condition is discovered,
check the other cylinders to prevent a
recurrence,
since it is possible for a small object to "travel" from one
cylinder to another
where a large degree of valve overlap exists.
This
condition may also be due to improper reach spark plugs
that permit the
piston to touch or collide with the firing end.
OIL FOULED
Too much oil is entering the combustion chamber.
This is
often caused by piston rings or cylinder walls that are badly worn.
Oil may
also be pulled into the chamber because of excessive clearance in the valve stem
guides.
If the PCV valve is plugged or inoperative it can cause a build-up of
crankcase pressure
which can force oil and oil vapors past the rings and
valve guides into the combustion chamber.
OVER HEATED
A clean, white insulator firing tip
and/or excessive
electrode erosion indicates this spark plug condition.
This is often caused
by over advanced ignition, timing,
poor engine cooling system efficiency
(scale, stoppages, low level),
a very lean air/fuel mixture, or a leaking
intake manifold.
When these conditions prevail, even a plug of the correct
heat range will overheat
INSULATOR GLAZING
Glazing appears
as a yellowish, varnish-like color.
This condition indicates that spark
plug
temperatures have risen suddenly during a hard, fast acceleration
period.
As a result, normal combustion deposits do not have an opportunity to
"fluff-off" as they normally do.
Instead, they melt to form a conductive
coating and misfire will occur.
PRE-IGNITION
Usually one or a combination of several engine operating
conditions
are the prime causes of pre-ignition.
It may originate from
glowing combustion chamber deposits,
hot spots in the combustion chamber due
to poor control of engine heat,
cross-firing (electrical induction between
spark plug wires),
or the plug heat range is too high for the engine or its
operating conditions
GAP BRIDGING
Rarely occurs in automotive engines, however,
this condition
is caused by similar conditions that produce splash fouling.
Combustion
deposits thrown loose may lodge between the electrodes,
causing a dead short
and misfire.
Fluffy materials that accumulate on the side electrode
may
melt to bridge the gap when the engine is suddenly put under a heavy load.
SPLASH FOULED
Appears as "spotted" deposits on the firing tip of the
insulator
and often occurs after a long delayed tune-up.
By-products of
combustion may loosen suddenly
when normal combustion temperatures are
restored.
During hard acceleration these materials shed from the piston crown
or valve heads,
and are thrown against the hot insulator surface.
DETONATION
This form of abnormal combustion has fractured the insulator
core nose of the plug.
The explosion that occurs in this situation apples
extreme pressures on internal engine components.
Prime causes include
ignition time advanced too far,
lean air/fuel mixtures, and insufficient
octane rating of the gasoline
ASH FOULED
A build-up of combustion deposits stemming primarily from
the
burning of oil and/or fuel additives during normal combustion ... normally
non-conductive.
When heavier deposits are allowed to accumulate over a longer
mileage period,
they can "mask" the spark, resulting in a plug misfire
condition.
CARBON FOULED
Soft, black, sooty deposits easily identify this plug
condition.
This is most often caused by an over-rich, air/fuel
mixture.
Check for a sticking choke, clogged air cleaner,
or a carburetor
problem - float level high, defective needle or seat, etc.
This may also be
attributed to weak ignition voltage,
an inoperative preheating system
(carburetor intake air), or extremely low cylinder compression.
WORN
This
plug has served its useful life and should be replaced.
The voltage required
to fire the plug has approximately doubled
and will continue to increase with
additional miles of travel.
Even higher voltage requirements, as much as 100%
above normal,
may occur when the engine is quickly accelerated.
Poor
engine performance and a loss in fuel economy are traits of a worn spark