Ignition Coil - Buell S1 Lightning Workshop Manual

GENERAL
The ignition coil is mounted on the frame underneath the fuel
tank and behind the steering neck.
See Figure 7-9. The ignition coil (13) is a pulse-type trans-
former. Internally, the coil consists of primary and secondary
windings with a laminated iron core. The contents are sealed
in a waterproof insulating compound. The ignition coil is not
repairable. Replace the unit if it fails.
The low-voltage ignition primary circuit consists of the coil pri-
mary winding, ignition module (23) and battery. When the cir-
cuit is closed, current flows through the coil primary winding
creating a strong magnetic field in the iron core of the ignition
coil.
When the ignition module receives a signal from the ignition
sensor plate (8) and trigger rotor (9), the ignition module inter-
rupts (opens) the ignition primary circuit, which causes the
magnetic field in the coil core to collapse suddenly.
The collapsing magnetic field induces a high-voltage electri-
cal discharge in the ignition secondary circuit, which consists
of the coil secondary winding, spark plug cables and spark
plugs (12). The high-voltage discharge produces a spark to
bridge the electrode gap of each spark plug.
The ignition coil fires both spark plugs simultaneously. In one
spark plug, the spark jumps from the center electrode to the
outer electrode, but on the other plug, the spark jumps in the
reverse direction (from the outer electrode to the center elec-
trode).
TROUBLESHOOTING
Follow the troubleshooting procedures listed under
SYSTEM if the engine will not start, is difficult to start or runs
roughly. Also check condition of spark plug cables. Insulation
on cables may be cracked or damaged allowing high tension
current to short to metal parts. This problem is most notice-
able when cables are wet.
If poor starting/running condition persists, check resistance of
ignition coil primary and secondary windings using an ohm-
meter. See Figure 7-11. Resistance values should be within
the limits shown in Table 7-3.
7-16

IGNITION COIL

dyn808
Ignition coil primary
Ignition coil secondary
Figure 7-11. Test Ignition Coil Resistance Tests
Table 7-3. Ignition Coil Winding Resistance
IGNITION COIL
WINDING
Primary
Secondary
IGNITION
A low resistance value indicates a short in the coil wind-
ing-replace coil.
A high resistance value might indicate that there is some
corrosion/oxidation of the coil terminals. Clean the termi-
nals and repeat resistance test. If resistance is still high
after cleaning terminals, replace coil.
An infinite ohms ( ∞ or no continuity) resistance value
indicates an open circuit (a break in the coil winding)-
replace coil.
circuit test
circuit test
OHMMETER NORMAL RESISTANCE
SCALE RANGE (IN OHMS)
RX1 2.5-3.1
RX1K 10,000-12,500
NOTE