KTM LC4 400-660LC42003 engine. Manual - part 16

7-35D

bl  . . . . . . . . .blue
br  . . . . . . . . .brown
ge  . . . . . . . .yellow
gr  . . . . . . . . .grey
g   .  . . . . . . . .green
o  . . . . . . . . .orange
r   .  . . . . . . . . .red
ra  . . . . . . . . .pink
s . . . . . . . . . .black
v  . . . . . . . . .violet
w  . . . . . . . . .white

Battery

Ignition lock

Emergency off switch

Auxiliary relay

Tip switch built in emergency off switch

Neutral switch

Clutch switch

Start relay

Starter motor

ge-r

ge-bl

g-s

Electric starter system

The system is equipped with a safety mechanism. Electric starting is only
possible when

● the ignition lock is in the position
● the emergency OFF switch is in the position
● the transmission is switched to neutral or the clutch is pulled.

Function of the electric starter system:
From the battery

the battery voltage is transmitted via the ignition

lock

and the emergency OFF switch

to the coil of the auxiliary

starting relay

and to the tip switch

The contact of the auxiliary starting relay prevents starting unless at
least one of the following requirements is met :

● The transmission must be switched to neutral (neutral switch

closed).

● The clutch must be pulled (clutch switch

must be closed).

When the tip switch

is operated, the starter motor

is switched on

via the starter relay

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-36D

Check start auxiliary relay

– Remove headlight mask and remove the start auxiliary relay (cable

colours red and red-white).

– Connect the start auxiliary relay to a 12 V battery as shown in the

illustration.

– Use an ohmmeter to measure the continuity between the terminals

and

Reading 0 Ω relay intact

Reading ∞ Ω relay defect

Checking the auxiliary starting relay for faultless
operation

Preparation:
– Connect an ohmmeter or a continuity tester to the cables of the

auxiliary starting relay (colors: red and red/white).

– Perform the tests in the order indicated below. The auxiliary starting

relay must respond in either of the following two cases:

● Put in a gear and slowly pull the clutch lever. The auxiliary starting

relay should respond when the lever is pulled approximately half of
the overall distance. If this is not the case, please check the clutch
switch. Keep an eye on the neutral control lamp while performing
this test. The neutral control lamp should not light up. If it lights up,
check the diode with the cable colors yellow and green/black.

● Switch the transmission to neutral without previously pulling the

clutch. The auxiliary starting relay should now connect and be
tripped as soon as a gear is put in. If this is not the case, please
check the diode in the connector with the cable colors yellow and
green/black and the neutral switch.

NOTE: Connecting of the auxiliary starting relay is always accompanied
by a faint clicking sound. The ohmmeter or continuity tester indicates
continuity while the auxiliary starting relay is on.

7-37D

Checking the diodes

NOTE: Diodes conduct current only in the direction indicated by the
arrow, preventing the conduction of current in the opposite direction.

Two different kinds of diode defects can be distinguished:
– The diode conducts no current at all.
– The diode conducts current in both directions.
Diode defects can lead to different kinds of trouble, depending on the
type of defect.

NOTE: Both diodes are the same type and require the same testing
procedure. They are each located in a 2-pole connector and can be
identified by the color of the cables leading up to and away from the
respective connector.

Checking the diodes for faultless operation:
– Remove the headlight mask.
– Pull the diode to be tested out of the connector.
– Connect an appropriate ohmmeter to the diode and check for

continuity.

– Connect the ohmmeter in the opposite direction and check if the

diode prevents current conduction in the opposite direction.

Checking the clutch switch

– Disconnect the clutch switch from the cable tree.
– Connect the ohmmeter to the 2-pole connector

(cable colors:

yellow/yellow) of the clutch switch and slowly pull the clutch lever.

– The switch must connect when the lever is pulled approximately half

of the overall distance.

Checking the tip switch and the emergency off switch

– Remove the headlight mask.
– Disconnect the 4-pole connector

of the tip switch/emergency OFF

switch from the cable tree.

– Use an ohmmeter and test both switches according to the table

below (please refer to the sketch for the configuration of the
connector).

– Then check all lines for ground contact.

starter

tip

switch

emergenc

y off

switch

Circuit

Position

Condition

Emergency off switch

duct

Emergency off switch

no duct

Tip switch

operated

duct

Tip switch

not operated

no duct

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-38D

Checking the starter relay

– Remove the seat and disconnect the combination connector

the starter relay.

– Disconnect negative terminal at battery and the two cables at the

starter relay.

– Connect the starter relay to a 12 V battery as indicated in the

diagram.

– Check continuity between terminals

and

using an ohmmeter.

Reading: 0 Ω OK

Reading: ∞ Ω defect

NOTE: The response of the starter relay is accompanied by a faint
clicking sound.

Checking the electric starter motor

– Switch off the ignition.
– Disconnect the negative pole of the battery and remove the electric

starter motor.

– Connect the negative pole of a 12 V battery to the housing of the E

starter motor and briefly connect the positive pole of the battery to
connection

of the electric starter motor (use thick cables).

– The starter must turn as soon as the circuit is closed.
– If this is not the case, replace the starter.

Checking the neutral switch

– Remove the chain cover.
– Connect one terminal of a test lamp to the positive pole of the

battery and the other to connection

of the neutral switch.

– The test lamp must light up when the transmission is switched to

neutral.

– The test lamp must go out as soon as a gear is put in.

Trouble shooting in the electric starter system

When the starter motor fails to turn upon operation of the tip switch,
perform the following checks first:

● Is the ignition lock switched to ?
● Is the emergency OFF switch in the position ?
● Is the neutral control lamp on while the ignition is on?
● Can the engine be started with the clutch pulled?
● Is the battery charged?
● Has the main fuse blown?
● Has the fuse under headlight mask blown?

● Check the auxiliary starting relay
● Check the starter relay
● Check the starter motor

7-39D

Ignition system

From the battery

the battery voltage is conducted via the main fuse

through the ignition lock

and the emergency OFF switch

which are both ON, to the side stand relay

The side stand relay conducts the battery voltage to the CDI unit

, if

at least one of the following requirements is met :

● The side stand is up (side stand switch closed).

● The transmission is switched to neutral (neutral switch closed).

● The clutch is pulled (clutch switch closed).

The pulse generator

transmits a signal to the CDI unit

upon every

rotation of the crankshaft. In the CDI unit, the ignition point is
computed from this signal.
The ignition pulse is transmitted to the ignition coil

(i.e. an ignition

spark is generated).

NOTE: The ignition system is a digital high voltage capacitor ignition
that receives its power supply from the battery. Therefore, it works only
with an intact battery.
When the battery is discharged below the threshold level, the voltage
can, due to the starting process, drop below the minimum supply
voltage required by the ignition.

CAUTION

AFE AND FAULTLESS OPERATION OF THE DIGITAL IGNITION REQUIRES SPARK PLUG

CONNECTORS AND SPARK PLUGS WITH INTEGRATED RESISTANCE TYPE SUPPRESSORS

Battery

Main fuse

Ignition lock

Emergency-off switch

Auxiliary relay

CDI

Pulse generator

Ignition coil

Side stand switch

ge-bl

s-r

r-s

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-40D

CDI unit

Check the cables and plug and socket connections of the CDI unit

The CDI unit function can only be checked on an ignition test bench.

CAUTION

EVER USE A COMMERCIAL MEASURING DEVICE TO CHECK THE

CDI

UNIT

OMMERCIAL MEASURING DEVICES CAN DESTROY HIGHLY SENSITIVE ELECTRONIC

COMPONENTS

Check ignition coil

– Disconnect all cables and remove the spark plug connector.
– Use an ohmmeter to measure the following values.

NOTE: The indicated setpoint values correspond to a temperature of
20° C.

Replace the ignition coil if the measured values deviate significantly
from the setpoint values.

Spark plug connector

– Check the spark plug connector for cracks and fissures.
– Measure spark plug connector resistance.

Setpoint value: 3.0 – 7.5 kΩ

Checking the side stand relay

Preparation:
– Remove the seat, the right side cover. Swing the headlight mask

forward.

– Disconnect the power supply from the CDI (orange cable).
– To check the current status of the relay connect the orange cable

coming from the cable tree either to the positive line of a voltmeter
or to a test lamp.

– The negative line of the voltmeter or test lamp is connected to

ground.

– Switch on the ignition lock and the emergency OFF switch.

Perform the following tests in the order indicated below:
– The relay must connect in either of the following three cases:

● Put a gear in but do not pull the clutch. Slowly swing up the side

stand. When the side stand is approximately halfway up, the side
stand relay should respond. If this is not the case, please check the
relay, the side stand switch

as well as the corresponding parts of

the cable tree.

● With the side stand down and a gear put in, slowly pull the clutch

lever. The side stand relay should respond when the lever is pulled
approximately half of the overall distance. If this is not the case,
please check the diode in the connector with the yellow and the pink
cable and the neutral switch.

● With the side stand down and the clutch not pulled, switch the

transmission to neutral. The relay should connect when the
transmission is switched to neutral and be tripped when a gear is
put in. If this is not the case, please check the diode in the connector
with the yellow and the green/black cable and the neutral switch.

NOTE: Responding of the relay is accompanied by a faint clicking sound
and the CDI’s power supply is switched on. The voltmeter or the test
lamp indicates a battery voltage. After testing, reconnect the CDI unit’s
power supply (orange cable).

RESISTANCE

0,425 – 0,575 Ω

10,80 – 16,20 kΩ

MEASUREMENT

primary coil

secondary coil

COLOURS

blue/white – ground

blue/white – ignition wire

7-41D

Checking the side stand switch

– Disconnect the 2 connectors connecting the side stand switch

with the cable tree (below the tank).

– Connect an ohmmeter to the side stand cable.
– Slowly swing up the side stand.
– The switch must be open while the side stand is down.
– The side stand switch must connect when the side stand is

approximately halfway up.

– If this is not the case, replace the side stand switch.

CAUTION

EVER SHORT

CIRCUIT THE SIDE STAND SWITCH SO AS TO BE ABLE TO DRIVE ON

HIS WOULD DEACTIVATE THE IGNITION CUT

OFF WITH THE SIDE STAND DOWN

AND YOUR MOTORCYCLE WOULD NO LONGER COMPLY WITH THE APPLICABLE
SAFETY STANDARDS

NOTE: If the side stand is removed, for example when subsequently
installing a center stand, the two connectors of the cable tree that lead
to the side stand switch must also be connected.

Trouble shooting in the ignition system

Before checking the ignition system check
● if the ignition lock is in position
● if the emergency off switch is in the position
● if the neutral control lamp is on
● if the motorcycle can be started with the clutch pulled
● if the battery is charged
● the main fuse and the fuse under the headlight mask

Check if an ignition spark is produced when the starter is operated.
Proceed as follows:
– Pull the spark plug connector.
– Disconnect the spark plug connector from the ignition cable.
– Hold the free end of the ignition cable approximately 5 mm from

ground.

– A strong spark should be visible when the electric starter is now

operated. If the battery is discharged below the threshold level
required for electric starting, please use the kickstarter.

– If a spark is visible, replace the spark plug connector.
– Twist out the spark plug and insert it into the spark plug connector.
– Connect the spark plug to ground. A strong spark should be visible

at the electrode when the electric starter is now operated. If this is
not the case, the spark plug connector or the spark plug is defect.

– If no spark is produced during the first test, perform the following

checks:

● Does the ignition’s power supply line (orange) carry battery voltage?

● If this is not the case, check the ignition lock, the emergency off

switch and, if applicable, the side stand relay as well as the
corresponding parts of the cable tree.

– If the ignition is sufficiently supplied with power and no spark is

produced, check:

● ground connection of CDI unit and ignition coil
● the cable between CDI unit and ignition coil
● pulse generator
● stator
● ignition coil

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-42D

DYNAMIC GENERATOR VALUES 400/640 LC4-E / 625 SXC (KOKUSAN 4K-2)

Measuring conditions:
– remove seat (also side trim and left side cover for Racing model)
– all connectors and the ground connection in a non-corroding condition, connectors tightly connected
– battery in a startable condition, not fully loaded (start several times for fully loaded battery)

Regulator rectifier output – measure the voltage with the measuring
leads of the peak voltage adapter directly on the poles of the vehicle
battery:

– unstressed and stressed for the entire speed range

Multimeter display: 14 volts +/- 1 volt

NOTE: The black measuring lead on the peak voltage adapter should be
applied to the ground (negative terminal).

Check the charge current – remove main fuse, apply the multimeter
measuring leads (without the peak voltage adapter) to both connectors
on the fuse carrier

and measure the current (set the multimeter DCA

to 10 amperes):

– Unstressed (no electric consumer switched on), engine running at

idle speed (1400 +/-50 rpm)

Multimeter display: 6 amperes +/- 0.1 ampere

– Stressed (light switched on, horn and brake actuated), engine

running at idle speed

Multimeter display: 0 amperes +/- 0.1 ampere

– Stressed (light switched on, horn and brake actuated), engine

running at increasing speed (up to 8000 rpm)

Multimeter display: 2 amperes +/- 0.1 ampere

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