KTM LC4 400-660LC42003 engine. Manual - part 14

7-19D

Check of EPC system microswitch

NOTE: The microswitch is arranged on the left side of the constant-
depression carburetor in the area of the throttle valve. If the throttle
valve is opened all the way, the microswitch will close the power circuit.

– Remove seat and tank.
– Disconnect the 2-pole plug

of the microswitch.

– Connect an ohmmeter to both terminals of the microswitch.

– With the throttle valve closed, the ohmmeter must indicate zero

continuity.

– Open throttle valve all the way by twisting the throttle grip as far as

possible. In this case, you will hear a slight clicking noise of the
microswitch. In this position, the ohmmeter must indicate conductive
continuity.

Replacing the EPC system microswitch

– Remove seat and tank.
– Disconnect the microswitch plug.
– Remove the 2 screws

, and take off the microswitch.

– Apply Loctite 243 to the threads of the two screws.
– Position the new microswitch, and fasten it with the two screws.
– Connect the plug, mount tank and seat.

Check of idle switch / contact screws

NOTE: The contact screw having the cable colors black/blue closes the
contact, when the 2nd gear is engaged.

The contact screw having the cable colors black/orange closes the
contact, when the 3rd gear is engaged.

The contact screw having the cable colors black/green closes the
contact, when the idle gear is engaged.

– Before you start with the check, disconnect the plug-and-socket

connection

to the EPC controller.

– For checking of the contact screws, connect a test lamp to the

positive terminal of the battery.

– Touch the connection of the central contact screw

with the test

probe. With the transmission set to idle, the test lamp has to be lit.

– When a gear is engaged, the test lamp must cease to be lit.

– Shift to 2nd gear, and touch the connection of the lower contact

screw

with the test probe. The test lamp must light up.

– With the transmission set to idle, the test lamp must not be lit.

– Shift to 3rd gear, and touch the connection of the upper contact

screw

with the test probe. The test lamp must light up.

– With the transmission set to idle, the test lamp must not be lit.

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-20D

Charging system

Generator

Regulator-rectifier

Main fuse (20 A)

Battery (12V / 8 Ah)

Capacitor

Leakage inspection

The drop test must be performed before checking the voltage
regulator/rectifier
– Turn off the ignition and disconnect the ground wire from the

battery.

– Insert an amperemeter between the ground wire and the negative

pole of the battery.

Setpoint value: max. 1 mA

– Check for power consumers, should the measured value exceed the

indicated maximum value.
Example:

● defective voltage regulator-rectifier

● leak currents in the socket connectors, in the ignition lock or in the

starter relay.

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

0,00

ignition

lock

start

relay

tachometer

CDI

ge-r

s-r

r-s

ELECTRICAL – DUKE-E

7-21D

Charging voltage / checking the voltage regulator-rectifier

NOTE: The values stated below apply only to fully charged batteries
(minimum charging level 90 %).

– Start the engine and switch on the low beam.
– Connect a voltmeter to both battery connections.
– Accelerate the engine to a speed of 5000 rpm and read off the

voltage.

Nominal value: 14.0 - 15.0 V

In the case of a significant deviation from the nominal value:
– Check the connector between the stator and the voltage regulator-

rectifier and the connector between the voltage regulator-rectifier
and the cable tree.

– Check the stator.
– Replace the voltage regulator-rectifier.

Removing the battery

– Remove the seat.
– Disconnect first the negative and then the positive pole of the

battery.

– Remove the bolts

and swing the battery support with the voltage

regulator-rectifier sideways.

– Remove the battery.
– When reinstalling the battery, connect the negative pole last.

CAUTION

OLLOW THE INSTRUCTIONS OF THE MANUFACTURER WHEN FILLING A NEW BATTERY

HE RELEVANT SAFETY INSTRUCTIONS ARE ALSO CONTAINED IN THE USER MANUAL

SUPPLIED WITH THE BATTERY

Charging the battery

– Remove the battery and check the charging level. Use a voltmeter to

measure the voltage between the battery poles (off-load voltage).

– Accurate results can only be obtained if the battery has neither been

charged nor discharged during a period of 30 minutes preceding the
measuring.

– If the battery is empty, it can be recharged for a maximum period of

10 hours at 0.8 A and a maximum of 14.4 V.

CAUTION

– T

O AVOID DAMAGE

DO NOT REMOVE THE LOCKING BAR

– A

LWAYS CONNECT THE BATTERY TO THE CHARGING UNIT BEFORE TURNING THE

CHARGING UNIT ON

– W

HEN RECHARGING THE BATTERY IN CLOSED ROOMS ENSURE SUFFICIENT

VENTILATION

. E

XPLOSIVE GASES ARE RELEASED DURING THE BATTERY CHARGING

PROCESS

– C

HARGING TIME AND CHARGING VOLTAGE SHOULD NOT EXCEED THE STATED

VALUES

. O

THERWISE ELECTROLYTE WILL BE RELEASED THROUGH THE SAFETY

VALVES

– A

VOID QUICK CHARGING IF POSSIBLE

off load voltage

charging level

charging time charging voltage

Volt

0.8 A

>12.7

100

––

~12.5

4 h

max.

~12.2

7 h

14.4 V

~12.0

11 h

~11.8

14 h

Repair manual KTM LC4

Art.-Nr

. 3.206.006 -E

7-22D

Checking the capacitor

– Pull main fuse out of the fuse holder.
– Discharge the capacitor by bridging the two terminals with a

screwdriver and remove.

– Connect the negative pole of a 12V battery with the negative

terminal of the capacitor. The connection between the positive pole
of the battery and the positive terminal of the capacitor (marked +)
is made with a test lamp

– When the power circuit is closed, the test lamp must begin to light

up. As capacitor charging increases, the brightness of the test lamp
must decrease.

– The test lamp must go out after 0,5-2 seconds (depending on the

lamp capacity).

– If the test lamp does not go out or does not light up at all, the

capacitor is faulty.

CAUTION

ISCHARGE THE CAPACITOR BEFORE AND AFTER EACH TEST

HEN

INSTALLING

THE

CAPACITOR

MAKE

SURE

THAT

THE

TERMINALS

ARE

CONNECTED IN ACCORDANCE WITH THEIR MARKINGS

. C

ONNECT RED

WHITE CABLE

TERMINAL

7-23D

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

7-24D

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.

7-25D

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

7-26D

Checking the starter relay

– Remove the seat and the right side cover and disconnect the

combination connector

of 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?

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

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