KTM LC4 400-660LC42003 engine. Manual - part 17

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s–g

s–g

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7-43D

Repair manual  KTM LC4 

Art.-Nr

.  3.206.006 -E

7-44D

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4

5

S

NOTE: Before performing a test with the peak voltage adapter, make
sure that the orange cable (battery voltage) is applied to the CDI unit
and the black and white/black cables are applied to the ground.

Check the pulse generator for an output signal – two-pin connector 

1

with green and white cable colors (also see circuit diagram on opposite
page):

– Apply the red measuring lead of the peak voltage adapter to the

green cable and the black measuring lead to the white cable, 
disconnect connector 

1

to disconnect the CDI unit 

2

.

Multimeter display: 7 volts +/- 1 volt

– Same measurement with CDI unit connected

Multimeter display: 4 volts +/- 1 volt

Check the generator phase for detection of the direction of rotation
three-pin connector 

3

with red/black and black/yellow cables (also see

circuit diagram on opposite page):

– Apply the red measuring lead of the peak voltage adapter to the

red/black cable and the black measuring lead to the black/yellow
cable, disconnect connectors 

3

and 

4

Multimeter display: 17 volts +/- 1 volt

– Same measurement with connectors 

3

and 

4

connected

Multimeter display: 12.5 volts +/- 0.5 volt

Check the primary voltage output for ignition coil control for output 
voltage – one-pin connector 

5

with blue/white cable (also see circuit 

diagram on opposite page):

– Apply the red measuring lead of the peak voltage adapter to the

ground and the black measuring lead 

S

to the blue/white cable, CDI

unit 

2

and ignition coil 

6

connected

Multimeter display: 220 volts +/- 10 volts

STATIC IGNITION VALUES 400/640 LC4-E / 625 SXC (KOKUSAN 4K-2)

Measuring conditions:
– cold engine
– seat, side trim and tank removed
– all connectors and the ground connection in a non-corroding condition, connectors tightly connected
– battery loaded, ignition switch to position 1 (without light)
– the gap between the rotor and pulse generator must be set to 0.75 mm
– compression release lever pulled
– kick the kick starter forcefully at least 5 times for each measurement

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3

7-45D

Repair manual  KTM LC4 

Art.-Nr

.  3.206.006 -E

7-46D

3

4

7

9

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

Check the generator output for voltage between the following cable

colors

– three-pin connector 

3

(also see circuit diagram on opposite page),

connectors 

3

and 

4

disconnected; this disconnects the regulator 

rectifier 

7

and the CDI unit:

– between black/yellow and red/black
– between black/yellow and yellow
– between red/black and yellow

Multimeter display: 17 volts +/- 1 volt

NOTE: The measuring leads of the peak voltage adapter can be
randomly applied.

Check generator output for voltage to ground – three-pin connector 

3

(also see circuit diagram on opposite page), connectors 

3

and 

4

connected; this connects the regulatorl rectifier 

7

and the CDI unit:

– between black/yellow and ground
– between yellow and ground
– between red/black and ground

Multimeter display: 12.5 volts +/- 0.5 volt

NOTE: The black measuring lead of the peak voltage adapter must be
applied to the ground.

Check regulator rectifier output voltage

8

- two-pin connector 

9

with

cable colors red and black/white disconnected, connectors 

3

and 

4

connected (also see circuit diagram on opposite page):

– between red and black/white (ground)

Multimeter display: 13 volts +/- 0.5 volt

Measuring conditions:
– cold engine
– seat, side trim and tank removed
– all connectors and the ground connection in a non-corroding condition, connectors tightly connected
– battery loaded, ignition switch to position 1 (without light)
– compression release lever pulled
– kick the kick starter forcefully at least 5 times for each measurement

1

2

3

4

5

7-47D

Repair manual  KTM LC4 

Art.-Nr

.  3.206.006 -E

7-48D

1

1

3

4

5

S

R

Check the pulse generator for an output signal – two one-pin
connectors 

1

with green and red cable colors (also see circuit diagram

on opposite page):

– Apply the red measuring lead of the peak voltage adapter to the

green cable and the black measuring lead to the red cable,
disconnect both connectors 

1

to disconnect the CDI unit 

2

Multimeter display: 4.5 volts +/- 0.5 volt

– Same measurement with CDI unit connected

Multimeter display: 3 volts +/- 0.5 volt

NOTE: On 625 SC-models one two-pin connector is used instead of the 
two one-pin connectors, the colors of the cable are the same.

Check the generator charging coil for ignition capacitor charge for an
output signal– two-pin connector 

3

with black/red and red/white cable

colors (also see circuit diagram on opposite page):

– Apply the red measuring lead of the peak voltage adapter to the

black/red cable and the black measuring lead to the red/white cable, 
disconnect connector 

3

to disconnect the CDI unit 

2

Multimeter display: 30 volts +/- 5 volts

– Same measurement with connectors CDI unit connected

Multimeter display: 180 volts +/- 10 volts

Check the primary voltage output

4

for ignition coil control (also see

circuit diagram on opposite page) for output voltage (blue/white cable
color):

– Apply the red measuring lead 

R

of the peak voltage adapter to

ground and the black measuring lead 

S

to the blue/white cable, CDI

unit 

2 

and ignition coil 

5

connected

Multimeter display: 180 volts +/- 10 volts

STATIC IGNITION VALUES 400/620/625 SC / 660 SMC (KOKUSAN 4K-3, 3C)

Measuring conditions:
– cold engine
– seat, right side trim and tank removed
– all connectors and the ground connection in a non-corroding condition, connectors tightly connected
– light switch turned off
– the gap between the rotor and pulse generator must be set to 0.75 mm
– compression release lever pulled
– kick the kick starter forcefully at least 5 times for each measurement

6

9

10

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7-49D

Repair manual  KTM LC4 

Art.-Nr

.  3.206.006 -E

7-50D

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8

10

S

STATIC GENERATOR VALUES 400/620/625 SC / 660 SMC (KOKUSAN 4K-3, 3C)

Check the generator output

6

(also see circuit diagram on opposite

page) for voltage between the following cable colors:

– between yellow and brown (ground), connector 

7

disconnected

Multimeter display: 15 volts +/- 1 volt

– between white and brown (ground), connector 

8

disconnected

Multimeter display: 19 volts +/- 1 volt

– Repeat both measurements with connector 

7

and 

8

connected.

The measured values should be the same.

NOTE: The black measuring lead of the peak voltage adapter must be
applied to the ground.

Check regulator rectifier output voltage

9

(also see circuit diagram on

opposite page, cable colors yellow/red), regulator rectifier 

bk

connected, capacitor 

bl

disconnected:

– between yellow/red and brown (ground)

Multimeter display:  14 volts +/- 1 volt

NOTE:
– The black measuring lead 

S

of the peak voltage adapter must be

applied to the ground.

– The regulator rectifier 

bk

is located on the right behind the side trim.

Measuring conditions:
– cold engine
– seat, right side trim and tank removed
– all connectors and the ground connection in a non-corroding condition, connectors tightly connected
– light switch turned off
– compression release lever pulled
– kick the kick starter forcefully at least 5 times for each measurement