Resurrecting a 2003 KTM 450 SXF !!!

I purchased a non running 2003 KTM SXF for $1200. YES $1200. It was a gamble. The bike had a cracked cylinder that leaked antifreeze into the combustion chamber, it had no spark from a dead CDI ignition box, the rear wheel including hub, spokes, rim, and tire were poo poo. It was completely shot. This took a few months to get going. Fun fact- I purchased this bike with in 24 hours of FFS Tom getting his MXC 250.
OEM parts purchased from KTM WORLD! Highland park off-road resort!
www.ktmworld.com

[@ffsdirtbike]

@3:32 I look back to make sure the rear wheel was spinning and not the clutch slipping. The KX 125 never broke the rear tire free going down a trail .

[@ffsdirtbike]

Fun fact:The brand new rear tire seen in this video lasted five weeks.

[@firdousesafar4531]

Hi I also have a 2003 KTM 450 EXC. when I purchased the bike it worked fine but after an hour of riding it the stator failed. I brought it to a mechanic and he got it running again but electric start wouldn’t work. Only kick, and this thing has crazy compression, almost pulled my leg trying to kick it. Anyways, I decided to strip the bike and rebuild it and powder coat the frame. The wiring was a nightmare from previous owners. Anyways, after bringing it to 5 different mechanics nobody can figure out the wiring harness until the last guy. He got the lighting harness to start working but whatever he did he couldn’t get any spark. He says he doesn’t know if it’s CDI or not. I assume not, since it was starting perfectly fine and giving spark before I stripped the bike. Anyways, if you can help that would be great. I’m located in Toronto Canada.

[@ffsdirtbike]

I’ll be glad to help. I’ve been in a facebook group called “ktm rfs owners riders fans” in this group you can have access to all wiring diagrams , test procedures and good advice from some members. If you haven’t yet I would suggest joining this group. I plan on making some more RFS videos soon. I get a lot of wiring questions and I’d like to go over what I know and also I have an upgrade stator and cooling fan for mine yet to install. Thanks for watching and I’ll try to help out if I can.

[@ffsdirtbike]

RFS Voltage Checks
Yellow wire feeds ac to the lights, white wire charges battery (via regulator/rectifier)
Checking the generator output
Measuring conditions:
- cold engine
- seat and tank removed
- all connectors and the ground connection in a non-corroding condition, connectors tightly connected
- battery loaded (if installed) and light switch turned off
- compression release lever pulled
- kick the kick starter forcefully at least 5 times for each measurement
Check the generator output for voltage between the following cable colors:
- between yellow and brown (ground), loom disconnected Multimeter display: 15 volts +/- 1 volt
- same measurement with loom connected
Multimeter display: 12 volts +/- 1 volt
- between white and brown (ground), loom disconnected Multimeter display: 19 volts +/- 1 volt
- same measurement with loom connected
Multimeter display: 14 volts +/- 1 volt
NOTE: The black measuring lead of the peak voltage adapter must be
applied to the ground.
Check regulator rectifier output voltage cable colors yellow/red, regulator rectifier bk connected,
capacitor disconnected (if installed) and fuse bm removed:
- between yellow/red and brown (ground)
Multimeter display: 14 volts +/- 1 volt
NOTE:
- The black measuring lead of the peak voltage adapter must be
applied to the ground.
- For facilitation of work, the regulator rectifier bk can be detached from the frame.
Checking the voltage regulator-rectifier
A defect voltage regulator can cause different kinds of trouble:
• No voltage in the circuit
In this case, the voltage regulator must be disconnected at idle speed.
The voltage regulator is defect if the power consumers now work properly.
If the power consumers are still not supplied with power, the switch,
the wiring harness or the ignition system must be checked for defects.
• Excessive voltage in the circuit
The bulbs burn out. In this case the voltage regulator must be replaced.
Checking the charging voltage
NOTE: The values stated below only apply 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 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 regulatorrectifier
and the connector between the voltage regulator-rectifier and the cable tree.
- Check the stator.
- Replace the voltage regulator-rectifier
Resistance checks:
Ignition Coil
Measure Cable colours Resistance
primary coil blue/white - ground 0.30 $ 15% secondary coil blue/white - ignition wire 6.30 k 20%
Stator
Ignition Measure cable colours Resistance
Pulser coil red - green 100 S 20 9
4K-3B (EXC)
Exciter black/red - red/white 15 2+ 3 S
Charge coil ground - yellow 0.65 8 + 0.15 g white - yellow 0.16 S # 0.03 S
Voltage checks
Measuring conditions:
- cold engine
- seat and tank removed
- all connectors and the ground connection in a non-corroding condition, connectors tightly connected
- battery loaded (if installed) and 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
Check the pulse generator for an output signal - two-pin connector
with green and red cable colors:
- Apply the red measuring lead to the green cable and the black measuring lead to the red cable, disconnect the CDI unit Multimeter display: 4.5 volts +/- 0.5 volt
- Same measurement with CDI unit connected
Multimeter display: 3 volts +/- 0.5 volt
Check the generator charging coil for ignition capacitor charge - two-pin
connector with black/red and red/white cable colors :
- Apply the red measuring lead to the black/red cable and the black measuring lead to the red/white cable, disconnect the CDI unit
Multimeter display: 30 volts (35 volts for 400 SX) +/- 5 volts
- Same measurement with CDI unit connected
Multimeter display: 200 volts +/- 10 volts
Check the primary voltage output for ignition coil control for output voltage (blue/white cable color):
- Apply the red measuring lead to the black/white cable (ground) and the black measuring lead to the blue/white cable, CDI unit and ignition coil connected
Multimeter display: 200 volts +/- 10 volts
This diagnostic flow chart page was written by a very smart very helpful tech. named Kevin Parker. You will find him in the RFS owners group I mentioned earlier. When you’re in the group, you can find all this paperwork under the “Files“ tab .