I have a 2022 KTM 350SXF that is refusing to start for me. This past Saturday I went to the MX track and my bike wouldn’t start at all. Just a single click when I would press the starter button. I took off the seat, jiggled some wires, cleaned the battery posts the best I could and then it started right up. I figured it was corroded posts on the battery and I’d take care of it when I got home. I rode all day with no issues.
Come Monday I want to do an oil change so I go to prime the bike and then start it. Again, a single click, so I cleaned the battery posts, the ground to the frame, and cleaned out as many connectors that are to be found under the seat. Still one single click from the solenoid. I tested the battery, original to the bike, and it tested fine, but I went ahead and ordered a new battery from FirePower and a new KTM starter solenoid. This should do the trick. Btw, the 10a fuse is still in one piece.
Now it’s Wednesday night, I installed the new parts and still a damn single click. I cleaned out the starter button, cleaned the kill switch, cleaned the starter terminal, cleaned out more connectors, double check if there’s any broken wires and nothing that I see. Lastly I took the starter off to test and it spins freely.
I have NO idea where to go from here. All help is appreciated!
Does the fuel pump prime still? Or just click and all dead?
Checked wires behind number plate?
I would also check starter button and kill switch.
Have you tried bump starting? (To rule out starting system issues)
No prime, just a single click.
I’m going to go through the wires thoroughly after work tonight.
I hate bump starting but I’ll give it a whirl. 😂
Electrical problems are the worst. The troubleshooting needs to be systematic otherwise it's easy to chase your tail.
That the starter relay is clicking audibly and not starting means low voltage is happening at the relay but not full voltage making its way to starter, or the starter motor is intermittently faulty. That you jiggled wires under the seat and the bike started most likely points to a faulty connection or a broken wire somewhere and not the starter motor.
AI might be helpful for further troubleshooting exactly where that fault is occuring. It is AI so take the below with a gain of salt but at least you'll have some systematic things to guide your testing. The prompt for the below mentioned your specific model year bike and the backstory you provided.
1. Battery Load Test (5 min)
Multimeter on DC volts: Probe battery terminals at rest (>12.6V good).
Hold starter button 5 seconds—voltage must stay >10V; below confirms weak cell or cable resistance despite "good" static test.
Fail? Charge fully or replace cables before proceeding.
2. Main Fuse & Relay Input (5 min)
Confirm 10A fuse intact (pull/inspect).note you visually inspected but test with multimeter)
Probe relay small input wire (usually black/red): 12V+ with run/stop on RUN.
Large battery input post on relay: 12V+ steady. No voltage? Trace back to battery positive cable corrosion.
3. Relay Bypass Test (3 min)
Locate relay (under seat near battery). Identify two large posts: #1 battery positive in, #2 starter output.
Heavy screwdriver across both posts (spark normal)—starter must spin freely strong.
Spins: Relay contacts bad (even new)—replace relay.
No spin: Fault in starter cable, ground, or motor
4. Ground Circuit Check (5 min)
Battery negative to frame: Clean to bare metal, measure resistance (<0.2 ohms).
Frame to engine case: Same test.
Voltage drop test: Negative probe on battery -, positive on starter housing while cranking (<0.5V good).
5. Starter Feed Cable (5 min)
Follow thick red cable from relay output post to starter input terminal.
Tighten both ends. Check for frays/chafing near frame
Voltage at starter input post while cranking: Must hit 12V on relay click—if drops, cable resistance.
6. Control Circuit Quick Check (3 min)
Run/stop switch: Multimeter continuity across terminals in RUN (infinite resistance in STOP).
Starter button: Continuity when pressed. Clean spray if sticky.
Decision Tree
All voltages good + relay bypass works = bad relay contacts.
Bypass fails but starter spins freely off bike = starter cable/ground.
Battery drops under load = sulfated battery despite new one.
Thank you. I will start from the beginning. You're right, I will start to chase my tail here shortly and drive myself insane.
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Disconnect the tip over sensor and re connect as well as the ecu
I didn't know dirt bikes had tip over sensors?😂 I had to look it up and figure out where it's at. I'll try that too. Can't hurt any.
I did disconnect the ECU and cleaned out the plugs last night, but no luck.
Bro we are standing by.
Ok, here's the update. I took apart every connector, cleaned them, very small amount of dielectric grease applied, and cleaned the starter post real well. Still just a click. Dammit. On another forum someone said, check your tip over sensor, who knew a dirt bike has a tip over sensor? After digging it out and cleaning the connector I noticed the brown wire had a small slit in it and I could see copper. I fixed that and still just a click. WTF! The one thing I did not do, was clean the surface well on the subframe for the ground from the battery. I kind of cleaned it with my finger, but this time I took my grinder to it and got shiny aluminum again. Probably the wrong thing to do, but I can't say it's dirty or corroded anymore. I hooked it all back up and the damn thing fired up. So I don't know if that was the true issue or I wiggled something into place temporarily. I'm still not confident, but she fired up several times. I even wiggled wires around seeing if it would just do one click again, but it kept starting up. No idea, I hate electrical, and I'm going back to a early 2000's two-stroke. 😂
I'm going back to a early 2000's two-stroke...
For general knowledge about KTM products. When reviewing a similar issue, I found this situation. I have a ‘24 KTM 500 EXC. In 2024 with about 5 hours of run time, the starter would engauge but not turn over the motor. It would produce kind of a ugh groan. After hitting the button several more times it always started. Mind you this is the newest generation of starting sequence. The ECU is not energized until the starter button is pushed. The research and trials to identify the issue were exhaustive. In the end a warranty review by the dealer identified the decompression mechanism on the cam shaft was coming apart. Good thing I did not operate to failure.
Nice hear you located the sensor and found bare wire
I ran a ground from the battery to under the tank on my 2017 SXF450 and it fixed the grounding problem. There were other electrical things that drove me crazy, but systematically traced and fixed everything. I'm going to sell my '24 FC450 before 70 hours so I don't have to do all that again.
The kill button wire connector is behind the front number plate. They are notorious for corroding and causing your very issue. If nothing else it is good to check on a regular basis. I've replaced 2 kill buttons on my 17 FC450 to fix this. It drove me nuts for a while until I saw how simple the fix is.
I did clean all the connectors and cleaned the negative cable connection to the subframe. No issues since. 🤙
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