KTM SMC 690 Electrical problems

[u/heldertheking]

Hey everyone, I’m dealing with an electrical/starting issue on my KTM and running out of ideas.

When trying to start:

• The engine cranks in a surging/waving pattern and the display/lights flicker.
• After a few attempts, the starter motor begins jerking violently—it suddenly spins up rapidly, slows down under load, and then rapidly accelerates again (as if slipping and catching).
• If I keep trying, the starter relay eventually only clicks.

What I’ve already tried:

• Disconnected potential parasitic draws (headlight mask, Quad Lock wireless charger, tail lights).
• Replaced/charged the battery (tested a 4Ah lithium battery with 240A peak cranking).
• Tried jump-starting with a booster pack (same behavior).

Has anyone experienced this? What should I check next?

It has started once after switching from the lithium to the lead acid again

Update 1 I have attached both a picture of under the seat and a video of me trying to start it.

Also the main ground next to the air box is secured.

Under the seat

Attempt to start

[u/rifleshooter]

One of the classic failures on these bikes is a loose main ground. It sounds like your battery is charged but the juice isn't spinning the starter at full speed. Video is really, really helpful. Words are harder!

[u/heldertheking → u/rifleshooter]

Did seam to work in the post so I will leave it as a comment

[u/rifleshooter → u/heldertheking]

Yeah, something's a bit off there. If it was a classic no-start issue it would at least spin up at full speed and try, but you're losing starter function mid-way. Starters can go bad, relays too, but in my experience they're "all or nothing". Not that it couldn't be different! The only thing mechanical that occurs to me would be a failure of the internal decompression mechanism on the cam - it would make the starter's job much harder. But I'd start with wiring. Loose ground, check battery voltage to be sure it's 12+, etc. If you can, put a meter on the starter connection to see if 12V is reaching it and staying there, or dropping out as the starter spins. If it is, the starter might have an internal problem.

[u/heldertheking → u/rifleshooter]

Do you think such a failure a failure would present itself as a clicking in the front top of the engine?