KTM Duke 390 Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
Hello, I've been having some issues with my Duke 390. The magnet in my alternator broke off and damaged the stator so I had to replace both. After replacing both parts I started experiencing headlight issues, low beam started burning out after a short period of time, when I switched to high beam it would also burn out very quickly. I tried replacing the bulb thinking it was faulty, but the new one also died. I disconnected the headlight and measured the voltage and it was reading 14V on both low and high beam connector, after that I checked the battery charging voltage as instructed by the service manual and at idle or @5000rpm it stayes in the 13.5-15V range so I eliminated the alternator and the voltage regulator being the issue. As I disconnect the stator to check for alternator winding just to be sure, I checked the voltage again on the headlight connect and it was just under 12V. Could the stator be the problem?
 

·
Registered
2015 duke 200, Previous bike (2009 er6n Kawasaki, 1982 honda nighthawk cb450)
Joined
·
83 Posts
Sounds like your doing a good job diagnostics. It is possible the fuses are issue. I'd assume that headlights are getting too much power. Perhaps the problem only presents itself at speed when riding. Another possibility is dirty connection. Any update about the issues?
 

·
Administrator
Joined
·
2,536 Posts
The problem is most likely the Stator or the Regulator/Rectifier.
Did you have the stator re-wound or is it an OE new one?
Did you have to plug the pins into the connector or did the stator come with the connector in place?
Always a challenge these electrical gremlins.

Hello, I've been having some issues with my Duke 390. The magnet in my alternator broke off and damaged the stator so I had to replace both. After replacing both parts I started experiencing headlight issues, low beam started burning out after a short period of time, when I switched to high beam it would also burn out very quickly. I tried replacing the bulb thinking it was faulty, but the new one also died. I disconnected the headlight and measured the voltage and it was reading 14V on both low and high beam connector, after that I checked the battery charging voltage as instructed by the service manual and at idle or @5000rpm it stayes in the 13.5-15V range so I eliminated the alternator and the voltage regulator being the issue. As I disconnect the stator to check for alternator winding just to be sure, I checked the voltage again on the headlight connect and it was just under 12V. Could the stator be the problem?
 

·
Registered
Joined
·
875 Posts
Head lamp fusing out is mainly due to one reason, excessive voltage to the bulb. A faulty stator can sometime read good on a multimeter, but might internally have a short and might have taken the rectifer along. Make sure you carry out a resistance value check on both the stator and regulator/rectifier. Secondly, make sure the headlamp unit, bulb connector wires are not crimped, kinked or nicked as they can cause a short. I would strongly err towards a faulty stator or faulty RR. Good luck..
 
1 - 4 of 4 Posts
Top