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-   -   The KTM Duke 390 Ownership Experience Thread (https://www.team-bhp.com/forum/motorbikes/138082-ktm-duke-390-ownership-experience-thread-397.html)

I think the chain slap has always been a part of the 390 package. My opinion on what causes it:

- different level of tautness at different points in a chain : put up your bike on a paddock stand and rotate the wheel. You will most likely see the chain "hop" at certain intervals. Usually caused by a tight chain linkage. Lot more pronounced at lower rpm than high

- rough idle : variation of the rpm in idle would suggest a rough idle. In my experience, every single 390 has it. On low rpm, this constant change in RPM can cause the chain to hop

My recommendation:

- don't worry too much about it. It's one of the unfortunate traits of what's overall an awesome motorcycle. Just keep your chain tightened and lubed properly and you should be fine
- try a different chain sprocket combo to see if the situation is any better. I think rolon makes a kit for dukes

All the best guys! Ride safe

Faced an issue with my Duke 390 recently. Specifically, the radiator fan failed. This was changed under warranty and i was only charged for the labour i.e INR 150.:)

The symptoms were (for the benefit of all)
- Initially i used to get a burning smell i.e. while starting the bike, something like when water is put on a hot surface like the silencer
- Then the low battery sign showed up (twice)
- Finally during a ride, i saw the high coolant temperature message and the bike shut down.

I let the bike cool down and took it to the service station immediately. They checked everything from the sensor, to the battery, etc. and finally it was narrowed down to a fan which was slowing down.

They have changed the fan. Have been running the bike for the last few days and thankfully no issues have cropped up till now.

Ride Safe
Regards
Ronald

It's either the water pump seals or the head gasket. My 2016 duke 390 had the same issue, so the pump seals were replaced. After the replacement, i had to top-up the coolant twice or thrice but nothing after that.

Thanks for the info, even mine is a June 2016 model. Did you notice milky coffee colored oil? Or white smoke? Or there was no symptom like me? How much time did the SVC take to fix the issue?
TIA!

I did not face any white smoke or starting issues, infact the bike was behaving totally normal. SVC took 2 hrs to replace the seals and fill the coolant again, a minor job. Get yourself a can of coolant for top-up as you will be needing it.

Good to know that its a quick fix, but how did they diagnose the issue? and how did they confirm that the gasket is ok? I know a few friends who got fixes done without proper diagnosis and the issues were back, ktm SVC's are famous for this!:D How did you engine oil look? bad seals result in coffee colored oil, did you notice this? I know I'm being a little paranoid here but in the past two months this is the fourth time I would be visting the SVC apart from my regular service for niggles!:Frustrati

The mechanic first took out the seals for inspection and found them to be in damaged condition. I didn't inspect the engine oil, but then the mechanic informed that the coolant was mixing it. As per the mechanic, Starting issues and white smoke are the symptoms of head gasket failure. Since i was not facing any issues, he did not check the head gasket. I was riding with the damaged seals for almost 8k kms, so you don't need to be paranoid. It's best you sit with the mechanic and get the job done, hardly takes half a day . 😀

One more issue with my bike now. The display started showing low battery since yesterday, I was baffled as I use the bike on a daily basis and it's just 11months old (12100kms). Went to the service centre, they charged the battery for a couple of hours and put it back. I went home, approximately 10kms from the service centre, and the low battery sign showed up again. I went to the local battery shop who services car batteries, he checked and said that the battery isn't charging when the bike is running. Now guys, what might be the issue here, do I need to worry ?

Check the stator coil. It might probably on it's way out. If found faulty, replace it asap or it'll simply fail and the motorcycle will not start in the middle of a ride as i've found out:D

It happened with me today, after filling fuel, the bike refused to start. Pushed it for some time,tried starting again and luckily it started. Now will be taking it directly to the service centre on Monday, planning to use my old buddy(honda unicorn) till then. And will the stator coil be replaced under warranty ?

Failed stator coil is the reason for your low battery issue. You can confirm it by checking the voltage across battery, if the voltage level decreases even when the bike is revved, then the stator coil is not giving out enough voltage to charge it.

Yes when the local battery guy checked the battery voltage, it wasn't increasing at all when revved, so will the stator coil be replaced under warranty ?

I don't know why a stator coil would fail unless it has some unsupported wiring connecting it to the wiring harness. It's just some coils of insulated wires which don't move.

The voltage regulator and rectifier (RR) on the other hand relies on diodes to do its job and it gets quite hot in the process. ( Alternating current produced by the alternator goes into it and direct current comes out of it. It throws away half of the current as heat in the process of doing this.)

Heat and diodes don't get along well and a failure of the RR resulting in no power getting to the battery and the rest of the motorcycles wiring is fairly common on many motorcycles.

If I had this problem and a mechanic told me he replaced my alternator stator I would be suspicious.
If he said he replaced the regulator/rectifier I would grumble and pay the bill.

As arizonajim said, could be the rectifier/regulator too. Particular batch of duke had weak stator coils, so i suspected it. Stator coil or rectifier, replacement will be done for free, if the bike is under warranty.

The ratting or buzzing that you hear from the front end is from the fuel tank cap. I had this issue in my bike. The culprit is that at around 4 to 5k RPM, especially, when you decel, the resonance causes vibrations which is mild but annoying. I found that it was caused by the fuel tank lid key flap. One solution is to use a small round neydymium magnet and place it underneath the keyflap so that it sticks to the lid, and doesn't move an inch, and it worked like a charm. No vibes whatsoever.

Buzzing and annoying mild frequency vibrations have always pestered the 390. One thing is the chain slapping against the chain runners/guides in the swingarm and providing a slapping sound. This is mostly due to loose chain. Too tight a chain and you run excess slack making "katakakak" sound when the bike is in motion.

As posted above, observe if the sound is coming from the front, if yes try the fuel cap mod. Lots of parts like connectors tap against the inside of the tank and produce a wide variety of buzzing sounds.

Since we are dealing with the RC, I just noticed, the battery lid of the RC 390 is notoriously prone to producing rattling sound. One solution is to use a good quality high tension spring to the lock mechanism, arrests the sound 100%
Loose spring means loose clamping action and it results in the infamous battery cover vibrations.

With respect to chain slackness.

What I would suggest is undo the slackness, clean your front sprocket. IF YOU haven't checked/cleaned the front sprocket, it's a good idea to check it out. Lots of crud and grime gets gooed up and do affect the chain motion.

Loosen > clean > relslack > check your chain guides/runners, replace if necessary > lube after a small ride. Keep us posted.

Cheers!
VJ