Re: KTM Duke 390 - Ownership Reviews and Experiences

Hello everyone. Just got my membership and this is my first post. I've been reading reviews and troubleshooting tips on xBHP since ages and the discussions on this forum have helped me a lot with my bike issues. Thank you xBhpians.

Some info about my bike: Duke 390 2013 (first batch) with 16000 km on the odo. Used only for long Sunday highway rides (150-250 km). I'd say 99% highway use.
The only major issue was leaking front fork seals, which was changed at 14000 km. Also, new battery installed a year ago. Changed engine oil every 5000 km with Motul 7100 10w50. Run-in procedure was as per manual. Noticeable loss of power and increased vibrations after 12000 km.

I took the bike out last month after 6 months of inactivity and got the '0' speedometer and 'low' battery warning after about 100 km of riding.
Checked the rectifier and it was okay. Opened the engine cover and removed the burnt stator coil. Got the new part today after waiting for a week although the gasket is still not in stock.

Burnt Stator coil.



At this point I also decided to clean the throttle body and check the valve clearance. Got the throttle body out and looked inside the engine intake port and was pretty shocked to see so much carbon deposit on the 2 intake valves. Is this normal? Has anybody checked the intake valves? The exhaust valves are so clean in comparison.The throttle body itself looks to be in pretty good shape compared to what I've seen on youtube. Anyways, I've removed the engine off the bike and plan to clean the valve as well.

Intake valve Left


Intake valve Right


Exhaust Valves


Throttle body



Opened the valve cover and saw some wear on the cam lobes. What do you guys think? Is it normal wear? The Valve clearances for exhaust valves are LEFT- 0.2 and RIGHT - 0.15.The LEFT valve needs adjustment. The intake valves could not be measured because my feeler gauge has only 0.05 and 0.1 gauges and 0.1 gauge does not go through the gap. I've ordered new ones. Intake valves could be tight (ideal value : 0.08 - 0.12).

Intake Cam Lobes


Exhaust Cam Lobes


I've planned a few improvements for my bike once the engine work is done.
1. 2018 Front brake MC with adjustable levers.
2. EBC Double-H sintered brake pads
3. Engine ice coolant
4. Grip puppies foam grip
5. NGK Iridium spark plug
6. Motul 300v² 10W-50 Fully Synthetic Engine Oil

Re: KTM Duke 390 - Ownership Reviews and Experiences

I came across this problem while removing the clutch cable. If you check the pics in the service manual it is exactly as you mention it - 2 nuts on opposite ends. First I thought a nut was missing, then I saw 2 nuts on one end. I figured they made a mistake during assembly. But I guess it's the same for all the Dukes.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Yes, it's the same for all Dukes. I recommend every user to add a nut to the left side of the cable, which makes clutch adjustment a breeze and helps keep the cable in place.


Starting off with your cam lobes, both the cam lobes wear seem to be slightly on the higher side, the scoring is a cause for concern, though it will hold up for some time to come. Try touching the cam lobe face and see if you feel pitting like sensation when you rub your fingers, if yes, then it's not good. Secondly, your intake valves have severe carbon deposits behind them, this can in fact interfere with the incoming mixture, reducing their velocity and not enough charge. Normally, fuel intake valves need to open and close quickly and smoothly. Unfortunately, carbon deposits can interfere with their function, restricting air flow and leading to clogged fuel systems, as well as other problems.

I'd recommend you to replace your valves as a set, especially the intake valves, they seem to have severe carbon deposits. These can either be cleaned or replaced. If you don't have any trouble with the pick up and the valve-train, I'd strongly recommend a thorough clean of the intake and exhaust ports, with prime importance given to your intake port.

The intake clearance for the 390 (to be checked when the engine is cold)

0.08 to 0.12 INTAKE
0.13 to 0.17 EXHAUST

Lastly, the dreaded ZERO and the Low Battery Warning can be sometimes due to a failed battery and a busted stator. If you observe speedo going 0 for no reason, it's a prime candidate for a busted stator.

Hope it helps!

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

Hello guys, great informative thread is going here with some really knowledgeable guys. I really appreciate expert helping out each other. I am myself facing issue with 2014 Duke 390, the speedometer is behaving erratic. When ridden at slow speed gives the speed reading but when accelerated speed becomes 0. It gives on and off speed reading, it has not become permanent 0 as we have seen many cases, what could be the problem? One more problem is the ignition coil contact has got rusted, it was not starting few days back, after inspection I found that there was no spark in spark plug, so I cleaned it and it started fine. How much this coil cost? Last but not the least, the bike has not been used much in last few months, it has been used like 1500 km and mostly stayed unused for few months straight. The oil was changed 6 months back, should I keep using the oil for another 2-3k kms or its wise to change it now. Please suggest. Thanks.

Re: KTM Duke 390 - Ownership Reviews and Experiences

hi there

is did chain better?? I want to fix in my ktm

Re: KTM Duke 390 - Ownership Reviews and Experiences

for the speedo related, it can be either the speed sensor or worse the stator coil. the speed sensor is around 500rs and easy to replace. the svc can check if it is the coil by measuring the resistance across its pins and by also checking the battery with a voltmeter.

no idea about the ignition coil cost. if the rust isn't too bad, clean it and apply a spray of wd40 now and then.

the oil will be safe to use for 8-12 months/5000km depending on usage.. especially if it is the motul 7100. this is from personal experience. make sure it is at the correct level.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Speedo showing 0 post higher speed means we have a faulty battery or a faulty stator coil. The reason the speedo showing erratic reading is the components not fed enough juice, which makes them prone to acting strangely. The most common is the speedo going ZERO which would mean a dead or dying battery or a faulty generator coil. Ignition coils are pretty robust for the most part, you need not get them replaced. Remove them, give them a little TLC with Zorrik or WD 40 and you're all set. Make sure the spark plug is cleaned and the spark plug cap is securely fixed to the ignition coil wire. Spray little WD 40 or Zorrik inside the spark plug cap.

You can extend the oil for another 2k without any issues. If you're planning for a long trip say above 2k I'd suggest you change the oil. If you're basically going to commute, you can extend the life say another 2k with no issues. Make sure you get your coolant level, tire pressure checked.

DID chains are the best, if you can get them, get them eyes closed. But before that check them if it's a genuine stuff and make sure the you get the right pitch.

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

I don't know of they last more than stock ones.

Re: KTM Duke 390 - Ownership Reviews and Experiences


I shall do that when I fix the engine back. Thanks for the tip.





I can't feel any pitting. It's smooth as I run my finger over it. But compared to the edges of the cam lobes where there is no wear, I can feel a very slight depression in the middle. My plan is to recheck the camshafts after about 5000 km.





Got new intake valves from the service center but was disappointed on opening the packet. One valve was defective.
The 2 pics below show the opposite ends of the same valve. One side is ground more than the other. No way this is going inside my engine. I still have to get the exhaust valves.

Defective new intake valve from the service center. Not gonna use it.



So I decided to clean all the valves. Not something that I'd want to do again as my fingers were pretty numb by the end of it. I hooked the valves to a bench drill and used 3M scotch brite pad and Throttle body cleaner to get rid of all the carbon. Took me two hours for 2 intake valves. Took care to not touch the valve stems at all. The intake valves look good ( very very mild pitting - one or two spots) and I'll reuse them. Also, I'll be changing all the valve stem seals.


But what could be the cause for so much carbon? Would fuel additives help? No wonder I've lost power and acceleration. The engine feels rough and the vibrations after 8000 rpm are unbearable.


Old Intake valves with carbon deposit.



Old Intake valves cleaned. Yup, they are the same old valves.



The exhaust valves though are slightly pitted with spots all around. I'll get the new valves tomorrow.
Old Exhaust valves



Old exhaust valves cleaned. The spots on the valve face are actually tiny pits and not just carbon deposit. From what I've read it can cause sealing issues.



Next it was time to clean the valve seats and intake/exhaust ports. I only used waste cloth and throttle body cleaner for this task as I did not want to damage the valve seats. Hence the brown residue still on the surface. It won't go no matter how much I rub. If anyone knows of a better method please let me know.

Valve seats and ports. Before.



Valve seats and ports. After.



And time for the piston head. This was the best I could do with just waste cloth and TB cleaner. Scotch brite or other abrasives would leave marks.


Piston Head just after disassembly



Piston Head after cleaning.



Piston head with rings. Removing the gasket below was a nightmare.



Piston head with rings after cleaning.


Now I'm left with reassembly, but it's a slow process because of lack of parts at the service center.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Raju, an excellent write up and it's a wonderful catch that you can see the grinded area of the valve is a complete mismatch on the new valve stem, this can cause the same problem that you're facing now albeit after a few thousand kms, poor sealing and will cause even more carbon deposits. The reason your exhaust valves pits can be due to lots of reasons, right from excess carbon deposits, improper seating of the valves and or excess lean burn which would mean more heat and thus pitty and or spotting. It also depends on the metallurgy of the valves themselves stainless steel or normal steel, we never know which valve uses which grade steel so that can also be a factor. Usually, stainless steel valves are used on exhausts and normal steel on the intake, but again that's my little insight on the valve pitting.

I'd suggest you replace your exhaust valves as you have pitting right on the valve seat face itself, which is definitely not recommended to get it installed. Though you can get a good seating, you definitely won't get a good sealing, which would mean exhaust or intake blowby which in turn would cause carbon deposits.

Your head cleaning procedure is a good job again. To make it even more better, you can use walnut shells to clean your head and ports, walnut shells are hard yet soft on impact unlike sand which erodes the metal itself if held too long. You can get it done where they polish ports, for that even extra clean head and port.

On your question of reducing carbon deposits, yes periodic using of injector cleaners can go a long way in "reducing" deposits, especially on the back of the valves which is caused by the crankcase breathing system rerouting oil/fuel/vapor mixture back into the intake, it's here where the gunk cooks itself over the valves and adulterated fuel too. Periodically using these cleaners helps keep reduce gumming the intake and helps in better throttle response.

Now that you're giving your engine top end a thorough overhaul, it's recommended that you use additives after a few 1000 kms and also CLEAN YOUR THROTTLE BODY and your fuel injector thoroughly, replace your spark plug before putting everything back on.

Keep your observations coming, raju.

Cheers!
VJ

Re: KTM Duke 390 - Ownership Reviews and Experiences

Just curious, I always knew even the new valves coming from spares will always be imperfect and one needs to lapp both valves and valve seats to make it perfect seal by a skilled person?
To me new valve looks correctable and will even out after lapping with a proper grade and quality lapping compound, and it can even remove any exiting pits to some extent on current valves.

I might be wrong, any corrections are welcome.

Also, can you please post the pics of cylinder walls if you have it by any chance.
Thanks.

Re: KTM Duke 390 - Ownership Reviews and Experiences

hello guys .
I prefer to use engine flush to keep engine healthy.
but I haven't yet used any of flush but heard it keeps engine clean.

my service centre in srinagar is worse than roadside mechanic.

Re: KTM Duke 390 - Ownership Reviews and Experiences

Got the new exhaust valves and they were perfect. Any new valve needs to be lapped onto the valve seat for proper seal. So that's what I did yesterday. Managed to get some coarse lapping compound but the fine compound is just not available. I'll have to order it online. Also, nobody knows about the lapping tool over here and from amazon it'll take 2 to 3 weeks so I used a suction dart from a toy gun as the tool. It worked, surprisingly. The other method is to use a hand drill connected to the valve stem but since the valve seats and valves are in great condition I went for the old school method. I used online videos for reference. I also lapped the 2 old intake valves.


My 'Lapping tool'





Difference between Lapped and Unlapped valve seats.





Lapped old intake valves.The grey bands are continuous and full-circle ensuring complete seal (hopefully). Lapping with fine compound still to be done



Lapped new exhaust valves.





Lapped valve seats.(All four)



The lapped surface is a little rough to the touch and needs to be lapped again with fine compound. This will be done later.




Thanks. Yes, I did not want to take any chances so I've put the old intake valves back in. Also checked with magnet and exhaust valves are stainless steel and they also cost more than intake valves. Intake valves are normal steel like you've mentioned (stuck to magnet). I asked a place where they do sand blasting but they had no clue about walnut blasting. I searched online for walnut blasting in my area and I got top 20 walnut retailers instead.Duh. Another method is vapour honing/blasting. The results are pretty impressive. I think adulterated fuel is a big factor because most of the times I end up filling petrol outside the city. I'll use additives from now on and check the intake valves for carbon deposits through the port every 2000 km.

Here's another view of the intake port. The black stuff is on the valve seat. Same with the other port. This was not hard but gummy like tar and it came off easily.



I'm no expert nor do I have any experience working on engines. This is the first one. So here's what I think after reading about it.

I think it's the seal between the valve and the valve seat that's imperfect and hence lapping is required. The individual valves have to be machined as perfectly as possible.
If you look at the picture below you can see the difference in thickness of the opposite ends. I've measured the thickness using a vernier. The other new valves were perfectly machined so it does look like a manufacturing defect. It may even out by prolonged lapping but wouldn't that also wear out the valve seat? Valve seats need to be as per spec in the service manual. Pitting can be removed with lapping but I've got new exhaust valves and they're good.

Rejected new intake valve.


Here's the cylinder wall pics. You can clearly see the crosshatch pattern on the cylinder walls. There's also some scoring marks but I can't feel them with my fingers. The walls are super smooth. The dots that you see are only visible under direct light and again, can't feel them with my fingertips. Should I change my piston rings also?

Cylinder walls at 16000 km.



Here's the other side.




I'll flush my engine before every oil change from now on. Coupled with fuel additives the engine should be a lot cleaner.

Re: KTM Duke 390 - Ownership Reviews and Experiences

nice diy getting your hands dirty. do a leak test to ensure that they are sealing properly before putting it all back together.
lathe shops that work on engines or car workshop guys can help you with the lapping tool/compound, and maybe take this head to one to get it checked for valve sealing.
what engine oil do you use and how often is it changed?? the deposits and the wear on the cam lobe seem to be on the excessive side

try using "iftex system-g" or "adon-p" additives in the fuel and see if that helps. the former is available at some BP pumps, while the later is sold by IOC. Use it at the ratio of approx 1ml per litre of fuel or a bit more doesn't hurt too.

Re: KTM Duke 390 - Ownership Reviews and Experiences

[MENTION=101036]raju22[/MENTION] gr8 going for DIY.
From the photos it looks that the valve guide seals let in a fair bit of oil which got cooked.
After the assembly do post a review of the performance and refinement difference pre and post DIY.