It's been a while since I updated anything about my 390 in this thread because it was mostly uneventful.
The chain slider of the bike had disintegrated for some time now. Ordered it online from mysparemarket. Rs.350 including shipping.
Installed it from a local shop.
There is still a knocking sound from the rear when the bike is ridden over bad roads. Need to check swingarm bushes.
Well, I was feeling unnatural since life with this bike has been uneventful and reliable. And in true KTM fashion, I realized that the knocking kind of sound was coming from the rear mono-shock.
With 23000 KM and 6 years of usage, the monoshock is shot. My 11-year FZS still has the original mono shock it came with,
Maybe it is a one-off case?
I don't think so. Here is another Duke 390 surprisingly from the same year and has run the same 23000 KM reporting the same issue. Another one from YouTube which looks like the same year bike.
So, this is not a one-off issue and definitely a cause of the low quality of the manufacturing process and poor quality check.
Events like these make me never want to buy a non Jap bike ever else in my life again. Lesson learned in life - If you need a vehicle that needs your attention every time and shows a tantrum every now and then, buy a non Jap vehicle.
If you need something that's dependable and runs like a clock with basic routine maintenance, just buy a Jap vehicle.
Our 21-year-old Alto and 11-year-old Yamaha FZS are enough for me to come in to this conclusion.
New shock costs Rs.5350 from mysparemarket.
If it's possible I wish to install the adjustable Adv. 390 shock or even the 2024 Duke 390 shock. So, for the time being, I am thinking of rebuilding the existing shock absorber.
A friend had rebuilt his Duke 250 mono-shock from a shop here and it's good.
The Shell Advance Ultra has been going well with the bike.
Oil consumption is still there, but not as much as the Motul 7100. Done around 1000 km from the previous oil change. I has to use the remaining 300ml to top up. The oil level after top up is slightly above the max mark. So, I guess the actual drop was something like 250ml.
There are no leaks or white smoke from the exhaust.
Previously with 7100, I had to top up 200ml in 600km.
Something else that I noticed with th Shell Advance Ultra is that the oil has darkened considerably. I mean, it's pitch dark when seen through the glass window.
I have previously only used 7100 and 300v. None of these oils used to blacken as much as the Shell did even after 4000 km.
Is it cleaning the engine carbon deposits which the Motul didn't clean? Or is it just degrading quicker?
There is no reason for any sludge deposit in this engine because I have never run without an oil change over 3000 km.
Since the oil consumption issue is not resolved, I'm thinking about using a thicker oil. This is a classic solution which works. XW60 oils have been used by a few abroad and reported positive results. But this grade is not available in India. The best bet I have is 20W50, which is the recommended oil grade for Duke 200.
But, this makes me think. Why did KTM specifically recommended 15W50 for the 250 and 390 while they were already using 20W50 for the 200. Wouldn't it have been easier for them to have just one oil grade for all the bikes?
From my past experiences with using slight deviations from the recommended oil grade, I have not noticed any issues.
This also makes me remind of what happened with Maruti Suzuki. They used to recommend 5W30 for K12 engines. Later they changed it to 0W20 and then to 0W16. But the ASC fills 5W30 most of the time. And with these ASC, it's not like we can confirm they filled what they billed us for or not.
Oil consumption is normal is newer engines today.
BMW for example, has said that some of their engines can consume up to 1 quart of oil for every 750-1000 miles driven and that it’s normal.
That's 1L per 1200km is normal!
The Duke 390 engine is a highly stressed unit and with a compression ratio of 12.8:1, it runs so hot. I guess the oil would get sucked past the cylinder walls and rings when ridden hard.