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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-477.html)

In that order:

New battery (obviously, after 6 years of hibernation)
New spark plug
New Fuel Pump (company assembly, Pricol for Pricol, not just the motor, at the KTM Authorized Service directly)
Bike run 20+ km daily. 6 days a week. No stale fuel.

Cheers, Doc

Well! O2 sensor is very critical during start-up and idle till it gets warm. So that's one possibility. I'd suggest observe for a week, if the same operandi is observed, would strongly recommend to check your O2 along with spark parameters.

Good luck. Keep it posted.

Cheers!
VJ

It's the opposite. O2 sensor does not come into the picture until the bike is warm. It has no role during start or bike coming up to temp.

Could it be an idle stepper motor issue? 02 usually comes into action in the closed loop and afaik the cold start is usually open loop. Correct me if I'm wrong.

The Duke's O2 is HEGO or a heated O2 in layman's terms. There are some sensors on some vehicles that do not take readings, like an open loop system and completely depend on a preset map irrespective of the throttle position. The Duke's O2 sensor does take in O2 values for calculating precise start up and fueling. If you've ever fiddled with O2 sensor bypassing you would know what I am talking about.

O2 sensor has nothing to do with engine coming up to temp. I referred to the sensor itself coming up to temp. O2 sensor simply helps smoothen the peaks and valleys i.e. idle hunting during start-up as mostly it's rich (OL) for a while depending on the ambient temperature. It does play a role, there's no denying it.

Usually a faulty stepper motor too can cause idle hunting issues, but that's for another day.

Had to edit my post to quote yours, apologies. Yes, a faulty stepper motor too can cause idle hunting, but that's more easily perceptible. The vehicle will stutter, stall and have extremely varying and undulating RPMs and would stall the moment you give it gas. On the other hand O2 sensor failure simply means either you run rich with a CEL on or have immediate stalling, hunting, missing etc.

Cheers!
VJ

Thank you so much guys.

I made a video today morning and sent it to my main guy Sachin.

https://youtu.be/uTfxwMFG7oI?si=qd5Eyccp67qdZhrs
Hope you guys can get further clues from it!

Cheers, Doc

Honestly doc, this video just wouldn't be justifiable enough to come to a proper conclusion unless it's been checked, double checked in person. The same crank time can happen on most bikes that's either parked overnight or even after a hot start, the variables are simply aplenty. Well, I'd wait what Sachin has to offer after "properly diagnosing" the bike in person. Till then it's better to keep my opinions muted as it's basically a long end of a tail.

Keep it updated.

Cheers!
VJ

Vijay trust me. As the rider I know. My starter used to be a trigger starter. Press it barely and engine crisply fires to life instantaneously. Zero lag or hesitation. And the jerky fueling on take off (I actually noticed that first, before the long start).

Cheers, Doc

The starting is definitely slow. I had similar hunting idle behavior on my bike but it used to start up quick enough from cold. But it used to sometimes show a hesitation to start if you stopped for a refuel or something. I had to give some throttle in those occasions.

While its well known the first batch of Duke master cylinders were horrible, there have been revisions since then.

From 2016 onwards, 390s came with bybre MCs with MC13 in them. Sometime in '21, it was revised again and you'd get MC16 markings in them. I bought 2 MCs in 2022, both came with MC16 marking.

I just bought another for my 200, turns out there is a new revision called Mc20. I'm not sure what's changed for sure but its welcome. Service center did not have the 390 version with adjustable levers hence bought the 250 version without adjustable lever. Price seems to have gone down, just Rs 1051 with a lever, brake switch and what not.

Part number is 36JP0016. If you were in the fence about getting one, get it and make sure its packed as new as possible to get the newest version.

I'm using this master cylinder on my 2013 D390. I have no experience with the first batch master cylinder, but as per my riding style, this MC deos the job for me.

The 200, 390, now the 250 all use the same master cylinder. The lastest gen, 390 especially comes with an adjustable lever , which eye wateringly pricey -- costs ballpark to the Brembo pads themselves. Right from inception, the pads the rotor, the caliper every aspect of the brakes were and still is made by Bybre.

I wouldn't term the old MC/brakes as horrible, but simply were not progressive enough, coupled with the organic brake pads they came with meant the braking wasn't confident inspiring to say the least -- they were simply okay doing okay speeds. When speed goes up that's when they left wanting more.

I still am using the same old MC from 2015 and I've swapped the OE organic to OE Brembo sintered pads coupled with DOT 5.1 and an adjustable lever. All I can say is, I'm using either my index or middle finger and it can do stoppies if you want to.

The newer front MCs I reckon come with a lengthier pushrod and improved piston, as I'm told the older and newer MC rebuild kits are slightly different owing to the rotor dia difference. The markings inside them makes no difference, just like RX purists would swear by G1, G2 bores and would be willing to lose an eye over which is best.

With all the jingalala aside, personally find zero difference in braking performance between the current gen and mine after the simple swap. YMMV

Cheers!
VJ

Good for you if you don't find any difference. I do, and its massive.

I thought the same, eh all MCs are the same, why bother changing. Then I changed and then realised what a massive difference it made. I guess you're not very particulars about your brakes working perfectly and that's alright. Not everyone likes sharp and tight brakes, most prefer a loose and spongy lever.

Small correction from my side. The MRP may be 1051 but strangely I was only charged Rs 943 on the bill. Money saved is money earned and I'm not complaining.

So this 250 MC is the same as the ones for the 200 as well as the 390, just that the 200 and 250 ones have normal levers, and the 390 ones are the ones that come with adjustable levets, as the ONLY difference?

Asking coz I have decent sized hands and adjustable levers are not a tjing for me. So I'm happy with normal levers, as long as Im not putting a 250 part on my 390, where the basic 390 part (the MC itself) is slightly different.

Do you use the standard service center DOT spec with this new MC or 5.1?

Do you use normal organic brake pads with this new MC or sintered ones?

Thanks for the tip! A thousand bucks is the sweet spot I would be willing to pay for better front brakes.

And NOT as a consumable (pads).

Cheers, Doc

Oh dear! Seems like the important aspect of my post had been skimmed - would recommend to re-read it and digest it. Again, like always, you answer your own questions albeit in a different state of tune when quoted. Not to sound scourge and know-it-all, let me clear my understanding -- this is precisely why Duke's per my understanding the earlier batch brakes were soft and not overtly aggressive.

Quoting your exact answer

Back then with a 4 pot caliper, and most of them switching from drum and two pot calipers, many people simply would have the same "handful" brake syndrome which would eventually lead to a crash or simply plain cost cutting with the added benefit of both.

As things have evolved thus far, the need for better brakes progressively has trickled down to users by manufacturers giving us better quality pads, calipers and what not. Again to reiterate in layman's terms, I'm not demeaning your findings nor will agree to the blank statement of horrible brakes -- the entire statement and the following answer is simply an oxymoron.

This is super-precisely why I wanted to bring your quote again. In one aspect, the sponginess is "horrible" in the other aspect the same "horrible spongy and loose brake lever" is a plus. Again, an oxymoron. I sincerely don't understand the meaning of "particulars" but I shall not try to dissect it any further, which doesn't yield significant insight. There is more to brakes than fancy calipers and rotors. Any T D and H can swap a brake system from any bike and call it the god of brakes -- and I am not to argue. But if he or she knows his/her brakes really well, he/she would sincerely understand what I am trying to convey.

DM me if you have any further queries, would be happy to answer it there, private, purely to keep the thread to its sanctity.

Good luck!

Cheers!
VJ