[Rider2022]

As some may or may not know oil has a viscosity rating signified by the “x”W “x” value… or for an example 15W 50 to make it clear.

The manual says to use 15w50.

I am based in the UK (Wales) and usually use 10W40 in my bikes for the typical temperatures seen here.

What grade oil are people using in their 390’s ? Also what country are you in to give an idea of the climate you ride in.

 

[DukeofSeven]

I stick with the 15w50 the engine was developed with. And I do that even tho the warranty ran out in July of 2021.
I did however change over to the full synthetic version after 3,000 miles on the odometer; previously I used the synthetic blend recommended by the book.

As far as my country/climate, I live in the US, on the SW coastline of FL. The morning drive is currently at approx. 60F;
the evening return drive is around 82-86F; the humidity varies between 92-98 % in the AM and 55-67% in the PM.

 

[KTMasean]

Partially true, a multi grade oil will state the viscosity when 'cold' followed by a W viscosity when the oil is 'warm/hot'.
The earlier oils, single grade give only one viscosity index number.
This is for engine oils and is standardised unlike fork oils that bear no connection between brands.
Stick to the KTM manual recommendations is best.

As some may or may not know oil has a viscosity rating signified by the “x”W “x” value… or for an example 15W 50 to make it clear.

The manual says to use 15w50.

I am based in the UK (Wales) and usually use 10W40 in my bikes for the typical temperatures seen here.

What grade oil are people using in their 390’s ? Also what country are you in to give an idea of the climate you ride in.

 

[atinc]

axb grade. a represents the oil thickness when the engine is cold and b represents when its at operating temp.
duke 390 uses 15w50.if you happen to use 10w40 the engine will wear out eventually due to thick oil becase w50 is thinner than w40 when it gets hot.
other than that if you are riding at very low temp,which is below 5 celcius maybe.you might use 10w50.since noone is that crazy.15w50 all day long
btw castrol,motul,motorex or liqu moly would be a good choice.
motul 7100 15w50 is what i use.
interval is at 7500kms but i always change at 4500 kms just in case

 

[atinc]

For further explanation,i must say w50 is thicker than w40,but when the engine is hot w50 is thinner and does the most effective lubricating

 

[Rider2022]

Based on the info seen and comments, I have some 15w50 motul 7100 oil in post… I can use the 10w40 in my fire blade anyway.

 

[atinc]

Btw capacity is 1.7 litres.put 1.7 then wait a bit.start the engine let the oil flow.then stop the engine.wait like 1-2 minutes.check the glass,if its between 2 marks that will be okey.if its close to min mark add a bit .good luck

 

[shush319]

I put Motul 5100 10w40 in my 2016 Duke when I got it with 2600 miles on it. Had the top end off at 6000 miles due to a blown head gasket (manufacturer defect on the head, not oil related). Everything still looked NEW when I inspected it while it was apart. The bore even still showed hash marks like a newer motor. Given that I rev way past the stock rev limit often & the motor still looked that good, I am going to stay with the Motul 10w40, also run the same oil in my 2007 R6 race bike & it has around 26000 miles on it with no oil related failures either..

 

[Mirius]

10w40 is a very common grade for the UK. 15w50 would be more common in hotter climates.

 

[CDN Duke]

I stick with 50 weight knowing how hot these run.

I've been using Amsoil 'Dirt' 10W50 for years.

15W50 is ostensibly better with the narrower spread between the cold and hot. 'They' say it's better when oil has tighter spec.

 

[atinc]

Mirius its not about the climate.its about duke 390 being run hot.thus needs thin oil.w50 gets thin at high temp.otherwise ktm would have said put w40.

 

[DukeofSeven]

I wonder what Tuva, over at Alien New Desk, thinks...

She takes oil, right? 👀

 

[KTMasean]

When also changing the oil filter (as you should) fill 1.7 litre and do NOT top up or add more.

Btw capacity is 1.7 litres.put 1.7 then wait a bit.start the engine let the oil flow.then stop the engine.wait like 1-2 minutes.check the glass,if its between 2 marks that will be okey.if its close to min mark add a bit .good luck

 

[Mirius]

Mirius its not about the climate.its about duke 390 being run hot.thus needs thin oil.w50 gets thin at high temp.otherwise ktm would have said put w40.

The KTM does not run as hot in the UK as it does in the Tropics so doesn’t need as thick an oil.

 

[DukeofSeven]

Wow, i see whutcha mean...
[this just in]

gonna be slippery too, dude.

 

[duke of Ca]

Wow, i see whutcha mean...
[this just in]
View attachment 56036
gonna be slippery too, dude.

LOL- doesnt look any different than in california this time of the year. Biggest difference is in the UK they know how to drive in the rain, cant say the same for California; which leads me to the 50 weight oil debate. I use, as Miruis initially stated, the KTM manual for reference, and I dont mean Motorex(suggested) oil either. I use the motorcycle standardized rating JASO MA to buy my oil. It happens to be diesel oil with a 15w-50 rating. Could someone get by with 10w-40 oil, sure! The difference as mentioned is climate in summer and winter. But a standard aircraft oil is 20w-50 weight and I assure you the temperatures at 17K is well, much colder than most of us want to tolerate on our bikes, so climate isnt so much a factor with what oil one choses as is the effect it has on the engine temperatures. I believe we are in agreement that unless your in the tropics and the heat is in the +40C range the lower number isn't nearly as important as the higher number which in the case of the 50W oil that can go to +50C.
Ive used both weight oil in my location and the 390 oil temperatures have been basically the same.
My takeaway- assure you use JASO MA rated oil, and if in doubt use the higher rated oil if the temperatures are excessive, especially if in stop and slow traffic.
Probably said nothing more than already said 😆

 

[Rider2022]

Wow, i see whutcha mean...
[this just in]
View attachment 56036
gonna be slippery too, dude.

Tuesday in the area I live, given out as -6degrees C …. And this is March, spring … supposed to be even colder in other areas of uk, with 20cm of snow forecast in places.

 

[KTMasean]

I go along with these remarks yet have these remarks.

• I didn't know oil for Diesel engines also had a JASO grading.
• The oil numbers are not weight but it is a viscosity rating.
• as a remark on post #11 these/our engines do not run any hotter than other engines we may experience it as such because due to the nacked bike nature and the header running this close by our left leg, it may seem that way. A temperature gauge on my 200cc (the gauge for my 390 is here in June) reads 75C coolant temperature at an ambient temperature of 30+C

On a side note, I have ridden on a none multi-grade racing oil (Voltronic XM) for over 14,000 km without any noticeable difference. Engine coolant temps were the same.

LOL- doesnt look any different than in california this time of the year. Biggest difference is in the UK they know how to drive in the rain, cant say the same for California; which leads me to the 50 weight oil debate. I use, as Miruis initially stated, the KTM manual for reference, and I dont mean Motorex(suggested) oil either. I use the motorcycle standardized rating JASO MA to buy my oil. It happens to be diesel oil with a 15w-50 rating. Could someone get by with 10w-40 oil, sure! The difference as mentioned is climate in summer and winter. But a standard aircraft oil is 20w-50 weight and I assure you the temperatures at 17K is well, much colder than most of us want to tolerate on our bikes, so climate isnt so much a factor with what oil one choses as is the effect it has on the engine temperatures. I believe we are in agreement that unless your in the tropics and the heat is in the +40C range the lower number isn't nearly as important as the higher number which in the case of the 50W oil that can go to +50C.
Ive used both weight oil in my location and the 390 oil temperatures have been basically the same.
My takeaway- assure you use JASO MA rated oil, and if in doubt use the higher rated oil if the temperatures are excessive, especially if in stop and slow traffic.
Probably said nothing more than already said 😆

 

[DukeofSeven]

And as an aside... I thought one of the main takeaways of using synthetic engine oils was its ability to establish and maintain consistent flow even at sub-zero temperatures.

Plus it is non-hygroscopic.

Plus it does not thicken or thin, or readily evaporate, owing to its inherent chemical stability when compared to refined oils.

[and the list goes on]

I wonder why the engine oil manufacturers don't instead rate their products by cP. Then I'm sure we'd all really have something to go hmm about.

Plus, i'm pretty sure KTM asked for the MA2 friction spec for our clutch discs. yeah, i just checked the bottle again, MA2.

 

[pellicle]

Partially true, a multi grade oil will state the viscosity when 'cold' followed by a W viscosity when the oil is 'warm/hot'.

I always thought the W was for winter, apparently so does Castrol:

The viscosity of an oil is measured by its resistance to flow. There are two numbers that define viscosity meaning. The first number precedes the letter 'W' which stands for Winter. This measurement is related to how an oil flows when it is cold, such as at engine start-up. The second number is defined by how an oil flows at normal engine operating temperatures.​

​

The smaller the number, the better it will flow. A 5W-30 will flow easier than a 10W-30 at start-up temperatures and a 10W-30 will flow more easily than a 10W-40 at normal engine operating temperatures. Engine oil viscosity is important. Engine oils naturally thicken as they cool and thin as they are heated.​

not sure if that's what you meant as I could read that two ways