[J D]

I'd like to get a consensus to this mystery, a pole is in order:

 

[weaksy]

A bit of all three?
This is my 3rd new KTM. The other 2 leaked within 500 miles (both 690s). Currently at 4300 miles on the 790 and no leak from the CSS, yet.
I've kept the chain tension as shown in the 2020 manual, as opposed to the method shown in the 2019 manual, FWIW.

Seems like CSS leaks are a KTM "thing" not exclusive to the 790 and 890.

 

[J D]

I‘m hoping more members post their thoughts, as I want to forward this to KTM.

 

[JustAnotherAnon]

A bit of all three?
This is my 3rd new KTM. The other 2 leaked within 500 miles. At 4300 on the 790 and no leak from the CSS, yet.
I've kept the chain tension as shown in the 2020 manual, as opposed to the method shown in the 2019 manual, FWIW.

Seems like CSS leaks are a KTM "thing" not exclusive to the 790 and 890.

What’s the difference?

 

[Motosupial]

The KTM dirt bike guys seem to think its the o ring. The fix is an aftermarket o ring (and or seal)

 

[Tellem'Ed]

A bit of all three?
This is my 3rd new KTM. The other 2 leaked within 500 miles. At 4300 on the 790 and no leak from the CSS, yet.
I've kept the chain tension as shown in the 2020 manual, as opposed to the method shown in the 2019 manual, FWIW.

Seems like CSS leaks are a KTM "thing" not exclusive to the 790 and 890.

What's the difference in the manual instructions between 2020 Duke 790 and 2019 Duke 790 regarding chain tension to which you are referring? I don't see the 2020 manual posted online. Secondly, when you experienced the CSS leak, was it most noticeable after prolonged sitting, like overnight rest or evident immediately after a ride or perhaps, just with engine running at idle.

 

[weaksy]

I just checked online and the 2019 and 2020 manuals are the same. I would have sworn the 2019 just had the same image that’s on the sticker under the seat, and the 2020 manual has the more detailed pic.
guess I “misremembered” ha

Regardless, if you look at the two posted images, supplied by KTM, they show different amounts tension.
One appears to measure from front lip of swingarm to chain, the other measures from the recessed part of the swing arm.
Yet both images show the same 2-5mm spec. Either that, or I’m just old and confused 🤷‍♂️

 

[weaksy]

Manuals here

Manuals

 

[Rick]

The 2018 manual was different, that's for sure.

 

[Tellem'Ed]

Manuals here

Manuals

Thanks for link. So 2019 and 2020 are the same directions. Sorry to taken attention away from original post.

 

[Theron]

Mine was leaking after few thousand miles from brand new, got it fixed by the dealer and no leaks since then, Im at 16700 miles now.

 

[YoungLion]

790 - 1 replacement kit needed - nothing further
890R - 4 replacement kits to date and the most recent one is holding strong at 1800kms on it now.

Reason - who knows - I tried chain tension which didn't have any effect so I'm guessing machining tolerances or some weird engine characteristic that causes it - I give up.

 

[The Mekon]

No leaks on my 790 at 9000km. I have ignored all the handbook advice on chain tension and set it as I normally would for a road bike. Probably a little loose, but seems to work.