KTM 790 Duke Forum banner

CSS: Why does it leak?

  • Poor machining of surfaces surrounding the Seal

    Votes: 2 16.7%
  • Chain too tight creates uneven wear

    Votes: 4 33.3%
  • Engine case machinists, come back from a 5 Martini lunch, and stuff happens

    Votes: 4 33.3%
  • Other: Post up your thoughts.

    Votes: 2 16.7%
1 - 13 of 13 Posts

·
a d m i n .
Joined
·
151,086 Posts
Discussion Starter · #1 ·
I'd like to get a consensus to this mystery, a pole is in order:
 

·
Banned
Joined
·
282 Posts
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.
 

·
a d m i n .
Joined
·
151,086 Posts
Discussion Starter · #3 ·
I‘m hoping more members post their thoughts, as I want to forward this to KTM.
 

·
Registered
Joined
·
37 Posts
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?
 

·
Registered
Joined
·
99 Posts
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.
 

·
Banned
Joined
·
282 Posts
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 🤷‍♂️


5024
5022
 

·
Super Moderator
'20 Street Triple 765
Joined
·
639 Posts
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.
 
1 - 13 of 13 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top