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Discussion Starter #1
Hey everyone,

First im new to this forum, so thanks for having me.

Just picked up a 2018 Duke for a dealer with 10K on the clock, full service history and still a years factory warranty left.

I noticed that there was around 200ml of oil in the airbox today when i inspected the air filter.

The engine runs really well, doesn't blow any smoke, etc and feels like there is good compression.

Has anyone else had this issue?

I've checked the top cover breather and i can't for the life of me find the crankcase breather - is there one? And where is it located?

I've done less than 1000km on the bike so seeing this much oil in the airbox is worrying! I think it may need a rebuild already.

Ideas anyone? Piccys attached
 

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a d m i n .
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Hiya! Welcome!
I've not experienced the oil in the airbox, but perhaps others will chime in.
 

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My RC8 used to do that, any oil above the half way mark blew into the air box which drained onto the rear cylinder. Nice design KTM, thanks.

I haven't heard of the 790 doing it though. How full is your oil?
 

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Discussion Starter #4
Hey bigbadmad,

Dealer did the oil change, oil looks like its right in the middle...

Any one else experienced this?

Thanks,
 

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Its bound to be blow back, more than likely its been over filled at some stage. Clean it out, ride for a 1000kms then recheck, its quite common to get oil blow back, especially on twins. Terrible idea to put it into the airbox, but E4.
 

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I have not even looked at the routing for the hose, but couldn't you just remove the hose and let it drain outside and plug the box.....providing you don't aim it at the back wheel!?
 

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a d m i n .
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I have not even looked at the routing for the hose, but couldn't you just remove the hose and let it drain outside and plug the box.....providing you don't aim it at the back wheel!?
Had a problem with my '12 Husky 511 SMR, oil was spraying, (from high revs), all over the top of the engine.

Seemed the answer on the forums was to install a catch can, kind of what you're suggesting.
 

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Had a problem with my '12 Husky 511 SMR, oil was spraying, (from high revs), all over the top of the engine.

Seemed the answer on the forums was to install a catch can, kind of what you're suggesting.
Just seems really odd that they would route an overflow for anything to the air box.
 

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Discussion Starter #11
UPDATE
So after another 1500km or so there is still oil in the airbox, not as much but it's still there.

The oil is also only just showing in the sight glass - so a significant amount has disappeared!

Im off to the dealer tomorrow. I've asked for a full compression test and diagnosis. Still have over 12 months factory warranty so if the rings are gone, im asking for a full rebuild or engine replacement.

Pretty pissed off! Only 12,000km on the clock! Far out!

Can anyone else report significant oil useage? Burning or blow-by?

Cheers,
 

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Discussion Starter #12
I've done almost 1,500km and the engine has guzzled half the oil, no oil showing in the sight glass at all when i check levels.

So dropped the Duke off at the dealer this morning for compression, leak down and oil pressure test. The head mechanic assured me the motor would be rebuilt or replaced to rectify the problem and they gave me a loan bike so fingers crossed it gets sorted asap.
 

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Sounding a little terminal isn't it, using oil and excessive blow by to pump oil into the air box. Good luck, hope they sort it quickly for you.
 

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I've done almost 1,500km and the engine has guzzled half the oil, no oil showing in the sight glass at all when i check levels.

So dropped the Duke off at the dealer this morning for compression, leak down and oil pressure test. The head mechanic assured me the motor would be rebuilt or replaced to rectify the problem and they gave me a loan bike so fingers crossed it gets sorted asap.
Any update?
 

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Discussion Starter #15
So here is the response from the head mechanic at the dealer:

Hi Adam,

Sorry for the delay in replying.

To date we have not received any information from the KTM Au in the relation to the oil issue. I have discussed this with another representative from KTM Au and he is following up with the factory tonight.

The initial checks we have performed on the motorcycle so far have not highlighted any faults, these include visual internal inspection the cylinders and combustion chambers via video scope, compression test, oil pressure test, cylinder leakage test – all results well within specification.

We have also inspected the crankcase ventilation system which shows no signs of any faults.

Both representatives from KTM have told me that this is an isolated case with no other dealer reporting any similar cases.

I will update you as soon as I receive further information. Thank you for understanding.


I have asked for detailed results of the compression test etc. I have also asked for a response regarding how the oil level dropped so low.
We know it was blowing into the airbox.

Anyone got any ideas on what this could be? Surely its the rings?
 

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They've done a compression test so it can't be rings. It's a weird one alright. Do you spend a lot of time with the bike upside down? 🤔
 

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Discussion Starter #18
Hahahaha!

I wish! Im not even that great at wheel stands!

So now dealership is waiting for KTM Australia to approve warranty and cover costs so they can tear down the motor and figure out whats going on.
It's been 8 days. Ill keep updating this thread as progress is made.

Cheers
 

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Discussion Starter #19
Update - KTM AUS have authorised repairs. The dealer has the motor on the bench and is stripping it down for inspection.

Here is the weird part.
1 - YES it is using A LOT of oil.
2 - compression, leak down and oil pressure tests are all well within spec. Also camera inspection shows the bores, etc look fine.
3 - The oil separator is doing its job and working fine.

No one really seems to know what is causing the oil to blow in to the airbox, and there is NO smoke so if it's not getting past the rings, how is it losing that much oil?

Im really keen to know the results of the teardown, and hopefully me documenting this process all the way will help owners on this forum should they ever develop this problem!
 

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a d m i n .
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I'm really keen to know the results of the teardown, and hopefully me documenting this process all the way will help owners on this forum should they ever develop this problem!

How did that all play out, Adam?
 
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