Air Box Problem

[Bill Wu]

Hello everyone,

Did anyone get a problem about your air box? I just bought the KTM RC390 for 3 months and rode for about 3000 KM. But I got a problem of the air box. My air box was broken.


Was anyone's air box broken like that?

And I've asked the KTM owners in Taiwan, they said they did change the air box, but after little time, it'll be broken again. So I have to keep changing it?

Did anyone encounter this problem?

 

[Ryanthegreat1]

Is that from the bottom looking up?

 

[Bill Wu]

No, I took the photo from the right side (horizontal).

 

[Fasteddy]

Mine has exact same issue, I think others have also had this issue. My dealer will look into to a warranty claim next time I am in but I have the same concern about the replacement having same issue so I have been considering just RTV / epoxy repair and being done with it...

 

[Bill Wu]

Yes, repair by RTV / epoxy may be a better choice than keep changing the air box.Fasteddy, may I ask you where was your air box broken? Was it the same as mine?

 

[Ryanthegreat1]

Fancy, I just happened to be out working on mine checking for the cam shaft wear issue. And look my air box is cracked too. Yippy.

One of them Japanese bikes is looking better and better. Uggg.


My welding experience is telling me that crack is forming right along the edge of the HAZ. Someone got their temperatures wrong in the manufacturing process when they melted and fused the two parts together.

 

[Fasteddy]

Yes, identical to your picture. I could put a thin feeler gage toward the rear and applying a bit of pressure causes it to open a bit. I have a few more months before riding season starts so not too worried yet. My thought would be to use RTV as it is more flexible.

 

[Bill Wu]

Thank you both for replying. It seems the air box is easy to be broken on the fusing place...

And I just went to see the forum in China, too. They said the fusing place between the air box and intake pipe will be broken as well. Maybe you guys should have a look there. It's hard to see if you don't look carefully.

Is that possible the engine problem is caused by the broken air box? Because the broken place is behind the air filter, the engine will intake non-filtered air and causing engine problem.

 

[Ryanthegreat1]

Typically dirt ingestion will present as intake valves receding into the head and tightening the valve clearances. Also scoring of the cylinder walls and piston skirt and rapid ring wear.

Doubt it would relate to the cam shaft lobe wear.

 

[KwicK To Master KTM]

Well there you go - Just checked mine also and the exact same crack in the air box as the previously posted photos. I think there is another thread on here with owners having this same issue-


I really thought I had finally sorted all the problems with my RC (idle / stalling etc...) but now this Argggggg. I suggest all RC owners have a good look on their bike as there is a high chance Yours is cracked too.


I really think I is time KTM pay for their cheap shit supply on bikes we have all paid good money for - Once again KTM poor production .

I also suggest anyone with this problem to see their KTM dealer and go for a warranty claim and have it replaced - If you start to mess ( repair it yourself) and it sucks some RTV in through your intakes you will have no comeback -

And also if they supply another one that is cracked or fails then back to the dealer and another warranty claim - Bugger KTM you cannot supply this crap and get away with it time to loose some profit - If enough people do a warranty claim and they still fail then a new method for manufacturing will have to be done by KTM for this item until we all have a satisfied result - This is a world wide issue with this item as my bike was purchased in Australia - and obviously - England and America and India all with the same issue - SHAME AGAIN ON YOU KTM - TIME TO FIX PROBLEMS

 

[KwicK To Master KTM]

Does anyone on the Forum have access to the KTM part number or Numbers for the item / items that would need to be replaced? Thanks

 

[Bill Wu]

Yes, thank you for your suggestion. There are lots of owners in Taiwan (Asia) have this air box issue, too. And one of my friend said he changed the air box of duke 390 for twice. It seems this problem still can not be solved now.

I think you could find the part number from here: KTM RC390 Parts List and Diagram - KTM Duke 390 Forum

I think the part number should be 90806001033

 

[Bagwell]

if the problem is truly unsolvable by KTM at this time maybe TYGA will offer a solution.

 

[cjwell]

Lets clear a few things up. That broken/separation line is the crankcase breather vent separator. It is EXTERNAL to the air box. It is plastic welded/glued on to the air box. It has no baring on the ''filtered" air side of air box. There is only a 3/16'' hole between the breather/separator into the air box to vent. With the amount of oily residue/mist in there from the engine any debris/dust would stick/cling to that, NOT enter the the engine from intake track. I have had several of these apart and now they look/work. "I" don't believe it is anything to worked up about or loose sleep over. Is the best quality? No. It's a 5.5k dollar bike... I can assure you it hasn't caused any engine related "failures" or running conditions. If anything it might drip a little oil out of there, that's all. End of story.

 

[A1VW2NV]

Is the airbox even necessary? ( for us dry weather riders) I haven't dug far enough in yet to investigate.

 

[Ryanthegreat1]

I would say it is required. It has a tuned length port in in and it acts as a resonance chamber/plenum. A pod filter on the throttle body will probably kill all the low and mid range.

 

[Treachery]

Thanks, Chad. I hadn't considered the actual "architecture" of the box, and what might be affected by the crack. Good to know.

My data point is to report no crack to date, but I'll watch.

 

[KwicK To Master KTM]

Lets clear a few things up. That broken/separation line is the crankcase breather vent separator. It is EXTERNAL to the air box. It is plastic welded/glued on to the air box. It has no baring on the ''filtered" air side of air box. There is only a 3/16'' hole between the breather/separator into the air box to vent. With the amount of oily residue/mist in there from the engine any debris/dust would stick/cling to that, NOT enter the the engine from intake track. I have had several of these apart and now they look/work. "I" don't believe it is anything to worked up about or loose sleep over. Is the best quality? No. It's a 5.5k dollar bike... I can assure you it hasn't caused any engine related "failures" or running conditions. If anything it might drip a little oil out of there, that's all. End of story.

Thanks for that - obviously my comments were made from lack of knowledge to the design of the air box (opps) - Do you suggest leaving it? or pulling it apart and attempting a repair? Awesome I will stop worrying and be able to sleep tonight

 

[EnCee]

It is very difficult to see from this picture so I could be wrong here, but is this a definite crack or the top half of the airbox coming unglued?

The model here in Australia maybe different from others but this top half containing the snorkel can be forced off making a plastic airbox mod similar to the MNNTHBX.

 

[KwicK To Master KTM]

It is very difficult to see from this picture so I could be wrong here, but is this a definite crack or the top half of the airbox coming unglued?

The model here in Australia maybe different from others but this top half containing the snorkel can be forced off making a plastic airbox mod similar to the MNNTHBX.

I don't think you are looking in the correct area as this crack is not at the top of the airbox but at the right hand side of your bike just behind the throttle body at the front of your air box - (my bike is Australia so yours will be the same)- this is not at the snorkel end .