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2009 KTM 450 XCW Crankcase vent leak??

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So recently I picked up a 2009 450 xcw with the single cam XC4 ENGINE, I've heard both good and bad things about these engines but decided to go with the purchase anyway as it was one of the cheaper 450 KTM's in my area (Washington state). Bike runs like a top, however I have a disturbing amount of oil seeping out of the lower crankcase fitting (the one right behind the e-start motor). I've heard of these machines having crappy piston rings from the factory that can cause burning oil, is it possible that excessive blow-by from the cylinder is pressurizing the crankcase and shoving out all that oil? Any help would be greatly appreciated... Gonna perform a leakdown test soon so see what's going on but I wanted to know if I was the only one with this issue...

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3 hours ago, RedBlur98 said:

 

 I've heard of these machines having crappy piston rings from the factory that can cause burning oil, is it possible that excessive blow-by from the cylinder is pressurizing the crankcase and shoving out all that oil?

 

Yes that is very possible, and probable if your crank case is getting pressurized.  I had it happen when I cracked a piston crown blew oil all over the place out that hose, Im glad I wasnt vented to airbox, a bigger mess.

 

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So I filled the cylinder with compressed air and thank goodness it seemed to hold pressure (within 10% leakage which is normal). Now the only thing left to address is the vent hoses with holes burned into them due to KTM's crappy house routing design... If those hoses had holes in them would that maybe be the cause of the crankcase being pressurized because of the lack of vacuum supplied from the carb?

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All hoses have holes in the ends ?

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I guess let me re word what i previously said, the vent hoses had been melted so much by the header pipe that there were holes in them.

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Ah I get you ,your saying the crankcase breather is vented to the intake ? So if the hose has a leak it has zero vacuum ?

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The factory KTM breather hoses are always routed to the intake side of the carb. From what I understand this is to 1) provide a vacuum to the crankcase to prevent pressurizing by the piston and 2) allow oil to flow into the carb to be mixed with fuel and burned by the motor in the event of a tip over, rather than just spilling the oil on the ground. My guess is that because of the vacuum leak in the hose, the crankcase is pressurizing air faster than the breather nozzle can release it, and blowing out any oil with it...

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Posted (edited)
15 hours ago, RedBlur98 said:

So I filled the cylinder with compressed air and thank goodness it seemed to hold pressure (within 10% leakage which is normal). Now the only thing left to address is the vent hoses with holes burned into them due to KTM's crappy house routing design... If those hoses had holes in them would that maybe be the cause of the crankcase being pressurized because of the lack of vacuum supplied from the carb?

No it wouldn't, and Ive also been vented to air for years, as a norm.

are you running a high comp piston, or over bore? 

I think that bike has separate tranny and engine oil supplies, which have been known to delete the oil in one side and over fill the other. Maybe that has something to do with your issue.

As far as burnt hoses, if holes are close to vent opening on motor, you might get dirt up in there.

Edited by Spud786

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I don't know what kind of piston is in the bike right now, I don't remember if the previous owner said it had been rebuilt or not... And you would be correct about the two sided oil problem that some of these bikes had. I'm just trying to weed out all the other probable causes before I have to split the cases... Ouch.

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