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2019 350 XCF smoking out of head vent tube

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The KTM clutches generally last twice as long as a Japanese clutch so if you was is wearing early I would look for the root cause

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On 5/21/2020 at 10:56 PM, KTM753 said:

I appreciate your detailed response.  I updated my idler gear with the 6100 part # recently and I verified that it was engaged with the clutch basket. So I am thiy mine was either the breather tube or an oil passage blocked. I have my engine on the bench and I will split the cases and clean all the passages and nozzles out. 

Does that cam breather tube just pull out of the camshaft? Mine didn't want to come out with a little force. I didn't want to pull too hard. 

To remove the cam breather you will have to loosen the cam bridge, and possible the tension off the cam chain. 

The cam is hollow and the breather just sits just in the end of the cam. If the breather melts the plastic finds it way into the cam and comes out a series of holes in the cam shaft, spraying everywhere, the hot plastic liquid then dropping back into the sump, and is  recirculated back through the oil passages  and jets. 

Although a bit of a chicken and egg scenario, I'm not sure what happens first. Oil pump failure, overheating oil / motor, blocked oil passage. 

Keep us posted on the result of the findings. 

6 hours ago, kevvyd said:

I know I have overheated the clutch in my 350 and the smoke came out that breather tube.

Somebody suggested to me that the 350 clutch basket sits kind of high up on the motor, rather than lower down and deeper in the bath of oil where it would be better cooled.

Your bike having blued the steels in the clutch after just 6 hours of what should have been non-clutch intensive (desert) riding is very.....interesting.  I bet if you open the clutch now they will be darkened even further, and likely stink like the smoke that came out your breather.

There is an oil jet that is supposed to squirt the clutch pack during operation.  If this jet was blocked the clutch temps would be increased.  I do not know how to verify that this jet is squirting or not, as it is behind the basket and can't be seen while the engine is cranking.  I'd really like to know how to verify this oil passage/jet function--maybe some engine guru can chime in.

Or maybe you have some other issue that is causing the clutch to slip a little even when it should be fully engaged.  Perhaps a bleed issue in the slave/master or something else hanging up not letting the pressure plate fully clamp down. 

I'll double down on the smoke being clutch smoke.  Which is a lot easier than cam smoke.....

Go ahead and have a look at that clutch pack....lets seem them steels.  Once blued.....now blackened?

 

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1 hour ago, 12main12 said:

To remove the cam breather you will have to loosen the cam bridge, and possible the tension off the cam chain. 

The cam is hollow and the breather just sits just in the end of the cam. If the breather melts the plastic finds it way into the cam and comes out a series of holes in the cam shaft, spraying everywhere, the hot plastic liquid then dropping back into the sump, and is  recirculated back through the oil passages  and jets. 

Although a bit of a chicken and egg scenario, I'm not sure what happens first. Oil pump failure, overheating oil / motor, blocked oil passage. 

Keep us posted on the result of the findings. 

 

Other than lower oil temps, how else can this be prevented? 

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7 hours ago, shrubitup said:

Other than lower oil temps, how else can this be prevented? 

I'm no expert, only going on what I've experienced. Mine was a warped oil pump idle gear, it was the older part number, it caused oil starvation to the head. 

I'm not aware of any aftermarket mods for the 350 that would directly lower oil temps. Increasing the rad cap pressure and installing an oversized waterpump  would go some way to reducing engine oil temperature by indirect means. Keeping a tight filter and oil replacement schedule would help prevent any debris clogging the oil supply lines,  checking the valve oil jets and cam breather at regular intervals to hopefully discover any issues before they arise. 

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The 350.has proven to be very reliable ,some have failed but you have the new gears , you can over think a problem 

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1 hour ago, 12main12 said:

I'm no expert, only going on what I've experienced. Mine was a warped oil pump idle gear, it was the older part number, it caused oil starvation to the head. 

I'm not aware of any aftermarket mods for the 350 that would directly lower oil temps. Increasing the rad cap pressure and installing an oversized waterpump  would go some way to reducing engine oil temperature by indirect means. Keeping a tight filter and oil replacement schedule would help prevent any debris clogging the oil supply lines,  checking the valve oil jets and cam breather at regular intervals to hopefully discover any issues before they arise. 

Yes, lucky for me it has a aftermarket radiator fan which should overall regulate engine temps.

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