950 ADV puking coolant a sustained triple digits

Just got back from a Baja trip. With a few long pavement days. We were doing sustained triple digits for times of a hour or two plus. The 950 would over fill the coolant reservoir bottle and puke out on my right leg. topped it off a few times, when it cools down it wont drink the fluid back in. The bike never over heated. runs like a top.

New radiator cap?

anyone else seen this?

Try radiator cap first. Make sure the rim where the cap sits is clean. If that does not work, could be that the head bolts are loose. If that's the case, make sure the head bolt TSB has been done.

Don't forget to burp the system when you get the new cap in place.

Yeah sounds like cap. The advice to check the sealing surface is good too.

I'm having this issue as well.. It's either the cap or the head gasket / head bolts.

Try cap first, as others have suggested.

Most like the cap has residue on the seal ring and there wont allow the system to pressurize and that brings the boiling point way down

Sorry to say it but most likely head gasket.

Try this test:
http://advrider.com/forums/showpost.php?p=18487671&postcount=7

/OT

Some 950s have the head gasket problem.
From your description yours is one of them.
Before anything, change the radiator cap and make REALLY REALLY sure the system is well burped, because this might cause almost the same symptons.
But, if it still happends, new head gasket (might as well make sure the cyl and head gasket are perfectly flat since you're in there), new head bolts as well as nuts and washers.
This is a TSB.

His signature says he has an 06 Adventure 950. This bike DOES NOT need the head nut TSB. These bikes were already fixed before being delivered. It can still be a head gasket, but I'd look elsewhere first.

I'm sorry to say, but i have seen 990 that had the early studs (they were early versions) as well as the "defective" oil pressure regulator.

Anyway, like i said, make sure is nothing else before doing anything else.

Is there any consensus out there relative to LC8's that replacing stock radiator cap with an uprated (higher) PSI limit will have positive result on reducing boil over, or negative impact on the cooling system?

Most of the late model KTM thumpers come with 1.8 bar/26psi caps. But it seems all years of KTM bikes 690-1190 are only equipped with 1.4bar/20psi caps.

Thoughts?

I would think that more pressure would result in higher incidents of water pump seal failure.

Pop the cap and look under it. You could eliminate or conclude on wether this is the problem in two minutes.


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Also have you ever flushed the cooling system since new ? If not then I would lean even more towards the cap leaking pressure


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Thanks for all the responses.

Yes the cooling system has been flushed!
The bike has the updated head bolts.
The bike never boiled over or over heated!
Checked radiator cap on the trip seemed fine.
I have a hard time to believe its the head gasket as this only happened when I was doing sustained 100mph plus for at a minimum of a hour at a time. No sign of loss of oil or power.

I will try this bottle trick to rule out the head gasket

Otherwise, just go with the obvious answer. Slow down!

Lol!


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Ah great minds think alike!

Some of my friends are using a 1.8 bar cap on their 950/990s.. and it seems to be ok. Also my KTM dealer recommended this and gave me a 1.8 bar cap - but I haven't tried it yet.

from what model?