Why does my ktm sx85 2014 keep blowing head gaskets??? Blown the head gasket at fatcats other weekend, had a top end rebuild and head ported checked waterpump etc.. carb cleaned and checked run lovely last weekend for 3 sessions. Went to kierdan this weekend 1 session in head gasket blew again. WHY !! Please help

a knocking noise is usually associated with a spun/burnt bearing ---rod knock which would require lower end rebuild or if cylinder walls are also damaged require new block

Do fans come on , if not it is the $8 dollar temp sensor or the fan fuse or the fan motor.
If you have heat from the heater and if radiator gets hot then it is neither the raditor or the water pump nor the thermostat as neither heater or radiator would get hot
because no water would be moving in the system.
So

I suspect that the head gasket is not under the proper tension
IT is very common for people to refit heads without first cleaning out the head stud holes ( thread tap and compressed air)
there is normally water or oil in the hole and as the stud is screwed it it compresses the water/oil and reaches tension by bottoming out on the obstruction but the gasket is not tight

You need to strip the engine down and check the top of the block (deck) for cracks and have it resurfaced, Do the same for the cylinder heads, check them for vcracks and have them resurfaced. Use felpro gaskets.

dry cam.?
so what did you do , just before it went dry. ( nothing. ?)
got full oil pressure, mine does 50 psi cold at sender port on left side.
was head off? yes.?
then you put the head gasket backwards and blocked the 50thou head port. in left front of block deck.
my new felpro gasket is marked, UP. buy Felpro gaskets. then win.
i do top end oil ,last after i rebuild engines, and do it, only with starter
and no fuel. i never burn up engines, new.
not one. yet.

if this just happened by magic? doing nothing?
then the orifice is plugged in the head, mine is 0.050" in diameter.
can clog easy, if not careful.
one way is using RTV and it gets to there.

Oh no! I'm sorry to tell you this but it's serious. That white smoke is actually smoke and steam. Check your radiator for oil. White smoke is indicative of a blown head gasket. If you are mechanically inclined you can try to repair it yourself, but it's a huge job. As a matter of fact, some cars, if you can't repair yourself, some people have to junk it. What is required to fix this is an entire breakdown of the top side of the engine. Throttle body, intake manifold, exhaust manifold, spark plugs, emissions, valve covers, overhead cam<-I believe it's overhead, if not, rocker arms, pushrods and lifters. Remove the head, take it to a machinist and have it steamed and milled. Buy top end rebuild kit. If you are going to replace this head gasket, you may as well rebuild the top end. You actually could try a salvage yard and buy an entire engine and have it delivered to your garage of choice and pay to have it put in. Sorry for the bad news. If you continue to drive it temporarily, just remember that you are losing oil into the radiator and coolant out the exhaust pipe. Check and fill it daily as necessary.

you have a bad head gasket or a cracked head better off to replace engine with a lower mileage motor its better to do and maybe cheaper.the reason i say this is because when you rebuild the top end the lower end becomes the next victim when put up against a newly rebuilt top end.

I would think the head gasket is blown.

The conventional wisdom is that this is a possibility with high mileage engines. But the option of just rebuilding the head versus the entire engine would make the choice easy for me -- I'd rebuild the head... I would say the probability that a new head would damage the engine is kinda low.

there are many was a head gasket can blow . sometimes they just leak to the outside sometimes they leak to the coolant and then it blows out your antifreeze. if you have a blown head gasket you will see it when you pull the head. and yes you should hace the head checked at a machine shop and install with a new head set never reuse a gasket .
later paul