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Need help guys

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First off I would like to say hi to everyone, as I'am new to the forum. I bought a 02 ktm 125 sx for 200 bucks. Needs a few things but nothing to major. My question is this. I noticed coolant, leaking from the front of the head where it bolts to the very top of the cylinder. I pulled the top of the head off, and seen that the old gasket was torn in 2 places. It looks like a standard head gasket similar to what you would see on a car, buy only with one cylinder. Every where I have been looking, people keep telling me to use the o-ring head gaskets. Can someone enlighten me on which is better, and I know their is 1 big o-ring for the head but what is the small one for that is shown to go in the cylinder before you put the head back on. I know it sounds like alot, but I have always worked on yz's my whole life until I got the honor of owning this master piece of a bike. If someone can shed some light on this for me, I would be great full and maybe a diagram of it. I ordered athena top end gasket kit from ebay, which I got for 12.00 shipped. I hopped I spelt it right, but I did make sure its the real deal and no fake. Any and all help would be greatful, anyone can email me at malcome83@Hotmail.com

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It does have a new top end kit in it, but the guy before me used German torque specs "good-n-tight" or reused the old head gasket. I do know the top end is new, I'm just trying to get it fixed. One more thing, what kind of oil is good for my crank case and clutch. Does red line, or royal purple make any? Just trying to get some ideas. Back to it though, I just wanted to address the coolant leak.

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There are many resources online to see take-apart diagrams. Try this one and see if you can get the information for the head and how it goes together:

http://173.74.246.25/elitektm/catalog/showpart_2007.cfm?componentid=11686&engine_number=081511&chassis_number=%20610120&model=125%20SX&show_engine=1

It should have two o rings, not a gasket on the head :smirk:

The cylinder uses a standard 4 stroke style head gasket as its "base" gasket, squeezed between the bottom end and the cylinder. The Athena kit might not come with those o rings, usually it only comes with base gaskets in different thicknesses. Those two head o rings can be purchased at a local dealer or ordered online from the link above if need be.

I'd also order the little washers that go under the head screws whilst your at it and of course, throw a new piston in there whilst its apart.

In terms of oil in the crank, I use standard motorcycle engine oil designed for wet clutches, 10w30 which is what KTM recommends. Normal gear oil doesn't have the necessary detergents to manage the wet clutch. Sometimes if I get lucky, the near by shop has the Motul 2 stroke tranny fluid, so I will by that from time to time as its exactly what you should use.

Ohh and since you didn't ask 40:1 on the oil/fuel mixture is a good start. :bonk:

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You may want to verify, but i believe the older small bores came with paper gaskets for the head, not o rings. No way to switch without swappin the jug and head out of a newer bike. Replace the gasket and give it a go.

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You may want to verify, but i believe the older small bores came with paper gaskets for the head, not o rings. No way to switch without swappin the jug and head out of a newer bike. Replace the gasket and give it a go.

That link above is the KTM manual for the requested year and it has o rings. Woops... sounds like either its not the bike the OP thought he was getting OR, someone put a paper gasket in there! EEK! :bonk:

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I have looked in a few places, and they are all showing o-ring kits for the head gaskets. The top of the jug does, have the grooves in it for o-rings. The problem is I can't find the paper type gasket, that was on it when I pulled it apart. So I guess I'm gonna try the o-rings, and see how they do. Everyone has been telling me that, they work good in place of the paper gaskets.

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I have looked in a few places, and they are all showing o-ring kits for the head gaskets. The top of the jug does, have the grooves in it for o-rings. The problem is I can't find the paper type gasket, that was on it when I pulled it apart.

Did you read my post just above where I linked you to the actual take-apart for that motor so you can see the o rings?

So I guess I'm gonna try the o-rings, and see how they do. Everyone has been telling me that, they work good in place of the paper gaskets.

Huh? WOW you're really confused somehow.

If the bike is the one you say it is; YOUR MOTOR DOES NOT USE PAPER HEAD GASKETS PERIOD. It never did, it never will, whoever put that paper gasket in there was an idiot. KTM switched to o ring gaskets a long time ago and its been that way ever since. Your motor is designed to use two o rings, per the picture I posted above. :bonk:

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