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Motor Problems

bsmith

Wise master of the mistic
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#1
01' EXC520
Well I'm some what technically challanged, but think I may have blown a head gasket :( At least thats what I hope happened.

My bike started getting hot, I shut it down and heard the water boiling pretty bad, yet it only lasted for a couple minutes. I pulled the cap off to see if I was low on water, I couldn't see any, so I poured some bottled water in, everything seemed normal
I did however checked the oil, for I just added some antifreeze that morning, and their didn't appear to be any leak! The oil did have some water mixed with it!
I was out in some dunes, not far from another staging area, so I limped it over a couple dunes and up to a parking lot. When I got there I popped the cap off again, and could see a milk shake of oil and water.

So any of you KTM mechanics have an idea of what it could be. I'm hoping nothings cracked!!!You think it could be a gasket or something more?
It was 35 degrees out so at least I had some cold air to help cool it down.

Also, there is no sign of anything near the weep hole.
 
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#2
I had a water pump seal go on a bike which resulted in the conditions you describe (two stroke). No big deal. Tranny fluid was milky white.
 

Hman

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Apr 11, 2000
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#3
Water and Oil exchanges on a two stroke cannot occur across the head gasket. The water jacket on the head and cylinder does not run adjacent to the gearbox oil.

The only place this occurs is at the seal behind the water impeller- so that's where you will need to go. By the way, while you're changing the seal, you may want to change the bearing as well. This is often the culprit of the seal failure.

Good Luck.

H
 

bsmith

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#4
Thanks Guys, It is however a 4 stroke.

But thanks to the wisdom of my wife, I'm just going to take it in and have them take care of it.
 

bsmith

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#5
It appears the bolt that holds the auto decompression shaft on to the cam, broke. Then it got rammed through the head at the bottom of the oil reservoir where it went through into the Coolant system.
This is what caused the fluid exchange. So I need to have the Head welded and throw it back together.
 

mrmodine

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#6
As I'm reading your post...I got concerned.

Unfortunately, this is a known problem for the 01 and 02 KTM 4strokes. The bolt has caused a lot of problems in the last couple of years.

About halfway through 02, they upgraded to an aircraft style (nylock) fastener which helps quite a bit. In 03, they took it even further and integrated the whole thing so there is not nut at all.

If you guys have KTM 4 strokes from 01 or 02, it is a good idea to check on this at your next maintenance interval. Replacing it really isn't too hard but you need to be able to cut the cam chain and then rivot in a new link later. Motion Pro sells a good tool for it and so does KTM. (The MP tool has more uses so a better deal IMO)

Also, if the water pump seals were to be leaking, you would have seen some dripping down the engine on the left side...from under the water pump cover. There is a weep hole there to let you know if one of the seals is leaking.

Christopher