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Working on my KTM 640, which is the old LC4 motor.
It's been sitting for a little bit and when checking the oil, it was milky. No oil in the radiator. Well, actually, the water level was so low that I couldn't see it but when I did fill the radiator, there was no sign of oil.
Drained the oil from the cases and there was a LOT of water in there. Like a whole lot. Quick cylinder leakdown test and it seems tight so more than likely it's been leaking at the water pump while sitting and not the head gasket. (The cam-driven water pump is kind of a notorious leak point on these motors.)
Two questions:
Question 1-given the passing grade on the cylinder leakdown test, would you assume the problem is the water pump like I do? Or would you pull the head anyway?
Question 2 - How in the hell is the best way to clean out all that sludge in the cases?! If it was a two stroke, it'd be easy. But this thing has two filters and one screen and carries oil the frame. Just suck it up and get a case of cheap oil, some extra filters and run a few 5 minute cycles?
It's been sitting for a little bit and when checking the oil, it was milky. No oil in the radiator. Well, actually, the water level was so low that I couldn't see it but when I did fill the radiator, there was no sign of oil.
Drained the oil from the cases and there was a LOT of water in there. Like a whole lot. Quick cylinder leakdown test and it seems tight so more than likely it's been leaking at the water pump while sitting and not the head gasket. (The cam-driven water pump is kind of a notorious leak point on these motors.)
Two questions:
Question 1-given the passing grade on the cylinder leakdown test, would you assume the problem is the water pump like I do? Or would you pull the head anyway?
Question 2 - How in the hell is the best way to clean out all that sludge in the cases?! If it was a two stroke, it'd be easy. But this thing has two filters and one screen and carries oil the frame. Just suck it up and get a case of cheap oil, some extra filters and run a few 5 minute cycles?
As for cleaning I’m not sure, I’d try cycling oil through the engine.
In the past I have used a small amount of diesel fuel in the engine oil to break down the sludge, but it may damage your clutch plates, so only run it for a few minutes at a time.
Paw Paw
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