Ok, my bike is a 1990 KDX 200 I've had for 4 years. It has boyesen reeds, FMF K-14 expansion pipe and a FMF Powercore silencer. I have a trail tech vapor gauge on it too. It has always run great and been super reliable. Until this month I rarely rode it, maybe once a month to keep it going. Then my riding buddy got a KX 250. Now I'm riding the KDX a lot more, and I have developed a coolant system problem. I'm pouring coolant out of the rad cap when i get on it, coolant smells smoky and is cloudy and it bubbles when running. (It starts leaking around 105 F so it's not overheating) So, I'm pretty sure I have a leaking head gasket, or worse. (Cracked head or cylinder) I am going to tear into it this weekend but I want to reach out and ask if anybody has a right radiator and rock guard they are willing to part with? Mine is bent bad. Any info on my problem or advice on top end tear down is welcome, I have a service manual and am mechanically competent but I always appreciate advice. Thanks.
KDX in need
- Thread starter Bafoonage
- Start date
jaguar
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If you suspect a warped head then just use sandpaper on glass to plane it even
- Thread starter
- #4
I tore the KDX down yesterday and I think I have a bad head gasket. I had drops of coolant in the top of the cylinder below where the head bolts on. Everything looks really good inside. Reeds look new, exhaust valves are shiny and free moving and the piston looked pretty clean. I'm going to clean it up and decarbon everything then reassemble with new gaskets. I may put new rings in it if they are past or close to the service limit. Are all the head gaskets rubberized? Mine is and it looks like the rubber has just deteriorated to the point that it is flaking off.
jaguar
~SPONSOR~
Sometimes you can get lucky by using copper coat on a used head gasket
- Thread starter
- #6
Well, I think I'll go ahead and reassemble with a fresh top end and gasket set. I found that my left exhaust valve gear was stripped when I disassembled the head, so I'll be throwing a new one in as well. Is there any special procedure to timing the main KIPS valve? I have a service manual and the timing procedure clearly covers the side valves but doesn't say much on the main valve.
