Bad head gasket on my 89 KDX200? Not sure.

[Canon]

I know the scenario that I am about to describe could have many
contributers.....but I am hoping head gasket.

I have an 89 KDX200 that is fouling plugs more often than I care
to admit. Though I have yet to fool around with the changing the
carb jetting, I think I may have noticed something that could be
the culprit.

Just yesterday I removed the radiator cap after making a couple of
warm up laps around the back yard, just to check the coolant level.
I noticed that the coolant looked very bubbly, almost foamy. If I were to let the bike sit for a few minutes, it will all settle back down and look like your run of the mill coolant again. I see no contaminants, oil etc. I don't seem to notice any significant coolant loss after a ride though, so that leads me to believe that if I am blowing it out the pipe, it is very little. Not seeing an over abundance of white smoke, though some is there. Smells like Bel-Ray to me. The plug also never seems to foul out, or bog me down while actually riding. It seems to happen when I have stopped to take a break, sat for a few, and go to crank her up again.
As mentioned, the bubbles have me thinking gasket. Also....will
have to admit, after changing out my KIPS valve at the beginning
of the season, I reused the head gasket.....thinking it looked to be
in excellent condition. Ok....thrash me!! :worship:

 

[IrishEKU]

Turn the fuel off when you stop. That will stop your fouling after short stops. If there is no oil in the coolant and vise-versa it's not a head gasket, my guess is traped air in the system.

Good Luck,
Phillip

 

[Canon]

Will try turning the fuel off at every break and see if this helps. As far as the bubbles go.....not too sure on the trapped air theory. A fellow rider has a 91 KDX200, and we compared coolant after the same amount of run time.....his was total fluid, no foamy bubbles. Road the bike for about an hour that day. Started her up again today, and after short warm up, still had the foaming action. As stated, when left to sit, coolant settles down to normal, with no apparent contaminants. We'll see I guess.

 

[Canadian Dave]

I have an 89 KDX200 that is fouling plugs more often than I care to admit. Though I have yet to fool around with the changing the
carb jetting, I think I may have noticed something that could be
the culprit.

Leaking coolant into cylinder would cause the engine to run lean rather than rich. Your chronic plug fouling problem is the result of something else.

If you are seeing some white smoke at the tail pipe and your coolant is frothing I'd certainly change out the head gasket especially given that you've reused the old one.

It seems to happen when I have stopped to take a break,

It sounds quite possible that your float valve is either allowing fuel to leak past and needs to be replaced or your float level is set too high. Check out the JustKDX web page for directions on inspecting the valve and setting the float level.

David

 

[Canon]

Thank you both IrishEKU and Canadian Dave for some very helpful comments.