Quote IDRIDR:
"It allows fluids collected into the spark plug area to drain out."

Which I read as if any fluid collects in the deep hole that the plug sits in - it'll seep out through this hole.

My concern would immediately be: where does it then come from ?
I find it logical to assume it happends when the engine is cold - else the fluid would evaporate before seeping through the hole - agree ?
Would assume that the spark plug hole is in the head, so that there is no divison there and thereby no gaskets that could leak. Bloody impossible to see down to the spark plug without taking the head of ;o)
And if there is no seals in that hole then the fluid has to come from above ??
Just tried too look at the repair manual - can't see any gaskets above the head gasket - at least not where coolant could come out - only oil.
Well - except from the bolt-on fixture for coolant hose right above the weep hole ;o)

It would be very locigal to suspect the fixture's gasket or the attached hose to be leaking.

 

Another possibility? Tiny amounts of oil wets the two gasket areas circled on the original post, which, depending upon the color of the dust in the environment one rides, and the color of the oil in the crankcase, could appear to have a greenish tint.

 

Rain water that didn't melt; the deep puddle crossing; washing the bike. Sure, it should evaporate if the bike was running, but it makes sense to have the weep hole so grimy water doesn't just set there, evaporate, and leave layers and layers of dirt and grime right down there in the plug well. And on another note...isn't this plug well just a prime target for crud building up and waiting to fall into the cylinder when the plug is pulled. I really try to avoid pulling the plug without at a minimum being able to shoot some compressed air down there first. Even better, pull the tank and clean/inspect before pulling the plug.


Agreed, fluid from above or a porous head casting. Someone also mentioned a radiator could leak and squirt into the right direction to dribble some down there.

 

A porious casting is next to impossible to find and is usually the diagnosis after all the gaskets have been replaced and the leak is still the same.

 

I have not heard of a porousity issue yet, but wouldn't a dye and light be able to prove this? Not sure of the type of dyes, but maybe similar to the dyes used in refrigeration?

 

Man you would think with all the washing I do that I would have seen something come out of that, but I never have, oh wait maybe that's because I dry the bike off right away with the leaf blower......whoops was that out loud? LOL

 

 

That must take some finesse to avoid the bike blowing over :d

 

I don't know about dye I guess it would help, I have an old honda 300ex 4 wheeler that leaks oil from the top end and at this point I have replace all the gaskets and such up there and the final diagnosis is a porious casting, if I could find the exact leak the fix is as easy as a smudge of JB weld and it goes away but I can't find the spot.