Possible stupid question

[B_DRZ]

There is a hole on the right side of my cyl head(small machined hole, not one I put there) *** is it there for, I looked in the manual and cant find anything for it, my old bike was a dr-z 400 and it had one too, if I washed it and water got in to it the bike wont run and water would boil out of it when I got it to run, my yz doesnt do that, but still wonder whats is it for?

[sacfelix]

When you go to remove the spark plug you dont want anything falling in the cylinder. You use compressed air to blow out the crap before you remove the spark plug.

[shoogshoog]

I have a ktm 525sx that has the same whole. Mine is on the right side. I've been wondering what it was for. Maybe some kind of sensor?

[motomanmike26]

When you go to remove the spark plug you dont want anything falling in the cylinder. You use compressed air to blow out the crap before you remove the spark plug.

Exactly....

Its pretty much a drain to blow out stuff so it doesn't drop into your engine.

[grayracer513]

In the event of a leaking cam cover gasket, or smooge leaking past the plug, the hole is there to drain off the fluids.

[B_DRZ]

Makes sence, but why did my drz not like to run if water got in there, did I have a bad spark plug wire? If I plugged the hole with a small plastic push pin, it did not do the same thing, this is the only thing that could possibly have been the issue.

[DrThumper]

Makes sence, but why did my drz not like to run if water got in there,

Probably the spark plug wire grounding out due to the spark plug cable end not sealing well over the plug.

[B_DRZ]

Probably the spark plug wire grounding out due to the spark plug cable end not sealing well over the plug.

I cant belive I never thought of that, but I was only an apprentice at that time.? and I didnt know what the hole was for.