Engine block discoloration

[Lumpy Rider]

At the risk of wearing out my welcome here, I have another issue I would appreciate feedback on. My 2001 had 29k on it when it came to be mine 2 years ago and now has 34k. There is a light brown discoloration of the engine block on the left side that starts right where the head joins the block. It runs downward from there a couple inches and runs the width of the block to the block's rounded corners where it stops. The discoloration has increased in size 3 fold since my purchase of the bike. Upon close examination under a loop I can see no leakage from the head gasket. So...what do you think? Is this a failing head gasket? Overheating issue? Rich or lean condition on #1? Rust? Normal? I have found no evidence of water in the oil and vice versa, nor am I losing any fluid. Sorry to be a bother. Since getting healthy again it's like my brain has come alive and I am tending to many things I did not see before. Can email photo. Tried to post here but cannot get photobucket to run on my Apple computer.

[ekap1200]

Each spark plug ( well ) has a drain passage to the rear, at the union of block/head. Crap will collect there if not cleared out in a timely fashion. Eventually it will clog up and the spark plug will loose its plating and begin to rust. All four of these must be cleared out when changing spark plugs as whatever is in the well , WILL fall into the jug.
If you do see anti-freeze there, it is usually a loose hose clamp or rotting o-ring on the tube-flange and not a head gasket.
Do not remove the spark plugs until all the wells are 100% cleared out, or you will do more damage than good.
And on that note- same ( keep it clean rule ) applies to changing out your air filter. Crap will collect around the perimeter of the filter, and care must be taken to change it. Don't let dirt down into the air box when removing it and if it does , take a clean rag with a little grease or oil and wipe it down. The oily rag will trap the sand/debris onto the rag. Again more harm has been done to a good set of carbs by letting crap from around the filter drop down and make its way to the carbs.
Don't use a vacuum , to clean around the air filter !!!!!
It can draw gas fumes and go boom !
Gene K.

[Lumpy Rider]

Ahhh, this is good information. Thanks Gene. I blew the wells out with compressed air but didn't notice the drain passages.

[Lumpy Rider]

A tiny coolant leak appears to be the culprit. Thanks for the help. Strange the way the discoloration hugs where the head meets the block. Here's a pic of it. The crud in the spark plug well is splash from my grandson dropping a soda near the bike.