Recently, when stopping at a red light, i sometimes (not always) here this like almost metalic thumping noise, sort of like a heart beat pattern..like umm hard to describe but like "duuu-dun.....duuu-dun....etc." I checked my oil recently and it was normal.  I am not mechanically inclined ! so i 'm not sure what could be causeing it.  It sounds like it's coming from the front of the engine, like just infront of my left foot.

Any idea's as to what this sound may be ? or if it is normal ? The only reason why i heard it was cause i stopped at the top of a hill to take a photo the other day, and flipped my visor up, and that's when i heard it. I may have just never noticed the sound before as my visor was usually always down, and couldn't hear it.

An audio track would help of course, but lacking that....

I wonder if it's something in the drive train.  Tight or misaligned chain perhaps?

Does it seem to vary along with engine speed or with ground speed?  (Try different gears.)

it is only faint enough taht i can only hear it when i am stopped and listen for it. So when i am riding along i cannot tell if it makes the noise or not.  What i could do is hold the clutch in, and put it in gear, and rev the engine a bit see if i can get the noise to happen.  I know for sure it happens in neutral (when i was stopped taking the picture), and it happened today on the way to work, waiting at a red light with bike in gear (1st).

oh yeah in case anyone wanted to know, bike is an '03, 2000 km's on it.  I didn't do any mod's or anyhting that could be the culprit of this noise.

OK, I misunderstood.  From your first post I thought you heard the noise while you were stopping - so still in motion.  But you say the noise happens while you're sitting still?

OH!  It must be our friend "camchain endplay".  Now that I'm thinking along those lines, your description of a heartbeat sound fits well.

This noise, if not exactly "normal", is at least considered harmless.  But there is something you can (possibly) do about it if it bugs you too much.

See the thread New GS-500F Owners - Engine noise for others' descriptions, and see the 2nd page for what can be done.

sounds like this thread.....check it out.  I have it too, and mine is a 2004, with only 400 miles.  

http://www.gstwins.com/forum/viewtopic.php?t=9811