I took my 2001 gs500 to a battery store today because my battery keeps going dead.  They told me my charging system is working but I have a bad diode?  He did not know what or where it was on the bike.  Anybody ever have this problem? Dont really know where to go from here other than the dealer, i would like to fix it myself.

"charging diode" probably sloppy terminology for regulator/rectifier (rectifier is a diode, you see). The thing just called a diode on the wiring diagram is not it (it's just a diode, and part of the starting safety system).

Try this from the FAQs section of the board:

http://gstwins.com/gsboard/index.php?topic=38480.0

Thanks alot I was a bit confused but this will help me out big time.  I am lost with alot of this stuff being my first bike.  This site kick ass
Thanks again.

Charging diode??   He is about 40 years out of date 

As well as doing the tests try disconnecting the reg/rect at the plug when you leave the bike for any period of time, like overnight, and see if the battery stays up. As well as not charging the battery a duff reg/rec can also short the battery via ground and cause it to drain over a period of time. In the worst cases the reg/rec will still be warm to the touch owing to the current flowing through it to ground even when the bike has been stood for hours

Referring to the charging system, the diode is like a one way valve.  It only allows current to travel in one direction.  When the alternator is generating current it's in the form of alternating current (AC).  The diode prevents the current from traveling back to the source and is converted into direct current (DC) which is the type of current our bikes run on.  Our GS's have a total of six diodes in the rectifier.  If one or more of them are bad, your charging system may not get the required voltage to fully charge your battery. So by the battery store saying your charging system is fine but you have a bad diode isn't exactly accurate info.  I'm thinking they mean't a bad cell in the battery.

A big thanks again to all of you.  Ends up the brand new battery was not so ggod, they replaced it and all is good now.