Oil change,suzuki gs 500e,1990

Two possible answers here,
1, The starter motor is stuck and the click is just the sound of the relay.
2, Not enough power in the battery to turn the motor over, the lights/horn etc may still work but the starter takes a hell of current from the battery and there may just be not enough to turn it over.

Sounds like your starter relay. Follow the live cable from your battery and you should come across a relay with the wire in and a wire out. Turn your ignition on and short across the 2 terminals with a screwdriver and see if it tries to start. CAUTION: Only do this for a short time until it tries to fire or starts up and do not touch the frame with the screwdriver. If it tries to fire up or even starts, then replace this relay.

Low compression is typically a sign of worn piston rings. The fix is very expensive - overhaul of the engine. You may find it is more economical to replace your motorcycle.

Before you go over the edge, I suggest you have your engine looked at by a professional, who can ascertain if in fact your compression is low and will have a prety good guess at the cause and the repairs required.

You can probably get some more miles from your motorcycle by using heavier grade oil ... if it is worn rings, it will ONLY get worse, it will not improve.

http://www.carlsalter.com/motorcycle-manuals.asp

You have to reset the floats....its not set right and thus the overflow !

The difference between the E and standard model is the fairing and bodywork. the E will have more of the latter.