where's the starter on a suzuki GS500

Have you checked the handlebars? Usually you insert the key, turn to on position, then there maybe a on/off button to flick, then you press the starter button which cranks the engine.that is how it works on my Ninja at least.

l asume your referring to the starter motor? you can find it in the middel of the engine behind the cilinders, it is covered with a small cap.