Hello to everyone. My first time here and I really need your expertise about GS500. I'm planning to buy a second hand bike. How would I know if I'm buying a good one. Please help. Most of the times I always regret things when my purchase don't go well as I expected. I only want to enjoy riding the bike to and fro going to work and home. Thanks Emmanuel of Sydney, Australia.

Scan through the information on this page for some things to look for in a used bike:
http://www.clarity.net/~adam/buying-bike.html

The other best advice I can give you is to bring someone along who knows motorcycles to help check it out or set up an inspection with a dealer or mechanic before you buy it.

+1...  Take someone who knows what to look for.  And some common sense.  There seems to be more likelyhood of something being screwey if the bike has been heavily modded, especially by a novice.  I got mine stock, did some mods myself, and see how easily someone who isn't careful could screw things up.