GS500: Engine oil | now I have a small oil leak... hey all, Sorry for the noob question, I did a quick search on engine oil and couldn't find an appropriate answer. I need to top up my 2001 GS500 with engine oil.. the book says 10W-40 but i've rung a few local bike shops and they've recommended 15W-50 because of the "heat" in Brisbane. Is this right? Will running a thicker oil damage the engine? Thanks.