i am a total newb when it comes to servicing a motorcycle or anything to do with the workings of one. So here is my question...i had my 18000k service done the other day(oil and filter change) and i have seen through my oil inspection hole that the colour really hasn't changed.it is dark in colour. i was looking at a couple of bikes today at another bike repairer(got a new rear tyre) and noticed on the bikes that were being serviced out the back had a yellow oil, well... clear oil. are there different oils that can be used in bikes???