Is it illegal for a motorbike driver to view Google Maps or a map?
Maybe. It certainly depends on the jurisdiction in which he is driving. It may depend on the device on which the maps are displayed. I recall a case (but sadly not the jurisdiction, sorry) where its legal for car drivers to use electronic navigators, but not the same application on a mobile phone. I would suggest contacting your local police and asking them. Get a reference number for the call; if they tell you how do to it legally, and some overzealous policeman stops you anyway, then you will be in a much better position if you can quote the call reference.