It means nothing keeping track of how many kms you get if you don't know how many litres you put in. Also you are going to get poor fuel economy running at 70-80mph there is far too much wind resistance. Run it at 60mph or below and you will get much better.

The best i've seen from my bike is 3.3l/100km which was damn good i thought. On my 2006 zx6r i get 4.2l/100km.