Well I gave up eco'ing after about 250m where I'd managed 3.2l 100km up to that point. From there on I hit the French autoroutes & cruised at 85-90mph all the way there & back. The whole trip average was 4.2L (67mpg imp)
Best part is not having to stop for fuel! It pretty much gets to the Alps on a tankful
Mucho fun on this Snow Scooter for a couple of days too