I was keeping precise fuel milage way back ( About 3 computers ago in 2002).
My 01' model was getting 20k/l heavily loaded on the Hi-way going to rallies etc, gearsack, Tankbag, O/size swag, Tent & Chair plus me @ over 100kg. At this point it was still stock other than a K&N filter.
Pushing along around the ranges near Cairns it would drop to a worst of 15k/l.
Since adding the Dyno-Jet kit in 2004 (opening up the airbox @ the same time) I am lucky to see 15 k/l ever, but it doesn't use much more if U are into it.
Probably averages around 13.2 k/l now with Kerker Meg system, Advancer, ZZR Cams etc. But I love it

.