I get a bit over 18.5 km per litre on the highway from my 865cc with pipes/air filter/re-jet/one shim on the needles.

About 45-46 mpg a U.S. gallon.If I did the calculations right.

Or the same 5-6 more that you had,before the B.B and mods..
That's very good mileage for the power you have.

Dinosaur.

"Oh Man I only ride 'em.I don't know what makes 'em work". Donald "Oddball" Sutherland

"Don't let the bastards get you down". Kris Kristofferson

"I am only paranoid because everyone is against me". Larry [Frank Burns] Linville