Two Questions - Now MPG

[Ped]

Riding at the legal speeds (80 km/h - (50 mph)) plus a little extra 
never takes me under 20 km/liter (47 miles per US gallon).

Motorway speeds (110 - 130 km/h (68 - 81 mph)) is usually around 18 
km/liter (42 miles per US gallon).

The record so far was 24,2 km/liter (57 miles per US gallon) during a 
trip through Poland with a XV 250 behind and speed traps every 10 miles 
or so.

The low was 13 km/l (30 miles per US gallon) on a German Autobahn with 
170 km/h (105 mph), strong headwind and loaded with passenger and 
camping gear.

I have 102.000 kilometers (63.400 miles) on mine now. Carbs, jets, 
exhaust etc. is stock.

Ped
'96 "Black Stealth" GPZ
Denmark

BTW: There has been a distinct smell of gas around the bike lately. I 
just found out tonight that the petcock is leaking. No, it's not 
flooding the carbs or anything, it's a leak in the petcock itself or the 
mount. I have to take a closer look one of these days.