r80g/s high fuel consumption

[cenn8310]

hi all,

i'm new to the air head seen and need some help.

i have been the proud owner of an 83 r80g/s for about 3 months now and ride it 40ks to work and back each day.

i'm getting about 11km/l with an average speed of 60km/h and its starting to get on my nerves.

the bike starts first go without choke and blows a bit of black smoke when revved. it vibrates a fair bit at idle and even more at low rpm, but runs really smooth at high rpm. the plugs are mostly black except for the very tip.

a previous owner has installed bmw 1000 barrels, but i'm not sure if they did anything to the heads.

i have improved the economy from 10 to 11km/l by rebuilding the carbs (o rings and diaphrams) and replacing the air filter with a k and n unit.

i get about 13.5 km/l on the highway.

i haven't replaced the jets as i'm not sure what size to use, seems it has the bigger barrels. i was thinking of using the same cofigeration as the r100rt as it has 32mm carbs. this would give a 135 main jet and 2.66 needle jet.

what does everyone think about this configeration?

also on cleaning the carbs i noticed that both the float needles were quite worn, the tip has an obvious step worn in it where it seats with the carb body. could this be affecting the ecomomy?

any help or suggestions would be great.