on the mc28, with stock setup what type of milage is expected are we expecting?

i recall getting around 190kms on a tank (incl reserve switched), but lately, i've only been able to get 170kms from a tank, reaching the reserve at about 145km. im also feeling noticeable loss in the low end, and the idle doesnt drop smoothly/quickly. bogs a bit at around 1900 for a few seconds, then drops to 1300.
_________________
MC28 sp