that seems to be not good, maybe i dont know i have a 99 dr 350 and i could usualy get around 180kms to a tank or maybe more havent realy tried but i think you should be able to get a bit more than what you got
99 Dr 350 - FMF PowerCore 4, airbox mod, jx needle, oversized valves, weisco high comp piston, k&n filter and a few more things