AOA brother, you are right, it is not advisable to drive it on this speed. I also just checked it for 5/6 mins but normally drive it around 100. And that's only possible if the veh is 100% fit in terms of suspension, balancing of the wheels, the tires, the front ends, leaf spring bushes etc etc and lastly the most importantly, the condition of engine. In my veh, i have the thermostat valve installed, the radiator fan runs on a viscous clutch which on highways remains idle resulting in no load on the engine.
About the average, in local (islamabad) it gives me 15km/ ltr and on motorway, it gives me around 12km/ ltr. This happens normally in smaller engines which run on torbo.
Regards
