I was suffering same like you all less mileage about 25 km. So I took my Scooty back to the service station and asked them to check the spark plug gap. Actually spark plug in Activa is idrum. There was a good amount so we reduce the gap.
Activa factory mistake. Please let your Activa fuel meter come to red E. I have checked that it has 1.5 liters reserve.
I have calculated my mileage its 62 on road with driving on 50- 60 speed.
For more info contact me-
8586047631 love to help you all!