Two motorcyclists died and two others were injured when their bikes were hit by a truck on Tuesday in the Udhampur district.   Police said that four youths riding on two separate motorbikes were going towards Mata Sukrala in Billawar on the first day of Navratri were hit by a speedily driven truck near Dudra Nala in Roun Domel area of Udhampur. Critically injured, all four were rushed to the Government Medical College and Hospital, where two of them were declared dead.  Police said that the truck driver was taken into custody, and a case has been registered for further investigation.