According to the State Police at Frackville, the crash occurred around 4:00pm at Exit 138 (McAdoo).
Police say John Bachert, 45, of Lansord, PA was riding Harley Davidson Supper Glid and merged onto Interstate 81 Northbound at Exit 138.
He entered behind tractor trailer and the overflow wind current of the truck caused Bachert to lose control.
Bachert drifted into the passing lane and made contact with the rear of a Dodge Caravan driven by Thomas Campbell, 75, of Monticello, NY.
After making contact, Bachert and the motorcycle went off the west side of the highway where Bachert struck a culvert ejecting him.
Bachert was reported to have suffered serious injuries and was taken via McAdoo Ambulance to an area hospital.
McAdoo Fire also assisted at the scene.