I'm hoping someone can help me identify the following film that I would have seen in the early 90's or late 80's. It is a film in the era of Weird Science / Flight Of The Navigator and The Explorers.
All I really remember is that some American teens build a science project which seems to be able to control time or manipulate time. Different characters from different time periods are brought into their own.
One scene I remember which I think is towards the end of the film involves the teens going into their school or university to where this device is located. When they get to the main hall the area has been transformed into a Jurassic jungle environment complete with dinosaurs.
One other very random clip I remember is a scene whereby a bunch of Hells Angels style bikers arrive or are summoned by this device ( I'm hoping this isn't bleed-through from another film...)