Police said late on Tuesday afternoon that the 21-year-old’s condition remained stable.
They have not named the motorcyclist, but they have confirmed that he is a man.
He was riding a white Suzuki GSXR motorcycle when he collided with a HGV tipper truck at the junction of Rue Frairies and Rue des Buttes – near The Last Post pub – in St Andrew’s at about 16:00 on Monday.
All emergency services were called to the scene.
Police have released a revised statement requesting witnesses.
“Investigations into the incident continue and officers would like to speak to anyone who witnessed the collision – particularly people who may have dash cam footage of the road traffic collision itself or the preceding moments,” they said.
“Please contact PC 174 Potter on 01481 222 222 or call Crimestoppers anonymously on 0800 555 111.”