The man, in his 30s, had been riding a red and black Honda motorbike which collided with a parked red Peugeot Expert van near to the Royal Mail sorting office on Thorpe Road.
Following the crash, which happened shortly before 11.30am on July 31, he was taken to the Norfolk and Norwich University Hospital with life-threatening injuries.
A spokesman for Norfolk Police said the motorcyclist “remains in hospital” with his condition being described as “stable”.
The spokesman said the investigation into the crash was “ongoing”.
As previously reported, the road was closed while emergency services, including an ambulance, attended the scene.
Police are keen to hear from anyone who witnessed the collision, witnessed either vehicle prior to the collision, or who may have relevant dashcam footage.