The crash happened at around 4.50pm yesterday at Cleveland Street in Hull.
Both the rider of the Kasawaki 1100 motorbike and his pillion passenger suffered serious injuries, described as life-changing by police.
The driver of the car, a grey Saab Vector, was uninjured.
Anyone who saw the collision itself or saw the motorcycle being ridden in the area prior to the collision is asked to call Humberside Police on 101, quoting log 426 of 07/05/18.
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