The collision happened on the A542 from Llandegla, which leads up to the top of the pass - a well-known route for motorcyclists - just after 2.30pm on Sunday.
It involved a silver-coloured Suzuki Swift car and a blue-oloured Honda CBR motorcycle.
North Wales Police said the motorcyclist suffered serious injuries and was taken by the Welsh Air Ambulance to the specialist trauma unit at the Royal Stoke University Hospital.
Sergeant Medwyn Williams from the roads policing unit said: “I hope the motorcyclist makes a good recovery. I am appealing to anyone who was travelling on the road at that time between 2.20-2.35pm who witnessed the collision or may have dashcam footage of either vehicle prior to the collision to come forward.
"I would also welcome anyone who may have been travelling that route that has dashcam to contact us. If you have any information, please get in touch via web chat or by calling 101, quoting reference 21000413584.
"The road was reopened at 7pm.
"We continue to urge drivers and and bikers to enjoy north Wales safely. Drivers - please look out for bikes when turning, whilst at junctions and when changing lanes. Bikers - please ride to the conditions, stick to the speed limit and know your capabilities," Sergeant Williams added.