The collision, involving a male motorcyclist in his 30s and a female pedestrian in her 60s, took place at around 5pm on Saturday (May 9).
A Lincolnshire Police spokesman said: “Both the rider and pedestrian received serious injuries, not believed to be life threatening.
“An air ambulance took the female to hospital, and the rider was taken to hospital by land ambulance.”
The road was closed for around two hours while the emergency services dealt with the incident.
A spokesperson at the Lincs & Notts Air Ambulance said: “Our Air Ambulance arrived on scene in just 17 minutes, a journey that by land could have taken up to an hour.
“Our crew treated a patient before airlifting them to Hull Royal Infirmary in just 14 minutes, a journey that by land could have taken up to an hour.
“The life-saving work of the Lincs & Notts Air Ambulance is only possible thanks to the generosity of local people who continue to support our charity.
“As we monitor developments with the COVID-19 pandemic, we remain committed to providing a pre-hospital critical care response.”
• If you have any information about the collision, call Lincolnshire Police on 101 and quote incident number 300 of May 9.