EMERGENCY services were called to the A52 between Hogsthorpe and Mumby at 8.20pm on Monday, following a collision between a Renault Grand Scenic and a Baotian 125 motorbike.
The rider of the bike, a 20-year-old man from Ingoldmells, suffered multiple fractures and was taken to Boston Pilgrim Hospital in the first instance before later being transferred to Queens Medical Centre in Nottingham.
His condition is described as serious but stable.
The Renault was being driven by a 40-year-old woman from Alford and her passengers were two girls of 11 and two and a boy aged eight.
All were uninjured.
Anyone who witnessed the collision or who saw the vehicle prior to the incident should contact the Collision Witness Hotline on 01522 558855.