Mr Pilkington was walking on a pathway when he heard the motorbike coming from behind but he couldn't get out of the way and the motorbike hit him.
As a result Mr Pilkington suffered extensive injuries to his right hand, cuts to his legs and facial bruising and needed hospital treatment, Sergeant Lawrence said.
Hart was later found by police and told them he had taken the motorbike to go joy riding.
Judge Stephen Harrop said the charges against Hart were serious, carrying maximum terms of imprisonment ranging from five to 10 years. He said Hart was a young man with no previous convictions and that he was not prepared to sentence him until he had more information, including a victim impact report.