A Manitowoc man was struck by a motorcycle on Memorial Drive yesterday afternoon. At around 1:35 PM, the 75 year old man was riding his bicycle across the street, when the motorcycle, driven by a 20 year old Valders man, struck him. According to eye witness accounts, the Manitowoc man violated the stop sign on Lilac Drive, causing the accident. The Valders man suffered only minor injuries, while the cyclist was transported to a hospital in Green Bay for potentially life threatening injuries. Both men were wearing their helmets.