According to Official Guinness Records,
The most backflips on a bicycle in a single leap was four performed by Jed Mildon (New Zealand) at Pastranaland in Davidsonville, Maryland, USA, on 12 July 2015.In 2011, Mildon had become the first person complete a triple backflip on a bicycle. This feat was later equalled by James Foster (USA). The pair competed in Pastranaland to be the first to complete a quadruple backflip, and the 28-year-old New Zealander managed it. Both riders had been training for nine months.
For a complete list of 2015 records, please visit 2015 Guinness Records in United States.