According to Official Guinness Records,
The largest parade of Indian Motorcycles numbers 274 participants, and was achieved by Indian Motorcycle of the Twin Cities Minnesota & Welch Charities (both USA) in St. Paul, Minnesota, USA, on 19 August 2017. The organizers broke their existing record, set a year earlier, by nine motorcycles.
For a complete list of 2017 records, please visit 2017 Guinness Records in United States.