A grandfather and his granddaughter related to a large Manteca family lost their lives late Sunday afternoon from carbon monoxide poisoning at the Clements Stampede Rodeo grounds in the 19800 block of Highway 12.San Joaquin County Sheriff’s spokesman Deputy Les Garcia released the names of the victims Monday afternoon as Richard (Rick) Leroy Kovacs, 56, and Jordan Lynn Kovacs, 14, both of Copperopolis.Kovacs had moved from Manteca to Copperopolis a number of years ago where he bought a 20-acre ranch and had been mentoring his granddaughter to become an accomplished teen rider. He was always there to cheer her on as she rode like the wind, family members said.The Clements region of the California Gymkhana Association had rented out the rodeo grounds for the weekend to host the first of several planned fall horse competitions. A Kovacs family spokesman said an afternoon barbecue had been set up during the event with the spent charcoal apparently being put in the back of their horse trailer.