The most recent speedway event, the Demo Ramp Derby and FMX Display, was soured when seatbelts and batteries were stolen from derby cars after the event.
Last Saturday night or early Sunday morning, the only valuable things left on most of the derby cars were stolen, Mr Gillon said, which was really disappointing.
Read more: City's home-moving businesses on the up
"The event was a huge event, we had good spectator numbers, there was a lot of excitement with the freestyle motocross guys."
Mr Gillon said he had learned from the thefts, and next year he would make sure security guards were stationed by the derby cars after they came off the track.
Despite the ups and downs, speedway's future at Baypark was not at risk, Mr Gillon said.
"Speedway is an essential part for Bay Venues to get a return on the facility.
"Rugby's not there any more and there's very few events that they can hold inside the speedway stadium. You aren't going to have 15 or 16 concerts in the space of six months, which is how many speedway events we have," he said.
Bay Venues had been exploring other events for the stadium for years, "but ... speedway is the most essential ingredient to the stadium being successful."
Read more: Seven-year-old to cross Pacific for life-changing surgery
Baypark general manager Ervin McSweeney said it recognised there had been many up and downs but speedway was a very important part of the stadium. "Bay Venues will be trying to get other attractions but would not be pulling the plug on speedway by any stretch," Mr McSweeney said
Today would be the speedway finale, the Fireworks Extravaganza and Harry Fredrickson Stock Car Gold Cup, all of which Mr Gillon said was "something not to be missed".