Detective Senior Constable Wayne Ryan, of the Warrnambool police Criminal Investigation Unit, said a businessman selling motorcycle-related items had set up a stall in the old grandstand to coincide with the visit by high-profile Crusty Demons riders Seth Enslow and Bubba Chiasson.

Their ride didn't go ahead at Lake Gillear due to the inclement weather but the stall was set up.

Detective Senior Constable Ryan said that overnight Saturday entry was gained to the old grandstand after a window was smashed.

"The Crusty Demons were in town and the businessman was selling motorcycle gear including leathers, gloves, protective gear and other items such as t-shirts," he said.

"The stall was open Friday and Saturday. Some time overnight Saturday a window was smashed and a substantial amount of motorcycling racing paraphernalia stolen.

"The room was full of clothing. The thieves would have needed at least a van to load up what they took. The value of the stolen goods is about $8500."

Detective Senior Constable Ryan said that the Old Collegians Football Netball Clubrooms was also broken into on Friday afternoon.

He said that at 4.40pm a silent alarm was activated after a brick was thrown through a window. Nothing was taken.

Detective Senior Constable Ryan said that the clubrooms had been broken into a couple of times this year and had been a regular target during the past few years with especially young offenders trying to obtain alcohol.

He said club officials were considering upgrading the security system.

Anyone with information about either offence is requested to contact the Warrnambool police station or Crime Stoppers on 1800 333 000.