Two riders were taken to hospital with moderate injuries, a broken leg and a broken arm, after the crash at 1.30pm.
Police and emergency personnel attended the crash about 350 metres south of the Taieri Lookout.
The crash was on a blind corner.
While the two injured people were attended to, about 20 motorcycles in a group parked around the crash site.
The group was made up of older motorcyclists in what appeared to be a club run.
Police said inquiries were ongoing in relation to the crash and cause.