Police were informed of the accident on the bypass road at 10.20pm.
A 15-year-old boy suffered a broken left leg while a 17-year-old suffered severe head injuries. Their motorcycles were severely damaged.
Police said they were not sure how the accident happened but believed one of the motorcyclists made a u-turn causing a high-speed crash with another vehicle.
Local residents told police that 50 to 100 motorcyclists raced on the road each night.