The incident happened in Keptie Road, last Monday (September 20) between 6pm and 6.30pm.
A Police Scotland spokesperson said: “The 14-year-old boy was allegedly assaulted by a man who initially remonstrated with him regarding him cycling on a pavement, before forcibly pulling him off his bike and threatening him.”
This resulted in ascuffle, which was ended when a member of the public intervened to assist.
The man then walked off in the direction of Timmergreens.
He is described as between 45 and 50 years of age, about 5ft 9in tall, of stocky build with short grey hair, and at the time of the incident he was wearing a black jacket and black bottoms, and a beanie-type hat.
The spokesperson added: “We would also like to trace the member of the public who intervened and assisted the complainer.”
Anyone with information about the incident, should call 101, quoting incident 3117 of September 20, or speak to any police officer. Information can also be given anonymously through CrimeStoppers on 0800 555 111.