Following concerns in the community and local intelligence, the local Neighbourhood Policing Team (NPT) applied for and received additional funding from Police and Crime Commissioner to tackle the issue in Canton and Cathays.
The multi-agency operation between police, Cardiff Council, and Immigration, had eight operations deployed throughout August, aimed at tackling anti-social behaviour.
In total, 135 illegal bikes have been seized and will be safely destroyed by Cardiff Council. On average, the confiscated bikes were adapted to reach speeds of between 25-70mph the legal limit is 15.5mph.
Cllr Norma Mackie, Cabinet Member for Waste, Street Scene & Environmental Services at Cardiff Council said: "As a Council we actively encourage people to cycle but what we can't have is people driving illegal, modified electric bikes in parkland and pedestrian areas causing a danger to others.
"Each vehicle that was seized by the South Wales Police could do speeds up to and beyond 40mph, with one bike reaching a top speed of 84mph, which is very concerning.
Read more here.