Scrambler motorbikes, quadbikes and other small similar vehicles, are mechanically propelled vehicles, which means that they are vehicles intended or adapted for propulsion by mechanical power. As such, irrespective of engine capacity, under Road Traffic legislation, the user of a scrambler motorbike, a quad bike or similar vehicle, in a public place must have insurance, road tax and a driving licence, and must also wear a helmet, with penalties under the road traffic laws (including fixed charge notices, penalty points, fines and possible seizure of the vehicle) for not being in compliance with these requirements.
The category of taxation which such vehicles fall into is a matter for Revenue Commissioners.