Let’s go over the motorcycle licence categories. In today’s licence system a new rider can start their motorcycling career at the age of 16 with the AM licence: 50cc motorcycles (scooters) after passing theory and practical exams.
At age 17 an option for proper motorcycles open up with the A1 licence. Anything up to 125cc and 15 bhp is allowed.
The category above that, A2 can be obtained at 19. This licence allows any motorcycle not exceeding the power output of 35kW (equates to about 46-48 hp) and a power to weight ratio of 0.2kW/kg. There are plenty of smaller displacement bikes on the market that compile with these numbers by default. However, if your dream bike falls outside of this category, chances are, you will still be able to ride it. As long as a motorcycle doesn’t exceed double of the power limit, 70 kW (or 94 hp), it can be restricted down to 35 and ridden with the A2 licence.
Anything above 94 hp will have to wait for the full A licence, which of course allows any and all 2 wheeled machines to be driven. According to EU regulations the A licence becomes available at the age of 24.

Restricted bikes in practice:

It is obvious that any motorcycle that comes with a stock power output of 35 kW or less is fair game. However, you may have doubts about the practical elements of riding a more powerful bike with A2 licence. More specifically, how does it work when a police officer pulls you over and you’re riding a bigger, but restricted bike.
When you install a restrictor kit in your motorcycle you also need to get your bike’s registration updated. Generally speaking, the number in your bike’s data sheet will be the only factor the police will have to determine your bike’s power output. So as long as it compiles with the numbers stated above, all is good.