Modern Vespa

Hello,

I have a Piaggio Liberty S 50cc 4T 3V year 2021 and on idle the engine feels like it skips a beat, it has a small stutter and I can feel it when I stand on the scooter or holding the brakes, this only happens after the engine gets hot and it's not regular it does it randomly at different time intervals, I am pressuming that the valves needs to be checked as it is a new scooter with just 1500 km milage.
Any ideeas what might cause this ? It's annoying ...

What's your owners manual say for maintenance especially a valve check? My 2016 Sprint maintenance chart said at 600 miles (1000 km) to check valve clearance

I believe that has been done already as I bought the scooter with this milage but I am not 100% sure, I will bring it to the mechanic in the next days, just wondering if anyone had this sympthoms and could give me an answer beforehand.