It took the under 18s less than a minute to register their first points - Lee Rees crossing for Dale Ford to convert.
Further tries from Luke Williams, Luke Hamilton and two more from Rees put the Scarlets well clear with Ford finishing the half with two further conversions.
The Scarlets made seven changes in the second period but nothing much changed with the side grabbing another eight tries through Jack Roberts (2) Adam Warren (2) George North, Sam Parry, Tomos Ellis Williams and Rhodri Davies.
Ford and Steven Shingler added conversions to complete the rout.
The under 16s trailed to an early penalty from Alex Schwarz, but were soon in control thanks to tries from wing Gethin Hunter (2), no.8 Curtis Morris and centre Rhean James.
John Gardner, Morris once more and Ricky Evans made sure in the second half with Jordan Williams adding three conversions.
Josh Ward crossed for a consolation try for the North who were plucky in the opening 20 minutes but outplayed after that.
The new regional performance manager for North Wales, Marc Roberts is realistic about Gogledd Cymru's results so far. He said, "We were well aware of the challenges participating in the WRU Regional Age Grade Championship would bring. However, the results to date bring extra clarity to the situation.
"The players themselves are relishing the challenge but it is going to take a couple of seasons playing at this level to be really competitive and we are already working with our Under 13s and Under 14s on their conditioning and skill levels in order to bridge the gap."