Yup my 14yr old son uses a DMC Alien system, reed spacer, stock carb, Uni filter direct on the carb throat, +4deg advance, 12:40 sprockets with 18" Kendas claws..He uses Maxmia Castor 927 pre mix at 25:1 #320 main jet. Keeps with the bigger bikes ok on MX.
Looking at fitting a TMXX 35mm D slide Mikuni.