visit http://www.duratrax.com/pdf/index.html and download the manual. read the section on needle valves
i think the default out of the box the high speed is set at 2 turns out and the low speed is 1 1/2 turns

after breaking the high speed should be set at 1 1/4 - 1 3/8

for more read the carburetors setting section.. good luck