There is a difference between drilling a jet to get more gas flow on purpose to richen the mixture ... and sticking a hard drill bit in just to clean out some dirt that can be gotten out other ways without messing up what might have been a good air/fuel mixture.
I have drilled out 3 or 4 jets to do just that.
And the best way is with an "orifice drill" set sold to heating and cooling techs for altering the orifices in heating furnaces for different gas types.
They have very fine incremental increases in size and are imbedded in brass hex's with the size stamped on them and are to be operated with just finger "torque".
I have 2 running bikes right now with drilled mains...and one is a ped.
David... If your ped is the type with the exposed cyl head and cyl.... pop the head off and have a look.
Takes 10 minutes at most.