i have a 2003 yz 125 its all stock except the exhaust i have fmf sst pipe and fmf shorty silencer. i just bought vforce reed (V3) and they are on their way. i didnt know what jet size to use. if you have any ideas let me know thanks.

I'm not too up on two strokes. But, you may be able to get by with nothing more than an adjustable fuel screw.

If not, it might be worthwhile to pick up a JD Jetting kit if you have a variety of conditions and temps you ride in.

ok thanks for the help