The problem with the term "jetting" is it gives the impression that you can change a jet or jets and dial the carb in. Both the main and pilot circuit are more than just jets. The pilot circuit comprises a jet and a fuel screw. The fuel screw adjust the output of the pilot jet. The main circuit comprises the main jet and the needle. The 150F does not have the correct needle and must be replaced to get the proper air/fuel mixture. I highly recommend our PowerUp jetting kit:
http://www.crfsonly.com/catalog/product ... ts_id/3201
Middle clip position on the needle and start with the larger main jet. Get the optional fuel screw and adjust it 2 turns out and adjust from there.
Ken