The guys at Yamaha told me go up to a 280 main from my 260 when the temp drops below 50. I did what they said and changed the jet. Now, when i do a plug chop, the plug is a little brown and not wet? Before, with the 260 in warmer weather the plug was brown and wet. I would think 2 sizes up on the main would make it rich? Also, it wont idle. By the way i have an fmf pipe and silencer. Any suggestions?