This is my first post. I have been reading the forums since I picked up my 17 SM in January. The bike has the 3x3 mod, JD jet kit 160 main blue needle 4th position 25 pilot 2.5 turns on the fuel screw, and full rs2 exhaust at sea level (gulf coast). My issue was I pulled the carb yesterday to install an fcr only to realize that the company didn't send the intake boot with the fcr. So I decided to put everything back together so I could at least ride a little. Note prior it was running perfect. Got everything together and went for a ride. If I was in 4th or 5th doing over 50 and went wot then it would buck and sputter otherwise it ran ok. Long story short, I read and tried everything suggested on here. Nothing worked, but last night I found an answer buried in a post about capping off the vacuum line to the petcock and carb. Once I done that the bike ran perfect. So obviously there was a small vacuum leak at wot where the line was on the petcock. The line was on the petcock like normal but im guessing it stretched just enough from removing several times. Just wanted to share with everyone because I was scratching my head since all I did was pull the carb off and put it back on several times.