your new xtrainer 300 should come stock, pre-jetted for 1000-2500 ft, 61-78F. w/ NOZJ needle, #2 clip position, 155 main, 38 pilot, 1.5 turns out from closed for 2501-5000 ft, same temp range, you change the pilot and main to one size smaller, or go 35 pilot & 152 main, leave the needle in the same stock #2 clip position. then once the bike's warmed up, open up the air screw 1/2 turn CCW out, or 2 turns out from closed. for 2501-5000ft, but 40-60f, use same jetting per above, except go up to 155 main, and 1.5 turns out from closed. before you go out and buy jets, a brand new beta should come separately, included w/ your manuals & tools, a 2nd jetting kit with those two smaller size jets and NOZK needle. I could be wrong, so it's best to ask your dealer what comes with the new bike.