450 EX/c RFS Carb Jetting & tuning

I have a 05 450 EX/C and have noticed that the spark plug electrode is very black and suited with carbon. I believe that this is from a rich mixture. It has about 100 hrs on it and gets an average range of 33 to 40 miles on a single tank of fuel. I have adjusted the vales several times and the clearances are correct.

What are the proper steps to tune or adjust the carberator?


Recent purchase? Always been this way? Have you had the carb apart?? Please open the carb, post what;

pilot jet (up a well just forward of the main jet)

Main jet Bottom center

remove the needle and note the 5 letters stamped on the side just below the clips, if no letters check for paint on the top of the needle

Remove the carbs clamps, pull the carb back and look in from the engine view, is there a 1/4 hole near the bottom, does not go all the way thru

In the FAQ at the top of this page read carb setup 101 and AC pump 101

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