jettig 300

[300exr]

I have an HMF slip on for my 300 and I went up 5 sizes on the main jet like it said to do and left everything else the way it was.
However, whenever i let of the gas it backfires alot. What do I need to do to fix?

[VTRJason]

Turn your idle mixture screw out to 3 turns. Mine still pops a little but not too much.