06 yz450f jetting

Ok guys got a question got this bike last fall and only got to ride few times before cold weather set in. Guy I bought it from had no clue on pipe brand or if anything had been done to bike well while riding on decel it pops and cracks like crazy gets better the more u ride it but still pops throttle is very unresponsive runs the best on choke. So figured I'd check and reshim the valves and why I was in there decided to take off carb give it a good clean and put new kit in. The Jets that are in it is a 42 and a 178 main seems little rich to me would you go back to stock setting on it and go from there. Have no clue what brand pipe is on don't look like the stock pipe but it maybe the Jets have what looks like a star stamped on them. Thanks for any input

Forgot to mention if it sets there and idles or even just at low rpms like turning the bike around the header pipe will start glowing red

It's lean and then rich.  Start with a #45 pilot, a 168 main, and be sure the needle in the carb slide is in the 4th position. Base idle screw at 2 out to start, trim from there.

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