I have Jetting problems, need help.

My 06 yz450 is backfiring and poping when I shut down the throttle. Heres what I got, a full two bros exoust system with a boysen quickshot excelarator pump a 170 main and a 48 pilot jet my fuel screw is @ 3 turns out, Ive cleaned my carb and checked my hot choke for extra tension its all good. I was told to richen it up butt how rich do I go, my elavation is about 2400ft, I live in the SoCal high desert.

try a 175 main and move the clip down on your needle and try it. it's all trial and error. if your 3 turns or more it's time to go up one size in the pilot.

read your manual it's in there.

I did have a 175 main jet in there for a little while it did run slightly better untill I raced at GlenHelen, with the altitude change it was back to poping real bad again, I put the 170 back in because I thought the 175 might have been a little too rich on the top side and I needed to richen up the bottom end 0-1/4 throttle.

IMO, you're richer than you need to be already. I run a 165/45/needle in 4 on both my '06's, and they run fine. Yes, they both pop a little, but so what?

If yours is popping excessively, I would look at the exhaust. You most likely have an air leak in it.

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