2005 yz250f popping on decel

A few different guys around here have told me that my bike popping on decel is normal. A local mechanic told me that they usually dont re-jet the newer 4 stroke race bikes, they just adjust the fuel screw. This doesnt make sense to me, we are at 5600 feet and all of my riding is done at higher elevations. I tried re jetting from a 182 (stock) main jet to a 175 and moved the needle clip up one space. the bike seemed to have more power and was quicker on acceleration but I could tell it was running too lean and the popping was worse. went back up to a 180 main jet and set the needle back to 4th notch (stock), less popping but seems like less power too. i tried playing with the fuel mixture screw with the 180 jet but it didnt make much of a difference. Any help would be helpful. I do mostly trail riding and the popping is annoying, especially for the poor guy behind me.


PS bike starts up easily just about every time with both settings

You are adjusting the wrong circuit for popping.

If you had more power with the mods you tried then stick to it.

The popping is the pilot circuit. You either need a bigger pilot or turn fuel screw out a bit.

3-5 decel pops is good. More than that and you need to adjust the fuel screw like Thommo said.

Your mechanic seems lazy. At the elevation you ride at, running the correct jetting will help make your bike run at it's true potential. Of course, you don't need to re-jet as long as your happy with the way the bike is running. And like the others have said, you are adjusting the wrong circuit when you were trying to lessen the decel popping. Decel popping is the pilot circuit, which is lean, and needs to be richened up using either a larger pilot jet or by turning out the air/fuel screw some more. Is the crush washer on the exhaust in good shape?

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