17 crf 450 decel popping?

Decel popping is a sign of a very lean condition in the exhaust. It can also be caused by running too high an octane fuel as it burns slower than pump gas.
Most decal popping is caused from an air leak in the exhaust. Like putting the exhaust back on after removal with out replacing the exhaust gasket at the head. Most of these are copper and thus look ok, but in most cases they will leak when reused.
A second cause can be a lean setting in the TPS or running a map that is just too lean.

Paw Paw

as far as the modes, Im assuming you mean maps, short press the blue button and it will tell which map its in. one blink is map one , two blinks for 2, etc. To change them, long press the blue button, finger off the button, and it will blink 1, 2, or 3 times depending on which map you change it to. hope that helps.