Many things can cause a snowmobile engine to back fire. Ignition coils ( spark plugs, coils) or water in fuel. Check these and maybe it will solve your problems.
unburned fuel in the exhaust ignites
Unburned fuel in the exhaust system causes the backfire from the exhaust pipe.
I think you are hearing pressure pops. Not a backfire.
a backfire is caused by incorrect timing or not enough back pressure in the exhaust pipe
It's lean.
It's lean.
Backfire is normally caused by engine out of time, or spark plug wires installed incorrectly.
bad gas
Too much PSI.
Out of time.
Your car is running too rich.
there could be many reasons, but you need to elaborate on your question, that is too vauge to answer... is it a snowmobile? is it an atv? are the spark plugs clean? is fuel flowing to the carb? does it backfire?