i just completed a 120 km(approx. 72 miles) yesterday in rainy conditions with lots of moisture.after encountering some water, my
machine starts to backfire for the rest of the trip accompanied with a signifigant loss of power.these were not deep stream crosssings.
just huge mud pudles and not deep.
i checked the plug and airbox.no problems.

any suggestions of what might be wrong would be appreciated

2001 arctic cat 250 4x4

 

crown; Sounds like an ignition problem to me. If you can get it to misfire when its dark outside, look around the plug and plug wire to see if you see any blue arcs or a halo effect. If you do, the wire is bad. Then again you could be getting water inside the stator housing or into the igniton sensor or pickup. Pull the covers and check.

 

Sounds like a connector got some water in it. Now that its dry, it should run better.Or does it?
You could use a spray bottle with water, and spray down each connector, and then test drive. Eventually youll find the one, and then pack it full of synthetic grease, ( silicone grease), thatll keep it corrorsion free, and dry. Also put a bit of the grease around the spark plug and cap, and then itll waterprof that too.
Also drain the float bowl, into a clear container, and let it settle out. If theres water in there, that would cause rough running too.