Yesterday I started up my 400ex, it ran perfect. I was riding in the snow for about an hour and then slid into a ditch and after I pulled it out my air box was full of snow and it ran horrible of coarse, it would not idle and it was just sputtering and backfiring. I took it home cleaned the air filter, and took out the air box and snorkel and cleaned it all out, and this time I put the airbox lid on (it was off before). I rode it for another hour and it started doing the same thing again! So I looked in the air box and it had NO snow in it. So I took it back home cleaned the airbox and snorkel and this time I cleaned out the carb. It fired right back up and ran perfect. Rode it for another hour and it ran fine then I put it up for the night. Today it was goin fine after about 3 hours of riding, now its doin it again! Why is it doing this? I've been riding in the snow forever and this is the 1st quad to ever do this to me! The 2nd time I cleaned it, it had no snow whatsoever in it. I'm gonna buy an outerwear hopfully this will help. What do you think? I just check out my airbox again and it was clean n dry as a bone. I'm thinkin that maybe little at a time snow is coming in through the snorkle and melting through the filter and mixing in water with the gas. I dunno all I kno is I need this to stop its extremely annoying and takes out all the fun of snow riding. Please help.

 

Are you running a K&N without an outerwears? Did you clean out your jets and float bowl? It sounds like you might have shook loose some debre inside.

 

Yeah K&N w/ out and Outerwear. Cleaned out the carb completly. What do you mean by It sound like I might has shook loose some debre inside? The snow? I'm guessing its water gettin into the carb. So Outerwears are waterproof?

 

I doubt your getting snow/water in your carb. You would have to be packing it in there by hand to get it to run bad. What I meant by debre in carb is you said you ran it in a ditch, didn't you? The impact could have shook debre loose somewhere in your fuel system, getting into your jets, follow what I'm saying? If your problem is caused by snow/water, I think your problem could be electrical. Something could be getting wet and shorting out.

 

Yeah but I got it running perfect again after I clean it up. I also kept losing all electrical power yesterday and I figured out it was just a loose positive. I'll clean it up tommorow and tell you if it runs perfect again.

 

Ohh I understand what you are saying about knocking somthing loose. The ditch was 5 feet deep and it was just filled with soft snow. It just barried my quad no hard impact or anything. I thank you for the suggestions though.

 

Cold weather alone can make them run worse.

 

Yeah thats very true but if it was just the cold causing the problems it would constantly run bad. Today it started running bad when I got into the deep snow.

 

hows your old and oil cooler.. sounds to me like your overheating

 

You might be right! I left it in the garage overnight and I turn on the karaseen heater this mornig and left it in there untouched for about 4 hours. It just started right up and ran pretty good. I'll have to see if it stays running good. You think snow and ice is packing in my oil cooler? My oil is waaay over do to be changed. I'm running 10w40.