Quad won't start

[JDMThoughts]

Alrighty so Saturday I finally had a whole day to finally ride my new quad. I took it out for about 2 hours. I rode and hit a muddy area in which I got stuck, but left the quad running and physically pulled it out. I kept riding for about another hour or so. I get to my local pit and shut it down and take a break, then I start it up and ride some more, finally I come home and wash it off thoroughly, and I go to start it up to bring it around the back of my house and it won't stay running. I have the choke lever all the way up and it will idle maybe for 2 minutes, and when I try to put the lever back down it stalls. I have tried to give it gas and it feels like it is stumbling and then there is massive popping noise coming from the exhaust and then it usually stalls out. I am unsure of what is wrong, I am thinking maybe clogged/soaked filter. Possible water in the carb, not really sure as this is my first atv and this is the first problem I have ran into with it. I have already went through 2 tanks of gas this week from periodic riding, so I know the fuel is fresh and is new. I thought maybe I got some water in the muffler that traveled it's way backward so I lifted the quad up and checked to see if anything was gonna come out. I do have the factory service manual to try the troubleshooting but I wanna see if I can get a solid answer from you guys to pinpoint it without going over everything on the quad to find the problem. Thanks for any helpful info in advance.

[Les Davis]

I know your looking for a better answer but I would start with the air filter and once that is deemed ok, I would move onto the Spark Plug. Sounds like you may have got it wet and fouled it. If I was a betting man, I would say a quick change of the spark plug and you'll be back up and running. I had this problem on my old 400 many times when riding in wet conditions.

[400eXr1d3rZ]

Sounds like you have gunk in the jets. Although I would clean out the air filter anyway, aswell as the carb.

[JDMThoughts]

Alrighty, I guess sometime this week I am gonna go over the the quad and check the filter to see if that is ok, and if that is good I am gonna check the plug, I have absolutely no knowledge of carbs so I am gonna save that for last as it is will be the most difficult thing for me to do since I am not familiar with it at all. Thanks for the help and if anyone else reads this and has an idea let me know.

[onesexyrider609]

Definitely check the plugs. Especially since it is cold, on start up and idle, it seems like my 400 loves to foul plugs now. So just pop a new one in, and it should start right up.

[brianr134]

Do you ride with your airbox lid off? If you do then likely you got water in the carb or junk in your jets (as was mentioned). The popping to me would seem like an indication of you running lean (clogged jets) or not firing completely. Have you checked inside your airbox already? Don't be intimidated by the carb, its not that hard to take one apart, just do it in a cleaner area. Just make sure you turn the fuel to off, then pull the small black rubber hose out from the swingarm (I believe the hose runs down by the swingarm) and then drain the carb into a container by using a small flat blade screw driver and back out the screw a tad thats located just below the choke.
HMF has a nice info guide with pictures about the 400EX carb on the earlier models. http://hmfengineering.com/forums/showthread.php?t=497

Good luck :)

[JDMThoughts]

Me being new to this, I would say the lid is on, because the quad is virtually stock. There have been no modifications made to it. Thanks for the link to the HMF carb guide, that should help me as well as the factory service manual I already have for it. Thanks for the suggestions and ideas, I guess I will get cracking on it tomorrow or as soon as possible. I'll let you guys know what happens.

[troutman561]

Also, did you pressure wash it to clean it, because thats no good for quads and you may have gotten water in some places it shouldn't be from the pressure... just check all the thing everyone has mentioned and if it isnt fixed you may have a problem you will have to see the dealer about...

[JDMThoughts]

No pressure wash, just a regular hose with a misty setting not a jet stream. I washed it as I would wash my car. I wouldn't pressure wash my car so I wouldn't pressure wash my quad either especially with the motor exposed in the open.

[JDMThoughts]

Okay so 3 hours later into the endeavor, I find the air cleaner housing drain tube completely packed with mud. The filter which I am now aware of being a K&N is completely caked with mud so I have since cleaned it but have not re-charged it as I think I am gonna go back to OEM. Spark plug was completely black and new one was installed, which required a trip to the dealer for the spark plug tool. I had a difficult time getting the carb off but it's off and I checked over the whole thing minus two areas, because of stubborn screwson the throttle valve arm and one screw on the float chamber. Overall everything else looked clean, and I took the carb to the local performance shop for them to clean it if it's clogged. Hopefully I should be up and running in a day or two, I will keep everyone posted on the outcome.

[JDMThoughts]

So yea, I changed the plug which was fouled, changed the piece of **** K&N filter to a Uni. Cleaned the carb out and then had it checked by the local performance shop because I wasn't 100% positive I had everything right, even though I did. Brought it all back together only for it now not wanting to start and I feel like I went backwards. So this week I am dropping it off at the local shop and letting them take care of it, I can't afford to waste anymore personal time working on it as I have a hectic schedule coming up. I'll post any more info when the time comes, thanks for the help guys, but apparently something else is wrong with the quad that hasn't been mentioned.

[js600]

might be a stupid question but is the gas turned on? sorry, no offence intended but i like to check the easy stuff first...J

[anderson3064]

Originally posted by js600
might be a stupid question but is the gas turned on? sorry, no offence intended but i like to check the easy stuff first...J

not a stupid question at all but I swear i never did it. also coming from a guy who is known for getting in a hurry, did you put the plug wire back on, turn the key on, and check the fuse by the battery box. my sons 300ex was doing the same thing from riding in the mud and his box and iar filter were wet so i turned the gas off and stood it on its end overnight. cleaned the airfilter and woohoo she fired up

[JDMThoughts]

I am not offended, but I did check the fuel and the thing just isn't working right now. Not sure, I am gonna overlook the battery, ignitor and fuse box. Maybe something will come up, otherwise the quad is going into the shop on Friday as planned. I am hoping this next bill isn't gonna be that bad. I am already in 140 dollars and it's still not running.

[anderson3064]

ok dude. did you check the carb. the jets are mighty small and if one grain of sand or dirt gets through the no fuel. it might be worth your while to check the carb before getting burnt.

[Les Davis]

this might be a long shot but check the nuetral wire that connects to the left side case located around the shifter. I had mine come loose and had problems with my 400 starting. Pull from pin on crankcase and clean and make sure the fit of the connection is snug. Like I said, this is a long shot but worth checking before you send to the dealer$$$$$$$$$$

[JDMThoughts]

Originally posted by anderson3064
ok dude. did you check the carb. the jets are mighty small and if one grain of sand or dirt gets through the no fuel. it might be worth your while to check the carb before getting burnt.

4 post up I mention I took apart the carb and cleaned it. I dropped it off at my local performance shop because there was one area I wasn't able to get to and the shop cleaned it for me. So the carb has been cleaned twice. I tried standing it up and I checked back on it a few hours later and it started but died quickly. I have been racking my mind every evening after work and am just fed up with it. I went through everything short of taking the motor apart. I am dropping it off tomorrow at the local performance place to have my wallet raped to the tune of probably 400 or more. It is what it is, I guess from now on I won't ride in mud, or wash my quad, just use detailing rags and a spray bottle. I must say this is leaving a very sour taste in my mouth thinking I own one of the most reliable quads on the market, and taking crap from co-workers with Banshees doesn't help.

[anderson3064]

this would be a long shot to but maybe you got water in the tank. not sure. when i said my sons fired right up it did but now it doesnt stay running, but we are tearing it down for the winter so i wont know anything till march. i would think maybe watered down gas or a clogged vent hose.

[JDMThoughts]

So I got the quad back and the damage was 270, I can't complain with that. They went over the bike completely, helped tune the carb to start better in the cold, a valve adjustment was needed and they found that the big culprit was a bad wire in the spark plug boot which they repaired. Tightened up anything that was loose or looked suspect. After the initial ride it feels so much more powerful now then it felt before I am guessing they got the jetting almost spot on. There was a whole list of problems with the bike, such as the bike was a quart low on oil but the oil was fresh, so I guess the previous owner didn't circulate the oil to go back and double check if it needed more or not. I have only put two hours on it since ownership. there was also an air leak in the carb that wasn't helping issues either. all and all I am happy to be back with a good operating quad and I can now ride it without any worries. I figured I would post this up so in case someone checks they might wanna go over their spark plug boot as it being shorted out in my case.