idle problem

[Steve89x]

Hey guys I just bought another 400 cheap, its an 01 and completely stock the guy who I bought it off of never beat the quad and always took good care of it. It has been sitting for about the past year or so though, I drained the tank and changed the spark plug and cleaned out the Carb. It runs good but won't idle. It idles great on choke but once you turn the choke off it dies instantly. Any ideas on what this could be? The idle screw on the side of the Carb is maxed out...is there another adjustment for the idle inside the Carb if I take it off again?

Thanks

[jman7290]

Sounds like its running rich to me, is the air filter clean? If it is you might want to message CJM for some jetting tips. He is the man on here!

[Steve89x]

No the air filter is dirty but I didn't think that would affect the idle. I've never had that affect it before. I'll try cleaning that tomorrow first and go from there, maybe open the Carb up again.

[#484]

Did you clean the carb while apart, did you clean the pilot jet? The screw that you want to adjust should be under the carb, on the bottom in front of the bowl towards the intake. That is the mixture screw for the idle circuit. I think what you are adjusting is for the idle speed. It sounds like it may be lean since it runs with the choke on. Check the screw under the carb, a good place to start would be about 1 and a half turns out from from all the way in. That might not be the perfect adjustment but should get it running with out the choke. Good luck

[Steve89x]

Yes I did take the Carb all apart and clean the jets and everything. It was the idle speed I was adjusting at first. Tried adjusting the a/f screw but had no luck getting it to idle. Started at about 1 -1/2 turns out and tried up to about 2-1/2 turns out... the carb needle is on the 3rd clip. Like I said though I know the guy I bought it off of. He never adjusted or played with the Carb before he just got on and road and the quad is stock.

[CJM]

Check the throttle cable up at the bars, if it isnt adjusted far enough out the quad wont idle period.

I would also take off the side cover and verify the idle screw is actually moving the throttle butterfly like it is supposed to. The screw is connected to a wire that pushes the throttle butterfly open slightly.

Also FWIW:
The only time I can get a stock EX to idle and run is to warm up the hell out of it while holding the throttle-even whn its 80F outside. Once its warmed up it idles fine.

Id also reclean the carb, check the plug again as well too. What jets are in there-your sure they are 100% stock?

[Steve89x]

I was already playing with the cable at the bars. I tightened it up so there was no slack in the cable but the adjustment was pretty much unscrewed all the way out. And yes positive it's stock. I got it from a family friend who bought it brand new in 01. It had the original air filter in it too that disinegrated when I tried to clean it haha.

[CJM]

So you have no air filter on it now? Without an air filter it wont run at all.

[Steve89x]

No it does, I put another one on.

[Steve89x]

I'll just keep playing with the Carb. I was just checking to see if there was something I was missing with this.

[CJM]

Everything seems like its done right.

Tried running on reserve? Maybe the fuel petcock is clogged up?

[Steve89x]

Yup ran on "on" and reserve

[Steve89x]

Can't get it to idle with adjusting the idle speed or a/f screw...it's definitely running lean though...while idling with the choke on for about 5 min or so while trying to adjust the screws the header pipe started to glow..I pulled the carb again and was just wondering if you should be able to see straight threw the pilot jet like you can on the main jet?? The side holes are open I just wasn't sure about straight threw it or if its closed I couldnt find any info on this...

[Stickman400]

You should be able to see just a tiny bit of light straight through the pilot. And by tiny I mean needle tiny, it's a very small hole. Easiest way to tell if it's clogged is take a can of carb. cleaner and stick the little red spray nozzle on it and put it right up against the bottom of the jet and spray, if it comes out the end in a fan pattern then it isn't clogged.

[AtvKid4Eva]

this would be when i bought a stock 400ex carb off ebay for cheap and just throw it on there and be done with it lol.

[Steve89x]

Well I have a spare slow jet from when rejetted my other Carb so I will try that..it looks like the jet is completely clogged