400ex Doesn't idle/run...?

[wolfe 21]

Well, I pushed my '04 400 outside today to start and let it run for the first time in between 5-7 months (haven't ridden since I lost my job/insurance). I was honestly surprised the battery had enough charge to turn it over. Anyway, I hit the button and it fired, idled rough like it normally does and then died. I restarted it and it did the same thing. Also noticed it was blowing light white smoke with maybe a bit of blue tinge (no oilly residue on pipe tip, so not sure as it never ran more than maybe 20 seconds at a time). Repeated about 10 times before I got disgusted and took it back into the garage. Tried again tonight and got the same thing. It's always been hard to start/cold blooded, but it would always run on the choke until it was warmed up.
Basically, it seems like it only runs on the fuel it gets from the accelerator pump and then it sputters and dies when that runs out. Doesn't matter if choke is on or off, though it hasn't run long enough to warm up enough to know for sure. If I give it any throttle it just bogs down sputters and cuts out. Gas had stabilizer in it, 91-3 oct., stock motor and jets in carb (assuming bought used and that is what I was told and seems to fit with performance: tops about 50-55ish), stock exhaust with no arrestor/baffle, aftermarket foam filter (K&N) well oiled, stock air box, carb and tank.
Could this be a valve problem, fuel problem, what? Are there any filters to check? Any other ideas? Also, if I'm going to have to strip and clean the carb anyway (my guess, just haven't had time) what's the reasoning behind jumping the primary from 38 to 40 jet?

[CJM]

Dump out the old gas and put fresh in it. A friend of mine had the same exact problem, stabil and all and it wouldnt run it.

We put some fresh gas in, shook the atv to mix it up and bingo it fired.

Worth a shot and only a few bucks to find out.

[BlasterEaten250]

Most likely the carb just needs to be cleaned out really good, could possibly have bad gas too. Drain a little bit of the gas into a bowl and see if it looks normal or not.

[yama450yfz]

x2

[wolfe 21]

I drained the gas from the carb bowl before I pulled my carb (like I said, I figured this was the problem, so I yanked it to be cleaned) and it looked normal to me. There wasn't any debree I could see, gas was clear with a kind of yellow/gold coloring. Looked good.

Since I'm going to have the carb apart anyway, can anyone tell me why it's a good idea to increase jets from 38 to 40/42 on these bikes? Also, a good source for jets (nearest stealership is like 30 miles away and that's a long drive for a $.99 part, though I could use a new lid, some gloves and hand guards so the trip might not be a total waste)?;)

[wolfe 21]

Tore down, cleaned and reinstalled the carb last night and it seems to run much better now. Starts right up and idles OK, but it still seems to want to stumble and die while idling. May just be because I only had it running for about 5 min, but anybody have any other suggestioins?

Also, I noticed it gets hot really quick and I can smell it get warm, but it doesn't appear to burn any oil (no more smoke) or anything. It was just sitting and idling while I reinstalled the plastics and it was probably a high humidity 65-70, but I still don't think it should warm up that quick. Anybody got a suggestion as to why it's getting so hot or is this normal? For those with fans or air shrouds, do they help with low speed riding or only on faster open trails?

James.

[wolfe 21]

Well, had it out again today. Started on the first try and ran fairly good on the choke. I needed to keep giving it some throttle to keep it running, though. Anyway, after about 10 mins of riding in second gear, I stopped and it died and didn't want to restart. Finally did, but now whenever I stop and try to let it idle it just spits a little and dies. I'm wondering why it seems to run fine on the choke, but won't idle when warm and choke off. (haven't tried idling with choke on when warm)... ANYBODY got any suggestions?

I'm about to drain the tank, tear down the carb and start over again. I did notice the little plastic disc that sits over the jets (baffle plate I think from pics in manual) wasn't reinstalled last time the carb was apart. Could that be causing all my problems?

James.