400ex won't start

[imjaredandstuff]

Hello all,

I recently had to put a new stock carb on my 2007 400ex. The quad is still bone stock. After I installed the carb, I put a brand new battery and brand new plug in it. It started up just fine that day when I got it all back together.

It's been sitting a couple weeks now and I went out to start and it just turns over but never starts. It's in neutral and the green light verifies that.

It started a couple times with the choke off, but it only ran for a few seconds at most before it died, due to the engine being cold. It absolutely will not start with the choke on.

Any ideas what might be wrong?

[bigbad400]

take ur plug out and see what it looks like. is it wet? sounds to me like its rich as all hell, turn your choke off and take off ur air filter and crank it over plugging the hole with ur hand, does it fire or no? either its way too rich or its way too lean. also your air filter or if you have an outerwears it could be dirty causing it to run rich. just a thought.

[Pipeless416]

sounds stupid, but is your kill switch on your starter button flipped?

[imjaredandstuff]

haha, no I made sure that it wasn't.

[krt400ex]

if it sat for a couple weeks the carb could be gummed up too.

[bigbad400]

if you let your quad sit a couple weeks and the gas went bad you need to find another place to buy gas. i have seen gas sit for a year in a machine and it didnt go bad. i would sooner think you have an air or gas problem. maybe compression but not likely.

check for a mouse nest in the intake. lol i saw that a few times.

def start by looking at your plug.

[krt400ex]

Originally posted by bigbad400
if you let your quad sit a couple weeks and the gas went bad you need to find another place to buy gas. i have seen gas sit for a year in a machine and it didnt go bad. i would sooner think you have an air or gas problem. maybe compression but not likely.

check for a mouse nest in the intake. lol i saw that a few times.

def start by looking at your plug.

nbot that it went bad. but it will evaporate and can leave a film in the carb. its possible to clog jets and stuff. not likely to happen but possible. i was trying to think of the simplest things first

[CJM]

The ethanol can cause all kinds of issues, try adding some premium gas to it and shake the tank then try and start it.

Friends had the same issue, would barely start or run, we got some new gas and voila works fine.

[imjaredandstuff]

Originally posted by CJM
The ethanol can cause all kinds of issues, try adding some premium gas to it and shake the tank then try and start it.

Friends had the same issue, would barely start or run, we got some new gas and voila works fine.

Gonna try getting new gas. The only thing that bugs me is when I put it back together about 3 weeks ago, it started up and rode just fine, I rode it around for about 30-45 minutes with zero issues. I just can't imagine the gas going bad in three weeks.

My next idea is somehow trash got in a jet and I'm gonna have to take the carb off and clean it out.