why does my 400 stall when i let off throttle?

[moddedblaster20]

hey guys, some times when im riding and im on the throttle then let off the quad will idle down and stall, does it more so when its cold. but yet it can sit and hold a good idle while parked. any help would be great. its an 02 400 by the way. i was guessing a jetting problem?

[slightlybent47]

I wouldn’t jump to the jets right off. Did it run fine before? If so check and or change the gas if its old. Check your tank for trash. Take the fuel line of the carb and look down the hole and there should be a screen, clean it. Clean the carb real good.

[moddedblaster20]

well i just got it before chirstmas so i have only ridden it i nthe cold, there was one warm day it seemed to run better but i dont know maybe it was just my imagination haha. i will try taking the fuel line off. thanks!

[riotact]

First I would check the throttle cable and make sure the lock nuts didnt back off.That may be your problem.

[JOHNDOE83]

I dont think the throttle cable has anything to do with it....it has to be jetting or its clogged in the pilot jet. if the idle is set to low it will die at speed when you let off the gas also...the pilot jet is used for idling and up to 1/8 throttle. so if its clogged or to small it will pop and die.

[riotact]

Originally posted by JOHNDOE83
I dont think the throttle cable has anything to do with it....it has to be jetting or its clogged in the pilot jet. if the idle is set to low it will die at speed when you let off the gas also...the pilot jet is used for idling and up to 1/8 throttle. so if its clogged or to small it will pop and die.

If the idle screw on the carb is backed out to far and the lock nuts
on the cable have backed off too it will do that.I've seen some people adjust their idle with the cable and lock nuts at the handle bars because of not having a screw driver with them so it is very possable.It would be like how you adjust the clutch at the bars.Just another option for him to check out.

[moddedblaster20]

you talking about the lock nuts on the bars for the throttle cable?

[steve181]

my moms 02 400 is the same way
i cant get the damn thing to hold an idle cold lol

[cheater13]

my mojave 250 used to do this when it was cold out. i just kicked it and let it sit a while to warm up and it was fine then

[moddedblaster20]

it holds an idle just when i let off thottle when riding it will stall sometimes lol

[riotact]

Originally posted by moddedblaster20
you talking about the lock nuts on the bars for the throttle cable?

Yes

[JOHNDOE83]

the adjustments on the cable takes up the play in the cable, not the idle adjustment. if your using your cable for adjusting the idle somethings not right.

[tywebb3]

My '05 does the exact same thing but it only happens every once in a while...not consistently. I will have to try bumping up the idle a little to see if it goes away.

Since I bought the bike used this past fall I have completely cleaned the carb (completely disassembled, dipped, all ports cleaned out, etc.) 42 pilot installed, needle clip moved down one notch (2nd from bottom), air/fuel screw 2 1/4 turns out, 158 main installed w/Fat Boy4 exhaust, fuel changed out, and the valves have been adjusted. This has helped to make the problem less frequent but it does still happen every once in a while? I haven't had the chance to ride it in warm weather yet so it will be interesting to see what it does then.

[moddedblaster20]

man thats the same with me! cept i havent done any thign with jets

[GMC400ex]

could be slow jet..mine done samething when i bought it..the guy never rode it or anything had old gas in it and the slow jet was clogged up..but it did it in the middle of summer..id say it being cold doesnt really help but still might want to check out your slow jet..not saying that is def the solution..hope it works out

[moddedblaster20]

i mean its still ridable now, just try and stay on the gas a little bit. will see how it is in the warmer months. thanks everybody

[400ex=awesome]

mine did that too and then i seen tht the choke was on

[moddedblaster20]

i turned up the idle just a bit so when i let off thorttle it doesnt idle down that low. seemed to help

[tywebb3]

I did the same this past weekend. I turned mine up 1/2 turn and it seemed to help. I didn't get to do a lot of riding because of the blizzard but it seemed better during my short ride. Maybe these thing just like a little higher idle?

[moddedblaster20]

aw man u missed out. im in Nj and got hit with the snow storm and rode all day Saturday haha. of course i had to wait til they plowed the roads first lol

[tywebb3]

We got close to 30" of snow so most of my time was spent clearing the driveway and playing with my kids. I did get a little ride in on Sunday but didn't think about turning the idle up until near the end of the ride after it stalled out on me a couple times. Once I made the adjustment it didn't seem like it ever got close to shutting down.

The great news (sarcasm) is the weather man said we have another storm on the way for tomorrow evening into Wednesday that will dump another 1-2 feet on us. MAKE IT STOP!!!!!

[slightlybent47]

That sounds great, it’s nice when it’s that simple. Sorry can’t help you with the snow.

[moddedblaster20]

i cant wait for the snow, just so i can ride my quad on the street haha