Bogging in the top end.

[Zakradu398]

My 400 recently started to kind of stumble if i hold it wide open. Right before rev limiter it will pop and lose power/ sound like its flooding almost. My jetting is good and carb is clean. Whats the deal?

[HondaRacing83]

Wow, my first guess would be carb. I don't think itd be blowing, youd think thatd go all at once. is there any kind of sound in the motor like a knocking or ticking?

[Pipeless416]

you said your jetting is good, but what is it? what's your main? temps dropping could cause a rich condition and you probably need to lower the main a bit.

[duneslider]

Pipeless, not to be a jerk but you have jetting backwards. Winter=denser air which will mean a lean condition so you need to jet up, go bigger jet size.

Bogging typically is associated with a rich condition but if there is popping I would suspect a lean condition.

We need more info. What is the jetting? Mods? Temps? Some areas use a reformulated winter gas that is crappy. How do you know the carve is clean? Just cleaned it? No airleaks in the intake passage?

[Zakradu398]

1200 ft. Just a yosh slip on. I got the lid on now. 155 main 42 pilot clip is I believe richened one clip from stock. Not sure what clip number it is.

Edit: temp is from 20-45 now

[Pipeless416]

Originally posted by duneslider
Pipeless, not to be a jerk but you have jetting backwards. Winter=denser air which will mean a lean condition so you need to jet up, go bigger jet size.

Bogging typically is associated with a rich condition but if there is popping I would suspect a lean condition.

We need more info. What is the jetting? Mods? Temps? Some areas use a reformulated winter gas that is crappy. How do you know the carve is clean? Just cleaned it? No airleaks in the intake passage?

haha must have been too late in the night for me to be posting. funny because i have understood the jetting up for winter concept for as long as i can remember..:huh

not to mention i just had to do this myself last week lol.

[powerbomb400]

Winter time means more O2 in the air. Its summertime when the conditions get to the lean times. There is less O2 in the summer. That's why you make more horsepower in the winter than the summer.

[duneslider]

I guess that is a relative statement too, if its too cold you will lose power. There is an optimal temperature and anything above or below causes issues to combustion.

Let's just say we need to jet according to temperature, humidity, and elevation. All of those change the combustion formula. Then we could get into fuel mixtures and how that can affect jetting but we don't really want to do that.

[Zakradu398]

More oxygen in winter= lean
Less in summer = rich.

Now why am I bogging?

[duneslider]

You can still get a bog when lean. You mentioned popping, that generally is a sign of a lean condition.

We need more info, that I asked for above.

[Zakradu398]

It's above pipeless' response bro

[duneslider]

Did you have lid off before and you just put it back on?

[Zakradu398]

Ya. When it was warm out I had it off. Got cold I put it on.

[duneslider]

Try pulling it off and seeing what it does. See if it gets better or worse. What's your plate color like?

[JOHNDOE83]

Well, depending on your definition of bogging it could mean anything.

But bogging is a lean condition.

If its to rich on the top end it will sound like a rev limiter kicking in but have more of a stutter sound.

If its to lean it will also sound like a rev limiter but will backfire or pop.

Bogging generally happens in the low and mid range and is a lean condition.

Maybe you should check the needle and try it on a 1 notch richer and see if the bog gets better, it is winter time, might have gone a tad on the lean side.

It is winter time, just a thought.

[duneslider]

Also, when did you adjust the needle? Did you just recently change the needle?

[Zakradu398]

Needle was changed prior to cold weather. The bog is more like an early rev limiter kicking in. It will pop when it's studderinng and I suddenly let off the throttle. Now that I think about it, it did this one day it went up to 65 where my jetting was perfect at until this issue

[dxcody]

have you looked at your plug?

It will be pretty obvious which way your motor is running by the way your plug looks.

Valves in spec?
Timing in Spec?

Try replacing the plug, see if it has any effect on it.

Air filter clean?

A dirty air filter can easily cause bogging in the top end,

More throttle = more air being sucked into the carb and if its not getting enough air to mix with that gas then it will bog and run really rich.

let it warm up, take it out and go easy in 2nd gear, then nail the throttle to WOT.

Tells us what happens.

[Zakradu398]

Valves in spec , air filter clean.. I'll take a go pro vid for y'all to see what's happening

[dxcody]

hmmm.. i was hoping for your sake it would be something easily overlooked like the airfilter or somerthing

[Zakradu398]

You and me both.. I'll pull the carb, clean it again I guess, richen the needle and take a vid. Probably tomorrow.

[Zakradu398]

What plug should I get also?

[Pipeless416]

NGK DPR8Z

[Zakradu398]

thanks brah

[Zakradu398]

uploading a vid now..

[Zakradu398]

Finally got a vid to show what its doing,

http://www.youtube.com/watch?v=-h8ja82vRPw&feature=youtu.be

[duneslider]

What color is the plug after the run?

[Zakradu398]

I will let you know in a few

[Zakradu398]

This will sound very dumb but what size socket do I need for the spark plug. I can't remember what I used before and I ant find one that fits...

[CJM]

18mm thin wall or you need the one that came with the quad.

[Zakradu398]

Tankks

[Zakradu398]

Heres the plug, gap was a little tight. Took apart carb and made sure it was clean but it was good. The a/f screw was at like 5 turns out so I reset it to 2.5 turns out. I took it for a spin and it acted up for like 5 mins then was good after that so I'm not sure if its good now or what.

I also checked my compression for the hell of it and it was at 117 which is great.

Plug doesn't look too too bad, defintaley not the best though..

[hondamikey7o2]

You know if your still having the bogging problems it could be in your ignition. If the electrical system is cutting out for a second it would sound and feel like the motor was bogging out due to lack of fuel. I could be a loose wire I would look in the ignition before looking for a problem with spark.

[Zakradu398]

It would do it at all rpms though if that were the case..

[hondamikey7o2]

Well I was thinking the high rpm and vibration could cause a wire to loose conection. Your carb is jetted right and its getting fule then I would think that ignition would be the next stop on your check list.

[TheAwesomehonda]

[QUOTE]Originally posted by Zakradu398
1200 ft. Just a yosh slip on. I got the lid on now. 155 main 42 pilot clip is I believe richened one clip from stock. Not sure what clip number it is.

Edit: temp is from 20-45 now [/QUOTE What clip r u talking about anyhow a 400ex carb don't have a adjustable needle(my 05 doesn't).

[Stickman400]

Originally posted by TheAwesomehonda
[QUOTE]Originally posted by Zakradu398
1200 ft. Just a yosh slip on. I got the lid on now. 155 main 42 pilot clip is I believe richened one clip from stock. Not sure what clip number it is.

Edit: temp is from 20-45 now [/QUOTE What clip r u talking about anyhow a 400ex carb don't have a adjustable needle(my 05 doesn't). Most people on here buy a rebuild kit (which has an adjustable needle) or an adjustable needle from a '99-'04.

[Zakradu398]

Mine is an 04. Adjustable.

What should i check with the electrical

[TheAwesomehonda]

Originally posted by Zakradu398
Mine is an 04. Adjustable.

What should i check with the electrical I had to idea of that so how many notches are there on the needle for the clip?

[CJM]

5 notches, count them from the top-the flat end. Most everyone will need it to be 3rd notch down.

Zak-thats WAY to rich your plugs black and all carbon. Id swap to a 150 or 152 and see what happens or take off your airbox lid.

[Zakradu398]

I have a 155 in it, I'll switch back in the 152.5

[Zakradu398]

I put in a 152.5 and it's better. Just need to put the clip back on the 3rd notch and I should be good.

[CJM]

Sounds good. Check your plug again when you got it all set up.

[Zakradu398]

Will do, thanks for the help bro