My last jetting??

[YBRIK]

07 400EX Only mod pro circuit slip on, lid on, might buy K&N filter but thats it. Im from Indiana (about 650'ASL)OK i jetted it last week(42 pilot ,158 main,removed the choke and fuel screw is 2 1/2 turns out)starts fine(cold),plug is mid to light brn runs great but when its idling it has a slight miss but it does'nt die. rev it up and it idles norm for a few seconds than back to choppy idle? when i rev it up it has a puff of white smoke at decel (maybe cold weather?)Any thaughts or suggestions.Is a 42 pilot too rich?or will the 42 pilot be to rich in the summer? seems like most people put in a 42 pilot and leave it year round..The main jet is no problem i have a 152,155,158,and160 and i can swap them around winter/summer i just dont want to mess with the pilot 1 or 2 times a year.Thanks!!

[YBRIK]

O and i did plug that hole when i removed the choke..

[GPracer2500]

42 and 2 1/2 turns out sound awfully rich. This should help: http://www.exriders.com/vbb/showthread.php?s=&threadid=229923

[hornetgod13]

If you have the right sized pilot jet installed you should'nt have to swap it with seasonal changes. You may have to adjust the fuel screw.

I had a similar problem. I bumped up my idle a little bit and the miss or stumble went away. It only happened to me when it was cold.

Try this......Pull your air box lid off and fire it up. If that makes the misfire go away than you are too rich on the pilot jet. You could step it down to a 40K or screw in the fuel screw a turn or so and see if that solves it.

I have a 158K installed with a Hi-Flow EHS racing lid, UNI filter, and HMF Slip on. I'm 250 to 500 ASL and temp is 50-80 degrees. You Main Jet might be rich. If you pulled your lid off and ran it I bet you could feel a huge improvement.

Your whole set up sounds rich. If the quad runs better with the air box lid off than you need to come down on your jet sizes or leave the lid off.

[YBRIK]

I did pull the lid off and it didnt change the idle

[hornetgod13]

I kept my choke installed but, haven't needed it since installing a bigger Pilot jet.
Try the lid idea first or adjusting your fuel screw "IN" before going down to a 40K jet.

[YBRIK]

if i do go back down to a 40 pilot will i have cold start issues again???( i dont want that w/no choke) i bet a 40 pilot and a 155 main would be about right all year round..w/fuel screw adjustment for summer/winter what do u thank?

[hornetgod13]

It sounds like your pilot is rich. If not fixed, this problem will only get worse in the summer when the are is thinner. For now remove the lid or turn your fuel screw in a turn or so and see how that effects your idle and decel. You might also think about air box mod like removing it entirely and installing Outerwears to the filter, drilling holes in the lid or using a EHS Racing Lid.

40K Pilot and 155K Main and adjusting your fuel screw in or out for seasonal changes sounds real close with the mods you have.

[YBRIK]

fuel screw stock is 2 1/2 turns out how far in or out can i safely adjust it?

[hornetgod13]

You can turn it all the way in but, If you turn it all the way in and it doesn't kill the motor than your 42 pilot is too big. It should kill the motor if it's all the way in.

[YBRIK]

Im kinda scared to run w/o airbox lid because i do ride in all conditions.when i ordered my jets i ordered 40 and 42 pilots and 155,158,and160 mains.so i have plenty of jets.do u think it will still start (cold) w/40 pilot? thanks!

[YBRIK]

i will try to screw it all the way in and see if it kills it (and thanks for your help)

[YBRIK]

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[GPracer2500]

Originally posted by YBRIK
....do u think it will still start (cold) w/40 pilot? thanks!

Couldn't say for sure one way or the other. But a few quick stabs of the throttle before you hit the starter will prime the engine. This can help a lot if you have issues starting in the cold with no choke. Quick stabs of the throttle activates the accelerator pump. This shoots a stream of raw fuel straight into the engine. The AP can basically double as an enrichener device for cold starts.

[YBRIK]

thanks!this jetting stuff gets old after awhile but i dont want to tear it up tho!

[Honda#4]

try a 40 pilot and a 155 main and put your needle on the 4 slot from the top and take the lid off. If it's missing at idle then your needle has to go up one slot.

[YBRIK]

07 has no adj needle. I thaught needle effects midrange and the midrange is fine.i dont really want to run w/o airbox lid i ride in all conditions.Im just going to put in a155 main,40 pilot,and k&n filter run it sunday@badlands and see how it go's. hopefully it'll start cold w/no choke. (if so i thinnk i'll be set)a few quick jabs to the throttle does work alot better than just pumping the gas a few times.

[hornetgod13]

The needle does control the mid throttle range. The 2005 and newer carbs do not have an adjustable needle. You can buy a needle for an older 400EX or buy a DynoJet kit and the adjustable needle is included.

[Honda#4]

I forgot that little detail. MY BAD

[kilgoja]

i didn't know that...i've been thinking of adding a slip on pipe...i have an 07......so i guess u are refering to the needle with the clip positions on it.....so if i add a pipe am i going to need an adjustable needle or will it be ok with the stock needle?

[hornetgod13]

Old thread.
I thought this one died 5 months ago.

Just stick with the stock needle for now.