[Instructions on changing a Honda 400EX Pilot Jet. (Cures Cold Starting Blues)] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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Instructions on changing a Honda 400EX Pilot Jet. (Cures Cold Starting Blues)
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Posted by: Zingnut

Turn your gas valve to off
Start the quad and let it idle till it dies from lack of gas
Remove the rear seat and plastic
Remove the two 5mm allen head bolts from the front plastic
Remove the four 10mm bolts from under front fenders
Pull off gas cap
With a flathead scewdriver pop the black push locks up and out Pull off the tank cover
Pull the front plastic forward and out of the way of the gas tank
Remove the two 10mm tank bolts and two rubber straps on either side
Remove gas line from gas valve
Pull off tank
Remove 10mm bolt to air filter box and loosen phillips headed screw clamp on carb from airbox
Remove push lock from clear plastic intake tube
Remove clear catch container from clutch side of black air filter tube
Pull off the air filter and clear intake tube
Loosen phillips headed clamp on motor side of carb
Remove carb (watch for gas to drain when flipping carb over)
Remove four phillips head screws from bottom of carb (pic 1)
Remove plastic ring from main jets (pic 2)
Gently remove Pilot Jet from carb (pic #3)
Gently screw in new #42 Pilot jet (do not over tighten)
Then go through these instructions in reverse to put your bike back together.

The last Pic is of the stock jet and the new jet.

Hope this is handy for everyone without the manuals!!!

Posted by: Zingnut

Pic #1

Posted by: Zingnut

Pic #2

Posted by: Zingnut

Pic #3

Posted by: Zingnut

Pilot Jet Pic

Posted by: Gecko

Great post!

Maybe this should be in the FAQ section for all of the new folks.

Thanks again!

Posted by: cbrown400ex

Great post. The only thing I did different is that I didn't take the gas tank off. Just the straps. Then I lifted it and slid the throttle cable out from under it. Might save a little time.

Posted by: MOFO

Yep, I say this puppy ought to be in the FAQ as well. Nice post Zingnut! Very detailed....

Eric

Posted by: extremejrowe

so wuld overtightening it just strip out the pilot jet threads?

Posted by: 400exrules

i would like to HIGHLY recommend going to home depot and getting some stainless bolts to replace the 4 crappy brass ones that hold the bottom of the carb on in pic #1. the heads of the brass ones strip very easily

Posted by: GPracer2500

I don't remove the carburetor. I just loosen it enough to turn it to the side just enough to allow access to the float bowl screws with a small screw driver. No need to remove all that plastic.

The picture of the two pilot jets above: the one on the left is a series 26, the right one is a series 21. The 400EX carb actually takes a series 26 but a series 21 will work.

I'm with 400exrules about the float bowl screws. I actually replace nearly every screw on the carb with allen head bolts. That way it's easier to get to them with a ball-end allen wrench. This really helps when changing the needle. You have to be careful about overtightening though. They make those philips head screws soft on purpose. The idea is that the screw head will strip before you can damage the much more costly carb body.

Posted by: Chris 75

cant you access the pilot by taking the bowls drain plug out? it is right next to the main on all my keihn carbs I ve never taken the bowl off to access the pilot. Drain plug is a 17mm that would save you from those 4 screws that are so soft. And with a small enough screwdriver you might not even have to cock the carb I dont know what the spacing is on a 400 though between bottom end and carb.

Posted by: Crath

if im switching from one aftermarket exhaust to another, is this all i need to change?

Posted by: 400eXr1d3rZ

No, if you already have a 42 pilot jet and already a 155 or so main you wont need to change anything at all, depending on what the situation is. If you going from slip on to full, you need to go up a jet, ex: 155 to 160.

Posted by: AbnMP13

This is awesome, now someone just give me enuf patience to wait for the new needle and HMF exhaust to come in!

Posted by: AbnMP13

The new needle came with a brass in color, close to 1.5 inch long fitting of some type. Any clue as to what it is?

I'm swapping needle for needle so I assume it's not needed.

Posted by: casey_lamm

Im about to do this for the 1st time. Where did the pictures go?

Is there this list somewhere that the pictures work?

My riding Alt is about 1000ft asl to a max of 2000ft. Typically 1400ft or less

Just trying to figure out what to get so I can get started.

Also please advise

have gotten alot of help from others as to what to do with my stock 07 400 ex.

1st mods to be installed...I decided to go ahead and do it myself after some gentle poking from other members.

K&N Stage 1 Power kit with Dynojet kit.

HMF slipon.

Thats it. I want to jet it after installed those 2 mods.

What do you think would be a good size to start with?

Also, should I do anything to the idle setting and stuff like that.

Give that this bike is new and im adding that stuff...walk me through what I should do and I how I should tackle this project.

I have some pretty good diagrams and pictures of how to do the jetting...but want some people who have done it to talk me through it so to speak.

Thanks in advance!