Pilot Jet???

[ginobili07]

I have a 2002 honda 400ex with a K&N air filter and just got a HMF sport series slip on and need to rejet. Should i just leave the pilot jet alone at stock and just bump up the main a couple? I do mostly trail riding and dont plan on any other big mods for my quad.

[TRXRacer1]

Most people will tell you to bump up the pilot but it's a total waste of money in most cases and simply adjusting the mix screw for more fuel will do the same thing. Bump the main and adjust the mix screw.

[ginobili07]

ok thanks

I would just buy a pilot 1 size up so you have more adjustments and stuff. I run a 42 pilot so I would say go to a 40 pilot.

[TRXRacer1]

Originally posted by FoxHondaRider
I would just buy a pilot 1 size up so you have more adjustments and stuff. I run a 42 pilot so I would say go to a 40 pilot. I'm betting you've never adjusted the mix screw have you? Going to a 40 is completely pointless.

Originally posted by TRXRacer1
I'm betting you've never adjusted the mix screw have you? Going to a 40 is completely pointless.

i'm saying this because i have seen people not being able to get rid of backfiring and having issues keeping it idling because they couldnt adjust the fuel screw anymore. It just gives you more of an adjustment.

[GPracer2500]

Originally posted by TRXRacer1
...Going to a 40 is completely pointless.

How do you figure?

[ginobili07]

I might as well just bump up the main and play with the fuel and idle screws and if that doesnt help then i can go get a 40 pilot cuz there is a honda dealership like 15 min away from me.

[coryatver]

get a 42 it will cold start so much better

[AtvMxRider]

Originally posted by GPracer2500
How do you figure?


I am waiting to hear also

[TRXRacer1]

Wow, it's amazing how many people here just swap pilots. Why is it pointless, because if you just turn the little screw Keihin built in to the carb for us then you'd know that you can get the same amount of fuel out of a 38 as you would just swapping in a 40. A 42 would make more sense if you're looking for adjustability. You can easily choke a 42 down to a 38 and open it up to more then most need. The 40 is just an unnecessary stepping stone in these carbs. No offence but I have noticed a disturbing amount of people swap pilots and don't even know where their mix screw setting is. In most cases people are just wasting money.

Originally posted by TRXRacer1
Wow, it's amazing how many people here just swap pilots. Why is it pointless, because if you just turn the little screw Keihin built in to the carb for us then you'd know that you can get the same amount of fuel out of a 38 as you would just swapping in a 40. A 42 would make more sense if you're looking for adjustability. You can easily choke a 42 down to a 38 and open it up to more then most need. The 40 is just an unnecessary stepping stone in these carbs. No offence but I have noticed a disturbing amount of people swap pilots and don't even know where their mix screw setting is. In most cases people are just wasting money.

thats why i said get a 40 pilot for more adjustability. Your not supposed to seat the screw all the way in or have it all the way out. You want it towards the middle so you have adjustments both ways when needed.

[ginobili07]

well i put in a 152 and it runs fine just gotta fine tune the fuel screw and idle and it should be good to go. Also i dont ride that much in the winter months anyway so i am not gonna worry bout a bigger pilot thanks alot for all the help!!!

[TRXRacer1]

Originally posted by FoxHondaRider
thats why i said get a 40 pilot for more adjustability. Your not supposed to seat the screw all the way in or have it all the way out. You want it towards the middle so you have adjustments both ways when needed. I need one of those smack the forehead emoticons.

You don't need to have it all the way in or out, there is a plenty of adjustability in these pilots. The 40 is flat out pointless if you can turn a screw driver. Changing pilots when you don't need to isn't a performance enhancement, it's just a waste of money.

[TRXRacer1]

Originally posted by ginobili07
well i put in a 152 and it runs fine just gotta fine tune the fuel screw and idle and it should be good to go. Also i dont ride that much in the winter months anyway so i am not gonna worry bout a bigger pilot thanks alot for all the help!!! Try 3 turns out on the mix screw. It got me through the WI winters just fine (until I switched to E85).... ;)

[ginobili07]

OK, it jsut wont idle i drove it and it rides thru the gears fine and sounds good too but it just wont idle at all and it was shooting some flames out of the tail pipe.

[GPracer2500]

Originally posted by TRXRacer1
I need one of those smack the forehead emoticons.

You don't need to have it all the way in or out, there is a plenty of adjustability in these pilots. The 40 is flat out pointless if you can turn a screw driver. Changing pilots when you don't need to isn't a performance enhancement, it's just a waste of money.

Alrighty then. I've got no problems using a 40 when it's called for. The fuel screw doesn't provide an infinite adjustment range. If the fuel screw doesn't provide the rich-side adjustment needed with the stock pilot then there's nothing at all wrong with using a 40. I understand what your saying. I even wrote a "How To" post for adjusting fuel screws. But to say that using a 40 pilot is "completely pointless" is over the top. Sometimes it's needed, sometimes it isn't. Like all things that have to do with jetting choices, it depends on the circumstances.

If you had said, "Adjust your fuel screw first. That's what it's there for. If richening the pilot circuit by that means is not adequate, THEN AND ONLY THEN is a pilot jet change warranted", then fine--I'm with ya. But saying a bigger pilot is pointless is kind of a sweeping statement IMO.

[TRXRacer1]

Never said a bigger pilot is pointless, I said going to a 40 is. If you need that much more then a 38 has to offer and want adjustability then just go for the 42 and back it off. I'm at a 52 for my E85 so I know what they are used for and that you do need to step up in some cases. What pushed my mouse button was the suggestion of getting a 40 without any mention of mix setting. There are a lot of pep's around here that swap pilots when they don't need to. If you just swap in a 40 and don't touch your mix screw...... and it was exactly what you needed...... then you needed a screw driver not $6-7 less in your wallet.

[GPracer2500]

Maybe I misunderstood your intent.

I guess what pushed my mouse button was I felt you where getting on just a little bit of a high horse--as though everyone but you was an idiot for not realizing that "...a 40 is completely pointless..." Which, BTW, I still don't agree with. Why go from approximately the richest fuel screw setting with a 38 to approximately the leanest fuel screw setting with a 42 when there is a perfectly good 40 available? If a 40 gets you a properly jetted pilot circuit with the fuel screw right in the middle of its adjustment range, why skip it?

peace

[TRXRacer1]

Originally posted by GPracer2500
Why go from approximately the richest fuel screw setting with a 38 to approximately the leanest fuel screw setting with a 42 when there is a perfectly good 40 available? You aren't anywhere near the leanest setting on a 42 to get an average 40 flow, you can choke it down a lot further then that. These jets are very close in flow. I know there's a few guys around here that know how to adjust a mix screw but there aren't many. People are just too damn quick to telling people to buy pilot jets when most don't even need them. I'm on a bit of a horse here but it's the right one.

[zrpilot]

I gotta side with GPracer2500 on this one!

IMO, when doing jetting of any kind without a lamba sensor (like most of us here!!), and considering a jet change, do it in logical steps.

I would not go from a 160 main to a 180, without trying something in between.

Besides it gives the owner/mechanic an opportunity to learn about their carb and motor.

AND they only cost about $5, not like that is going to break the bank!!!!!

[TRXRacer1]

Originally posted by zrpilot
I gotta side with GPracer2500 on this one!

IMO, when doing jetting of any kind without a lamba sensor (like most of us here!!), and considering a jet change, do it in logical steps.

I would not go from a 160 main to a 180, without trying something in between.

Besides it gives the owner/mechanic an opportunity to learn about their carb and motor.

AND they only cost about $5, not like that is going to break the bank!!!!! Nobody was talking about the main...........:rolleyes:

[zrpilot]

Originally posted by TRXRacer1
Nobody was talking about the main...........:rolleyes:

I'm using it as an example.

[TRXRacer1]

Originally posted by zrpilot
I'm using it as an example. But the example doesn't work. The pilot has a range of adjustability where the main doesn't. If you think there is something to be learned from from swapping parts that don't always need to be then maybe we look at education a little differently.

[zrpilot]

I agree about swapping parts..... I also agree with the adjust ability of a pilot circuit.

My points are:

1)We are talking about $5 pilot jets.

2) As GPracer25 stated: "If a 40 gets you a properly jetted pilot circuit with the fuel screw right in the middle of its adjustment range, why skip it?"

IMO most people on the 400EX forum are not jetting experts (perhaps you are??). Answer me this question: Is it all that bad making recommendations that progress jetting changes slowly, logically, using INEXPENSIVE parts?
And as a plus the person doing it can get some experience working on their carburetors.

[TRXRacer1]

Originally posted by zrpilot
Answer me this question: Is it all that bad making recommendations that progress jetting changes slowly, logically, using INEXPENSIVE parts?
Yes it is bad, that's what I'm saying. To teach someone to swap parts in they don't need whether inexpensive or not you are not teaching them the correct way to do it. A lot of the readers here are still in high school and that pilot jet is 1-2 hours of their life wasted working at a part time job after taxes. Spending $5-7 dollars on a pilot jet when you don't need one and not understanding how your carb works in the process is just sad. Some dude could be serving up ice cream cones for over an hour just to pay for something they wouldn't have needed if they had the knowledge to tune a carb and turn the handle of a screw driver. I'm not an expert but waste is still waste.

[zrpilot]

Originally posted by TRXRacer1
Yes it is bad, that's what I'm saying. To teach someone to swap parts in they don't need whether inexpensive or not you are not teaching them the correct way to do it. A lot of the readers here are still in high school and that pilot jet is 1-2 hours of their life wasted working at a part time job after taxes. Spending $5-7 dollars on a pilot jet when you don't need one and not understanding how your carb works in the process is just sad. Some dude could be serving up ice cream cones for over an hour just to pay for something they wouldn't have needed if they had the knowledge to tune a carb and turn the handle of a screw driver. I'm not an expert but waste is still waste.

LOL that is funny!!!! I repectfully agree that we dis-agree.

I'm going for an ice cream cone.... wanna join me!!! LOL.

Originally posted by zrpilot
LOL that is funny!!!! I repectfully agree that we dis-agree.

I'm going for an ice cream cone.... wanna join me!!! LOL.

I'm in, ice cream is goooood! lol

[dsm_racing]

Could any of you more knowledgeable guys please take a look at my thread?

http://www.exriders.com/vbb/showthread.php?s=&threadid=350832

[dariusld]

Iv'e answered many threads stating " you don't need a new pilot jet" only to be looked upon as an idiot because the consensus thinks you do.

[TRXRacer1]

Originally posted by zrpilot
I think you do... but TRXRacer1 and I have a dis-agreement, which is OK... Yup, you think as long as it's cheap there's no need to learn how the carb fully works and buying unnecessary parts is justifiable.

I think people should just learn how they work and pick up a screw driver.


Originally posted by dariusld
Iv'e answered many threads stating " you don't need a new pilot jet" only to be looked upon as an idiot because the consensus thinks you do.

Amen! I don't know why but that is indeed the consensus around here.

[zrpilot]

Originally posted by TRXRacer1
Yup, you think as long as it's cheap there's no need to learn how the carb fully works and buying unnecessary parts is justifiable.


That is NOT what I think. I think you DO learn about your carb by changing pilots and then tweaking the idle adjustment and discovering how the bike runs, better or worse.

[BigBore24]

that is rediculous implying zrpilot doesnt know how the carb works. he has answered about 75% of the carb questions on this forum that i have read. it seems as though he tried to put a respectful end to it by saying its ok to disagree. seems like it would be logical to agree to disagree

[NXGHOST]

I recently put a Full trinity exhaust, UNI filter and drilled the Airbox. I went from a 148 main/38 pilot to a 158 main/42 pilot.

At idle after a few minutes it starts running rough and the plug gest black. I can close the pilot screw all the way in and it still idles rich. Should it not stall or run rough with it all the way in? Was a 42 Pilot too big?

Originally posted by zrpilot
That is NOT what I think. I think you DO learn about your carb by changing pilots and then tweaking the idle adjustment and discovering how the bike runs, better or worse.

I fully agree!

[zrpilot]

Originally posted by NXGHOST
I recently put a Full trinity exhaust, UNI filter and drilled the Airbox. I went from a 148 main/38 pilot to a 158 main/42 pilot.

At idle after a few minutes it starts running rough and the plug gest black. I can close the pilot screw all the way in and it still idles rich. Should it not stall or run rough with it all the way in? Was a 42 Pilot too big?

There is something else going on.. Could the float level or float needle be bad?

[NXGHOST]

Originally posted by zrpilot
There is something else going on.. Could the float level or float needle be bad?

I dont think there are any mechanical poroblems as the 400ex is like new, under 10 hours on it. What should happen with the pilot all the way in? I just ordered a Motion Pilot tool so I can access the screw better and make quicker changes, I am not even sure I had it in 100% because it is a MOFO to get to!

[zrpilot]

The jetting is close enough to run. When you re-jetted did you take the carb off? I'll bet something like the plash shield or the float level or the float needle is not right....

Double check the installation of the carb and all the needed accessories.