42 pilot, quad doesn't idle anymore.

[f4iracer]

Hey all, i have been running a 152 main with a slip on and uni air filter.

I wanted to do the 42 pilot mod to help out with the cold start.

I've put it in and now the quad doesn't wanna idle, it will slowly begin to idle slower until it dies, sounds like it's flooding out.

should i put a 40 pilot in? or should i make an adjustment to the a/f screw?

the quad idled fine with the 38 pilot and the 152 main, but now it dies after idling for about 10 seconds.

[Honda#4]

Might have to try the 40, I know when I jetted mine the 42 was too rich off idle and would die and the 40 helped alot. Report back if you still have trouble.

[f4iracer]

40 it is, ill do that tomorow.

[f4iracer]

i've got the 40 in and it seems to start and idle a little better but it still seems rich? when i'm at low throttle, like prolly 1/8 throttle it does this lunge thing. It sounds like it's missing almost, Basically if i cruise at a low throttle it will kinda lunge and miss out.

What is causing this? do i need to adjust the air/fuel screw or something?

I've had all the pilots in, the 42 was definetly too rich and the 38 it was lunging too so that's why i thought i would need to go up, well the 40 it's still doing the lunge.

any tips? this is a pretty new quad with a lexx slip on and a uni air filter, has a 152 main jet and a 40 pilot and is lunging at low throttle.

[ukweasel]

i have an 05 with a very similar set up...lexx slip on, k&n filter.. and mine would die if i hit the throttle hard from an idle. im not sure if that is what you are talking about. i finally got mine to do right with a 40 pilot and about 1.5-2 turns out on the a/f screw. i know on the 05, and im guessing the 07 as well, it requires a special tool to adjust the screw, which has a d-shaped head. you can order them for cheap from dynojet. you have to call them to order. they are like $2-3 a piece, so i ordered 2 in case i lost another and it didn't affect shipping. hope this helps.

[ukweasel]

forgot to say that since you basically had to take the carb off each time to adjust with that bogus screw, i would leave my airbox off and play with the choke to give me an idea of if i was too rich or lean, which would tell me which way i needed to adjust.

[storms400ex]

ive got a 05, all you have to do is use a small pair of needle noses to unscrew the air screw all the way out then take a hacksaw and put a notch in it (screw), then use a screw driver to put back in then adjust it.

[f4iracer]

ok based on my symptons do you guys think i need to go in with the a/f screw or out? It's never been adjusted but i'm pretty sure that's what's causing my surging

[ukweasel]

this is what i did when mine was surging and falling on its face when hitting the throttle from an idle. i cracked the choke and the problem went away. that told me the current set up was a little lean. since it was lean, i knew i had to back out just a little on the screw. that solved my problem. hope that helps

[f4iracer]

yeah i think my problem might be different, it doesn't ever stumble or fall on it's face from giving it more throttle.

I notice the surging when you hold the throttle consistently down low, like i said. It's not when you push the throttle hard or more than about a quarter throttle.....if i do that the quad runs fine.

It happens when i hold a steady throttle at about 1/8 throttle. The quad is always plenty warm when i notice this.

For example, if i'm in 2nd gear going at 1/8 throttle my quad will kinda miss and then lunge a little. It's lets out when you are down at the low steady throttle.

Any advice guys? I need to get this resolved asap it's annoying.

[f4iracer]

uk, it says in your sig that you have a 142 pilot is that right? must be a dynojet or something eh?

[ukweasel]

yeha its a dj 142, which is a kehein 155, so i was a little off when i said we had exact same setup. im gonna go up one more size and see what happens. it runs great the way it is now, but that was the first jet i threw in just curious to see what happens. any luck with dialing yours in yet? I know on the 05's we have a fixed needle that you will have to shim with washers to adjust it. I ordered the DJ kit that came with an adjustable needle and set it to the third clip position. Maybe moving the needle up a tad may help you out?

[f4iracer]

we do have very similar setups. my airbox lid is on however. I'm doing good with the 152 main, but i need to get rid of this surging at the low throttle. I'm gonna go 1/2 more out on the a/f screw that should fix things.

[f4iracer]

ok i went out a quarter turn on the a/f screw. the surging still seems to be there. should i try to go out more on that screw to see if it fixes things?

[ukweasel]

It's worth a try. If the a/f screw doesn't fix it I would try to shim the needle just a tad. Good luck

[f4iracer]

ok, i've messed with the pilot screw to no avail.

running the 40 piliot and the 152 main. when i give it a steady throttle it still falls on it's face, it does this while in gear or while at idle.

Is it possible that i am going to have to adjust the needle with a washer?

I'm uncertain as to how to shim the needle exactly, but i've tried everything with the fuel screw and the quad still fulls when i hold a steady throttle around 1/4 throttle.

[ukweasel]

yeah i all you would need is a tiny washer. does it make a difference when you adjust the choke and determine if you're either getting too much fuel or not enough? if it's not enough then you will want to shim the needle.

[f4iracer]

thanks uk what size washer did you buy when you shimmed that needle? is there any tutorial for this? i'm kinda at a loss as to how to shim it exactly.

[ukweasel]

i bought a dynojet kit that comes with the adjustable needle, i use that on the third clip setting. to shim though you would just take the current needle out and put the washer under the circlip between the slider it sits on and then just screw the arm that holds it in place back on.

[clemsonteg]

This might be wrong but if you think that it is running to rich and thats what is causing it to fall on its face I think shimming the needle and turning the screw out would only cause it to be richer.

Taken from Jetting Help thread in the sticky section

"The preferred setting window is between 1 and 2 turns. If the engine idles at its highest RPM from 0-1 turns out this means the pilot setting is on the RICH side and a smaller pilot jet should be installed. If the engine idles at its highest RPM at over 3 turns out, this means the pilot setting is on the LEAN side and a larger pilot jet should be installed. "

When I read that it tells me that coming out on the screw adds fuel.

Also, as you can see from the picture below that by lowering the clip position, or shimming you become richer.

http://i94.photobucket.com/albums/l97/zrpilot/needle1.gif


Edit:
I forgot to add in that for me just reading about how to do it, if and when I install a larger pilot jet I would want to go directly to turn the af screw in some in order to fine tune it.

[clemsonteg]

I didn't want to edit my post a second time but I thought of something else with my other edit. If you look at UKWeasel's sig it says he is 2 turns out, with the factory setting of 2 1/4 turns out you see that he went in 1/4 turn since his mods, which include a larger pilot jet.

[ukweasel]

I have to agree with the info you've presented. That's why I was asking if it was a rich or lean problem. My problem was a lean problem, so I went up on my pilot and fine tuned the a/f screw all at the same time to eliminate my problem. If your quad is running too rich and you shim it will definitely make it richer and intensify the symptoms.

[f4iracer]

Ok, i'll leave teh needle alone and then i'll turn the af screw in 1/4 turn. I have a 40 pilot.

I noticed that the falling on it's face sympton happens much more during cold weather. It's 50 today and it's not falling on it's face. Would this also mean that during cold weather i'm a little rich and i need to turn the af screw in a bit?

[clemsonteg]

Colder weather will make you run leaner than warmer weather. The theory is that colder air is more dense, so you have more oxygen packed in the same volume vs. warmer air, which means you need more fuel in order to make it run at the same air/fuel ratio. Since a carburetor works based on air flow, not necessarily temperature, the adjustments have to be made via jet changes and/or adjusting the af screw.

Basically I would just use the powers of deduction on your machine. Turning the screw out has netted little to no results, so try turning it in to see if that helps at all.

On a side note, in a similar thread the OP is having a problem that the quad wants to bog and die if the throttle is pinned so the suggestion was to move the clip on the needle from the third to the second position essentially leaning it out a bit.

[f4iracer]

ok now i'm confused. I'm gonna get into the quad tomorrow and see if turning the a/f screw in works. But the 4 wheeler starts hard and pops and it still falls on it's face when i do the steady throttle thing so it feels like it is in fact running lean and needs more fuel. Maybe i need to try turning the a/f screw out about a half turn or more to see if that helps.

With a 40 pilot about how far out does it need to be? It's at the stock setting right now which is 2 1/2 i believe.

[f4iracer]

I can't seem to figure this out, help please!!!

I have gone in both directions with the a/f screw. it seems to run best right around 2 1/2 turns out but it will still fall on it's face.

Is my problem the needle or what? I've been in to the carburetor like 5 times and i'm about to take it in to the shop and have them get it in tuen.

This is driving me nuts!!!!

[honda400ex2003]

152, 2nd clip position on needle, 40 pilot, 2.5 turns out on the f/a would be my starting point for it if it stumbles. what do you have done now anyway? last i knew you were going to take your lid off and a bunch of other stuff. with your lid off and a new filter i would go with a 155 and the rest the same. steve

[ukweasel]

If it does better in warmer weather its getting better as its becoming richer. if you aren't getting much response from a/f screw, and you are running a 40 pilot...in that throttle range, i would say the only thing left is your needle setting...which from the sound of things needs to be adjusted upwards a clip position. but 05 and ups don't have adjustable needles, so you will need to shim it or purchase one.

[f4iracer]

have you guys ever heard of over oiling the air filter? I was told to put the air filter ina bag and let the oil get all over it.

I'm going to clean and lightly oil the stock air filter and then put it in. That way i should be able to get it in tune.

The 152 main is just fine. All i have is a slip on and uni, which i'm replacing with a stocker.

[honda400ex2003]

make sure you use air filter oil so it works correctly. you can put too much on them too. it then sucks it through and burns it. it could def make it run crappy. i just dribble oil on them around the outside then squeeze them to get the oil spread throughout. steve

[bigd's ex]

I had the same situation with mine last summer , anything over 1/4 throttle & it fell flat on it's face. I found the problem as soon as I took the top cover off of the carb. The screws that hold the arm onto the slide came loose & would'nt open the slide all the way. Something to check out. As far as the air filter being over oiled, I think that would cause a problem, especially when it's below freezing, but my question on that is, if it is that clogged up to make it stumble at a 1/4 throttle, how does it even get enough air to start? If that makes any sense. lol. Good luck!!!!!!!!!!!!

[f4iracer]

I'm getting ready to put an adjustable needle in. Both the pilot and the main are running fine, it's the needle jet that needs adjusting i believe.

So, here's my question. Will the adjustable needle on the 2nd clip be any different than my stock 2007 non adjustable needle?

Any advice on putting these needles in? I know i have to take the screw out of the lift arm and flip it aside and then i believe i have to take out the slide screws and pull the slide out.

[f4iracer]

Well i've resolved my problem. Thanks for all the hlep along the way guys.

I ended up getting and adjustable needle from dynojet, I've got the uni air filter and air box lid removed with my lexx slip on.

I'm running under 1000 feet elevation. The main jet is a 152 keihan
the pilot is a 40 keihan.
the needle is on the 3rd clip down.
the a/f screw is 3 turns out.

runs like a champ!

By the way, i tried i to run it on the 2nd clip setting and it was still falling on it's face, so my needle definetly needed to be shimmed. In this case i just got the dynojet one that has like 6 settings on it.

I've got an outerwears over the uni so it will still breath.

[ukweasel]

good for you dude, it must feel good to finally get it done!

[honda400ex2003]

congrats!! steve

[clemsonteg]

so the question is after all of that does it start easier?

[f4iracer]

It does start easier with the 40 pilot, but it's still a PITA when it's real cold.

I was having troubles though at the midrange throttle, it was running to lean and it was falling on it's face, especially in the winter. After i got the needle down on the 3rd clip setting with my setup it runs great!

I am putting the airbox lid back on however, that thing has gotta be on for the trails, i came back the other day with all kinds of **** in my air box. haha, had to clean it out...luckily i had the outerwears on but still, it's just too exposed.

my yfz450 keeps alot more debris out without the lid on, it runs great with no lid and i didn't find much stuff in the box after riding a day of trails and mud.

[clemsonteg]

Did you get to see how it runs with the airbox lid back on?

[f4iracer]

It ran fine with the lid back on. I was wondering if going to warmer weather and then also having that lid on would make me a bit rich.

It's tuned in good though!

[clemsonteg]

Originally posted by f4iracer
Well i've resolved my problem. Thanks for all the hlep along the way guys.

I ended up getting and adjustable needle from dynojet, I've got the uni air filter and air box lid removed with my lexx slip on.

I'm running under 1000 feet elevation. The main jet is a 152 keihan
the pilot is a 40 keihan.
the needle is on the 3rd clip down.
the a/f screw is 3 turns out.

runs like a champ!

By the way, i tried i to run it on the 2nd clip setting and it was still falling on it's face, so my needle definetly needed to be shimmed. In this case i just got the dynojet one that has like 6 settings on it.

I've got an outerwears over the uni so it will still breath.

When I called dynojet they told me they don't sell the dynojet needle individually. How did you get it?

[f4iracer]

that's wierd, they sent me the air fuel mixture tool and the needle. shipping was like 9 bucks or something though, it was retarded.