Would like Pilot answer plz

[Ryan'07400ex]

Ok Im making this thread hoping someone will help. I can't get an answer in the " Jetting Help" thread. sry to make another jetting thread

I recently put a 42 pilot jet in but didn't screw it in all the way thinking that I saw to leave it a half turn out. Now it stumbles when i quickly throttle it. Is it because I need to tighten that pilot or do i need to change the air/fuel thingy. haha
Thanks

[tri5ron]

the jet must be seated all the way, and yes you need to adjust the A/F mixture.

[Ryan'07400ex]

Originally posted by tri5ron
the jet must be seated all the way, and yes you need to adjust the A/F mixture.

k thanks now i just have to figue out how to adjust it and ill be ready haha

[rocky_mtn_honda]

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should get you in the ballpark :)

[Ryan'07400ex]

Thanks but i dont think i have those tools so I may have to take it to my local dealer... and I actually thought I would save money doing it myself. :rolleyes:

[rocky_mtn_honda]

seriously, if you can take the plastics and gas tank off to get at the carb...then all you should need from there is a flat head screwdriver to adjust the pilot screw
other than that a phillips #1 for the float bowl
a 17 mm wrench or socket for the float bowl drain/main jet access hole
the mainjet is a 6mm socket
and the pilot is just removed with a thin flathead screwdriver...but yea, save yourself some dough and adjust that pilot screw with a flathead screwdriver...no biggie, and the throttle stop screw/fine idle adjuster is turned by finger, just twist it

[Ryan'07400ex]

Well u see I've already rejetted but i didn't tighten the pilot jet and I didn't do anything to the pilot screw.
I thought I would need a pilot screw tool and a tachometer or whatever

[rocky_mtn_honda]

it's not a big deal, just take the float bowl back off and make sure the pilot JET is securely seated...may as well check your main jet to make sure its tight as well...throw the float bowl back on, and use a flathead screwdriver to adjust the pilot SCREW (totally different from the "pilot JET") per the manuals direction in "pilot screw adjustment"...then fine tune it and your done...you dont need a tach. if you have been around bikes and know what a healthy idle sounds like...shouldnt bluurp when you punch it, and it shouldnt hang when returning to idle
i have faith in ya...you know, a lot of stealerships charge up to $175 to tune a carb...:eek2: rediculous

[Ryan'07400ex]

Originally posted by rocky_mtn_honda
it's not a big deal, just take the float bowl back off and make sure the pilot JET is securely seated...may as well check your main jet to make sure its tight as well...throw the float bowl back on, and use a flathead screwdriver to adjust the pilot SCREW (totally different from the "pilot JET") per the manuals direction in "pilot screw adjustment"...then fine tune it and your done...you dont need a tach. if you have been around bikes and know what a healthy idle sounds like...shouldnt bluurp when you punch it, and it shouldnt hang when returning to idle
i have faith in ya...you know, a lot of stealerships charge up to $175 to tune a carb...:eek2: rediculous

Ight Thanks so much man you're really helping me out. I believe I'll be able to fix it now to.

[rocky_mtn_honda]

np...keep me posted;)

[Ryan'07400ex]

Originally posted by rocky_mtn_honda
np...keep me posted;)

welp pulled it apart only needed another rotation to be "tight". I was hoping this would make the bog go away... it didn't. so i guess ill go buy a pilot screw tool cause nothing I got now works.
I guess my jets are the right number, to high wouldn't make it almost stall would it? (152 main 42 pilot)

[rocky_mtn_honda]

almost sounds to me like your trying to jet a cold machine...let it warm up a little before you try hittin the throttle...if its cold, it will bog yes, or its choking on fuel...pull the plug and see if its getting wet...adjust the pilot screw with a screwdriver...im not even sure if you can buy that pilot screw tool...its a genuine honda tool...u really dont need it, swear!

[tri5ron]

a .99 cent stubby screwdriver will work just fine.

[Ryan'07400ex]

Originally posted by tri5ron
a .99 cent stubby screwdriver will work just fine.

Idk how the heck you all use a screwdriver in between all that stuff when its so hot. I couldn't move it when it was off much less with the carb back on.

I have never moved the pilot screw so shouldn't it be at 2 1/4 like its supposed to be.

I don't know why everyone says jetting is so easy... I thought you unscrewed the old, then screwed in the new but aparently not. I wish I woulda never changed the jets.

Just a hope but do you thing having that rubber piece on the accelerator pump thing turned wrong would be doing this cause maybe when I hit the throttle the accelerator pump isn't working right.

BTW my spark plug had a bit of white on it but my plug wasnt screwed all the way in :confused: .... it idles good just wants to stall when i somewhat cramm the throttle

[rocky_mtn_honda]

well it sounds like your A/F ratio is a bit lean...turn it off and let it cool between adjustments if that helps, and as for your pilot screw, if you werent able to move it with the carb off, then somethings wrong...it shouldnt be too tight to turn. turn the pilot screw all the way in to where it "lightly seats", then back it out to where it should be stock, then go from there
you'll get it mastered, i mean afterall, you are saving yourself $175 +/-

[bigbad400]

spin the bottom of the carb toward the fuel petcock and you should be able to reach with any driver, i do mine with a six inch skrew driver. hell ive done it with my thumbnail befor because on the trail i didnt have a driver with me.

[Ryan'07400ex]

Originally posted by rocky_mtn_honda
well it sounds like your A/F ratio is a bit lean...turn it off and let it cool between adjustments if that helps, and as for your pilot screw, if you werent able to move it with the carb off, then somethings wrong...it shouldnt be too tight to turn. turn the pilot screw all the way in to where it "lightly seats", then back it out to where it should be stock, then go from there
you'll get it mastered, i mean afterall, you are saving yourself $175 +/-

OK so you change ur A/F ratio with the pilot screw right? I'm not clear on that yet. When you say lean do you mean I need more air now since I increases the fuel? Or do I still need more fuel? Which way would you turn it, out or in?
Thanks and sorry I am so slow to get this solved.

[Ryan'07400ex]

Ok so I finally went out "riding" yesterday and after getting to the factory I couldn't get the 400ex to want to stall like it had been so maybe it just takes a long time to warm up now. I think Im just gonna leave it alone... maybe it can't get any better.

Plus winter is coming along so maybe Im used to summer and shorter warm up periods :confused:

[f4iracer]

hey rocky mountain honda. I'm jetting with a lexx slip-on and a uni air filter lid on. Do you think 150, 40 would be a good start or should i start with 152, 42?

What combo do you think would be the best to start out with.

[rocky_mtn_honda]

depends on your altitude a little...but i wouldnt mess with the pilot...ive got the 38 pilot in mine...but i dont have any exhaust or filter yet...whats in it now? and whats your elevation?

[f4iracer]

right now i'm sitting at stock 38.

I've got a lexx slip-on. stock air filter with lid. Should i leave the pilot and just go up to a 152 main?

basically i jsut wanna prevent the machine from running too lean. so i'd like to be able to jet it pretty close with my only mod being the lexx slip-on.

thanks in advance rocky mountain

[rocky_mtn_honda]

post up a pic of your spark plug color...you may be able to tune it with the needle...you still didnt mention your altitude

[f4iracer]

600ft. elevation

spark plug color looks brown right now, i'm thinking about doing a 42 155 though cuz it's a bit lean.

also, i have an 07, so my needle is not adjustable. Would this be ok with the 155 main or do i need to buy a needle?

[katch26]

isnt the 07 fuel screw different too? everyone says flathead but its a weird d shaped screw and he would need to notch it for a flathead in order to use it.

somethings not seated right if its wanting to stall out on you during idle and slow riding. No matter how poorly mine was jetted it only did that when it had a airleak at the boot that the carb attaches too.....but thats my experience. In all fairness jetting is easy, the 400ex carb placement IS a pain though esp getting to that screw. When you pulled the bowl off a white ring probably fell off, it should go around the main jet but will only seat properly one way but can be forced on. I know mine kept wanting to fall off when putting the bowl back on.

I would put the 42 back in and leave that, and would focus more on a possible air leak. It sounds more like its leaning out.

from HMF forum but should be good info for you
2005 Honda 400EX fuel screws may have changed.
Normal fuel screws are slotted so that you can use a regular flat blade screw driver to make the adjustment.
We have had some people say that their fuel screws were "D" shaped, not a surprise that the EPA would make it harder to change the setting.
Dynojet does have a tool that comes in some of their street bike jet kits (Dynojet P/N DT009) but I don't think they would sell them seperate. Honda would probably have a special tool and Motion Pro makes a fuel screw wrench that includes the bit.
OR you could make one, heres how:
It would help to remove or tilt the carb so that you can see the fuel screw shape.
Get a 3/8 bolt, cut or grind one end flat so that you can drill a 11/64 hole in the center approx 1/4 in deep.
Then grind the outside diameter down to 15/64 approx 1/4down from the end. Yes, it will be thin but there isn't much room between the actual fuel screw and the diameter of the hole it fits in. Now look at the fuel screw, it is "D" shaped, you need to dent the OD that you just ground down to look like the "D" shape of the screw, go slow and tap the OD with a small hammer until you get the shape to fit the screw.
Kinda crude but it will work.

[f4iracer]

I didn't know about the a/f screw tool.

I've only adjusted my main jet so i was able to do that with a couple sockets.

I'll have to check into one of these tools as i'm planning on making some more carb adjustments