What's Your Jetting?

[clemsonteg]

I know we all see threads on what jets would be recommended for each setup. I know every bike is different, but I figured if everyone would state any mods they have, the elevation they ride at, and what jets (size and type) and a/f screw setting you are running people could look here and get an estimate of where to start.

You can check your elevation here

http://www.earthtools.org/


That being said, I would post mine up also, but I have no idea because the bike already had a pipe and dynojet jets in it and I haven't broke into it yet to check it out. :devil: I do however plan to switch to keihn jets and I want to buy a new slip on so maybe when it warms up a bit.

[honda400ex2003]

heres mine 1500ft. steve

[clemsonteg]

Originally posted by honda400ex2003
heres mine 1500ft. steve

Right off the bat that is interesting. I was looking at getting an HMF slip on, and HMF recommends a 165-170 keihn with just the slip on (at 900 ft) but you obviously have much more with a 170 keihn. I guess running what I would think is pig rich is their way of making it safe for everyone.

[honda400ex2003]

you should be right around a 158-160 or so in my opinion. steve

[JOHNDOE83]

Florida at sea level...190 main 50 pilot... with my mods...

[clemsonteg]

Originally posted by honda400ex2003
you should be right around a 158-160 or so in my opinion. steve

I was actually thinking around 152-155, that seems to be the most I see recommended for a slip on and filter with the lid on, if and when I get there I was planning on ordering a 152, 155, and a 158 just for shiggles.

[honda400ex2003]

155 is what i used to run with my t-4 and k&n with my lid on. I would start with a 158 and see how it being that low. steve

[clemsonteg]

Originally posted by honda400ex2003
155 is what i used to run with my t-4 and k&n with my lid on. I would start with a 158 and see how it being that low. steve

Yeah Im actually at around 800 ft at my house which is where I ride mostly.

I guess weather would play a fairly large factor too. Its usually pretty warm and humid when I ride.

[honda400ex2003]

you would definitely be really rich with a 160 in the heat and humidity. the colder it gets the bigger the jets you can run since the air is thinner in the cold, you can get more flow through it. steve

[gtt416ex]

42 pilot
150 main
needle on middle clip
2 1/4 turns out on a/f screw
742 ft above sea level

[clemsonteg]

Originally posted by gtt416ex
42 pilot
150 main
needle on middle clip
2 1/4 turns out on a/f screw
742 ft above sea level

What Engine mods do you have?

[gtt416ex]

87mm 11:1 wiseco piston
Hot cam stg 2 cam
white bros. e series slip-on
K&n filter with the airbox lid removed

[HY400EX]

I am going to install a Lexx slip on with the stock air box lid on. With a stock 2004 400ex at 2000 feet elevation and for the climate I am in ny. I will also be runnning with the quite core in. I have the stock 148 and I was going to go with a 155 Keihin would that work? Or is a 155 to rich? I would rather be a little rich than to lean.

[honda400ex2003]

you should be pretty close with that. go 3 turns out on the f/a screw, leave the needle alone. you should be pretty good to get it running and tune it a bit. steve

[Wheelie]

Mods are in sig.

Jetting

62 pilot
245 main (est using jet drill chart, I have to drill my own jets)
HRC Needle on bottom notch and shimmed

A/F screw out 3 turns

I ride from 0-3000ft with this jetting and it works great, albeit slightly rich at higher elevations.

[honda400ex2003]

just curious, you couldnt find any 450 jets that worked that seems really big but you have a pretty kicking motor you are pumping. lol. steve

[Wheelie]

Originally posted by honda400ex2003
just curious, you couldnt find any 450 jets that worked that seems really big but you have a pretty kicking motor you are pumping. lol. steve

The largest production Keihin jet is a 230, anything after that drilling is required.

I was running a 240 for awhile, it ran great. Got bored one day, installed the 245 and picked up a noticeable amount of torque without losing top end power.

It drinks the fuel, but it's well worth it.

[honda400ex2003]

NICE bro lol. that is a ton of gas getting sucked into it. steve

[sandspanker]

Originally posted by honda400ex2003
you would definitely be really rich with a 160 in the heat and humidity. the colder it gets the bigger the jets you can run since the air is thinner in the cold, you can get more flow through it. steve this one is wrong... the colder it gets the more dense the air gets. the heaver it gets.. in turn fills the volume of the cylinder faster.. the warmer the air is the thinner it gets which makes the quad run richer in which you would have to lean it out.

[honda400ex2003]

i had the concept right lol just mixed up the thinner air part. lol i get it mixed up once in a while. I was thinking about the elevation changes instead of temp. As you go up the air gets thinner. lol you have to jet up for the cold down for warmer. lol. steve

[clemsonteg]

Originally posted by honda400ex2003
i had the concept right lol just mixed up the thinner air part. lol i get it mixed up once in a while. I was thinking about the elevation changes instead of temp. As you go up the air gets thinner. lol you have to jet up for the cold down for warmer. lol. steve

Yeah I knew what you meant. I plan to shoot in the middle at a 155 for mine and see where that puts me.

[atb400ex]

would a port and polish/ stage 1 cam affect jetting because i have the same setup as honda400ex2003 minus those and im at about the same elevation.

[honda400ex2003]

port and polish will a little but the cam shouldnt. I would start with my jetting and check the plug a couple of times to see if you have to change anything. check out plug chopping in a search and you should find some good stuff on it. i just posted directions on it last week on one so there should be a recent one like 5 pages in or so. steve

[Miami_Vice454]

NICE bro lol. that is a ton of gas getting sucked into it. steve

well if you notice he is on e85 and ethanol burns alot faster and you us alot more. the reason why you need so much more fuel i dont know lol

[atb400ex]

Originally posted by honda400ex2003
port and polish will a little but the cam shouldnt. I would start with my jetting and check the plug a couple of times to see if you have to change anything. check out plug chopping in a search and you should find some good stuff on it. i just posted directions on it last week on one so there should be a recent one like 5 pages in or so. steve

sweet thanks!

[honda400ex2003]

Originally posted by Miami_Vice454
well if you notice he is on e85 and ethanol burns alot faster and you us alot more. the reason why you need so much more fuel i dont know lol

that is correct. you can get pretty heavy on the e85. lol. it works good with 105 octane also, you can keep the motor running cool along with running 12:1 comp on cheaper gasoline. steve

[honda400ex2003]

plug chopping
the plug chop is an essential step in setting up jetting. not only does it help you get good performance, but more importantly, it helps you make sure yr bike is not running so lean that it will blow up!

1. wind it out! . warm the bike up well (5-10 min) with a new or fairly clean plug, correctly gapped, then wind the bike out in a gear. generally, i like to do this in 3d, but it depends how fast yr bike goes in each gear and where y'r doing this test (trying to run a bike out in 4th is not advisable in, say, a school zone). at least get into 2d.

2. hold it there ... even though you will be nervous, hold it in gear at max rpm for a while... what you are trying to do here is simulate the hardest use the bike will ever conceivably see. if you jet for the most stressful conditions, then yr normal use will be well within safe margins. keep yr hand on the clutch, as you could (doubt it, though) seize if you are jetted too lean to begin with. as always, use yr own judgment!

3. kill it. simultaneously hit the kill switch and pull in the clutch. hitting the kill stops the plug sparking; pulling the clutch stops the clutch from turning the engine over (bringing in more unburnt fuel). thus, you get a perfect picture of what the sparkplug looks like at the moment you hit the kill switch.

4. pull over, pull the plug out you will want to have gloves or a set of pliers, cause the plug will be fking hot!!!

5. read the plug. if the plug is:

black and wet: yr jetting is too rich

chocolate brown: yr jetting is right on! you kick ***!

white and burnt smelling: yr jetting is too lean! upjet now . you might also notice a blistered insulator. this is real bad. you are lucky you haven't hurt yr bike worse!


here it is again. steve

[moddedblaster20]

hey everyone. my elevation is about 121. i have a slip on, k&n filter with an open box, 416 kit, hot cam. my main jet is 170 and pilot is 40. what does this sound liek to you guys?

[atb400ex]

Originally posted by honda400ex2003
plug chopping
the plug chop is an essential step in setting up jetting. not only does it help you get good performance, but more importantly, it helps you make sure yr bike is not running so lean that it will blow up!

1. wind it out! . warm the bike up well (5-10 min) with a new or fairly clean plug, correctly gapped, then wind the bike out in a gear. generally, i like to do this in 3d, but it depends how fast yr bike goes in each gear and where y'r doing this test (trying to run a bike out in 4th is not advisable in, say, a school zone). at least get into 2d.

2. hold it there ... even though you will be nervous, hold it in gear at max rpm for a while... what you are trying to do here is simulate the hardest use the bike will ever conceivably see. if you jet for the most stressful conditions, then yr normal use will be well within safe margins. keep yr hand on the clutch, as you could (doubt it, though) seize if you are jetted too lean to begin with. as always, use yr own judgment!

3. kill it. simultaneously hit the kill switch and pull in the clutch. hitting the kill stops the plug sparking; pulling the clutch stops the clutch from turning the engine over (bringing in more unburnt fuel). thus, you get a perfect picture of what the sparkplug looks like at the moment you hit the kill switch.

4. pull over, pull the plug out you will want to have gloves or a set of pliers, cause the plug will be fking hot!!!

5. read the plug. if the plug is:

black and wet: yr jetting is too rich

chocolate brown: yr jetting is right on! you kick ***!

white and burnt smelling: yr jetting is too lean! upjet now . you might also notice a blistered insulator. this is real bad. you are lucky you haven't hurt yr bike worse!


here it is again. steve
even better thanks!

[honda400ex2003]

Originally posted by moddedblaster20
hey everyone. my elevation is about 121. i have a slip on, k&n filter with an open box, 416 kit, hot cam. my main jet is 170 and pilot is 40. what does this sound liek to you guys?

it may be a tad lean. maybe a 172 would be better but you can try the 170 first if you like. steve

[moddedblaster20]

yes a 170 is in it now. do i go down sizes when the warmer weather comes? thanks

[honda400ex2003]

most likely yes. you will probably be looking somewhere around a 168 or 166. a general concensous that i have found over the years is every 20 degrees is a jet size but i am not sure how close that actually is. i went to a 172 for the winter and it seemed to be close enough to get me through the colder stuff but when it was 30 out it was a bit too rich. once it got down to the 10s and 0 it was pretty good i guess so i still stick with it as being a good guesstimate. i have mine jetted for right around 50 degrees with the 170 so it is spot on there so when it gets a bit warmer it is a bit richer to help keep it cooler without sacrificing any noticable power until it starts to get really hot like in 80-90. it starts to get sluggish again at those temps but it is reassuring to know that it is rich enough not to burn up or overheat. lol. steve

[moddedblaster20]

ok thanks man! ill get a few jets to play around with when it gets warmer. off topic but figured youd know. what are all the possiblities of how gas is getting in my oil? my oil smells a little like gas and is a hair on the greyish color.

[honda400ex2003]

blow by from your rings most likely. other than that there is no place for gas to get down there. lol. it may be time to do a compression test and leak down test. see what they are and possibly do a rebuild on it. steve

[moddedblaster20]

alright man thanks. from what i was told it wasnt rebuilt too long ago before i bought it from the dealer

[olwhitey]

hey guys i just got my 440 running and it seems like its gonna hold together this time so its time to tune it. I have a 89mm big bore kit wit stage 2 cam and full white bros exhaust. what jets should i be running and carb tuning should i run?

[clemsonteg]

I can bring this thread back up now cause I rejetted mine yesterday.

FMF Powercore 4 slip on
Uni Filter with outerwears over it
Lid On
800ft elevation

158 Main, 42 pilot, 2.5 turns out, and 3rd notch on a dynojet needle

It shouldn't make a difference but my jets are Pro X Keihn aftermarket jets. I don't think they are made by Keihn but they work well and seem to have the same measuring scale as the factory jets.

[bkelley]

White Bros. E-Series
ESR Airbox Eliminator Kit
42mm 450r Carb
Evlevation: 1,800 ft

168 Keihin main, 52 pilot, 3 turns on f/a, and Dynojet needle on the third clip.

I still get a tiny big of bogging when I'm high into the RPMs and it backfires every so often on deceleration. Think I'm just a tad bit rich, but I feel like the 165 would be too lean since I am so close right now. Guess I just need to put one in and see. Other than that it runs fine. Cold blooded, but starts and runs fine.

[clemsonteg]

mine starts so much better now the the new pilot jet, literally I can go out and leave the choke off, open the gas valve and it fires right up and starts to idle for me.

[bkelley]

Mine is super cold blooded. It takes a good 20-30 seconds to get it to start. Once it gets going it's fine. I can't use the choke because the carb is too big for the lever to move haha. Need to make my own lever.

[mineralgrey01gt]

mine is the same way. It takes a little to crank but itll fire up. I just took my lever off. If I have to use choke I have to take my plastics off and get it with a flat head screwdriver. Mine took about 20 seconds today to crank

[bkelley]

If it doesn't want to fire up I'll take the filter off and put my hand over the intake and choke it manually. Only had to do that once and that was because it was really cold out.

[bherriman]

40 pilot, 155 main and about 2.5 to 2.75 turns on the screw. I've got the lid on with a couple small holes along with the mods in my sig

[slightlybent47]

48 pilot 202 main. 100-200 elevation
Mods are 416
12/1 comp.
Over sized oil tank,
p&p,
stg 2 cam,
White bro mx4 slip on,
stock head pipe (welds ground)
Open air box and 05-450 carb.
Half & half race gas and 93 pump gas

[krt400ex]

500ft above sea level. was running a full yoshi rs3 oval system and i was running a K42 pilot and K155 main with the fuel screw on 2 1/4 turns out. bike ran mint

[mineralgrey01gt]

0-30ft above sea level with my mods in sig:

205 main
52 pilot
3 1/4 turns out

still stays up in idle a little on deceleration but not bad, comes right back down quickly. Might bump the pilot down to a 50 other than that its spot on

[Wr3sTl3b0y]

so i feel like im holding back some power
2001 440 big bore kit stage 2 camshaft k&n filter just put a 172 main in it got a ~42 pilot im thinking i need to go higher on both of them just not sure how much

[Pabst_Powered]

600+ft above sea level

-SuperTrapp IDS2 slip-on
-K&N Powerlid
-K&N air filter
-DynoJet kit
-165 main
-40 pilot
-2 1/2 turns A/F screw

[bkelley]

Anyone know if the 400ex and 450r needles are interchangeable?

[mineralgrey01gt]

Originally posted by Wr3sTl3b0y
so i feel like im holding back some power
2001 440 big bore kit stage 2 camshaft k&n filter just put a 172 main in it got a ~42 pilot im thinking i need to go higher on both of them just not sure how much

if your plug is good i wouldnt change it