tuning help

[brandon32689]

So I pulled the carb today on my 03 400ex and went to a 42 pilot. The clip was on 3rd notch down and I seated air fuel screw and came out 2 n half turns i have a 180 jet in it right now and hmf slip on with k&n and open lid. It starts up and idles great I rode it down alley a few times and it seems good I dm getting a little backfire after letting off gas

[brandon32689]

So I drove it a few more times and it seems to do real good I get a little backfire every now n then afterva long run and letting off the throttle

[01boneless]

a little back fire indicates lean or an exaust leak check where the rxaust goes into the pipe also if that dont work go to 23/4 turns any more that 3 turns and you will have to go up a piliot but id say your real close (and i take it you dont need those pics lol that cool your learning)

[brandon32689]

Originally posted by 01boneless
a little back fire indicates lean or an exaust leak check where the rxaust goes into the pipe also if that dont work go to 23/4 turns any more that 3 turns and you will have to go up a piliot but id say your real close (and i take it you dont need those pics lol that cool your learning)

Ya man I just got after it this morning was not bad at all I dm on the 3rd notch down. I had a 38 pilot in there and put in the 42 also when I seated the air screw I noticed he had it out 3.5 turns. I went out 2 n half turns and put the 180 jet in. It starts right up and idles great and runs great just it would do that backfire every now n then and not very bad. Do I have to remove carb to turn that screw or us there a easier way. The plug looked really good after a few runs to

[brandon32689]

Also I double checked and I don't have a air leak Anywere I had that tiny one were it slipped on but I bought a new clamp this morning and put it on and the leak is completely gone

[01boneless]

well you can take a long flat head screwdriver and bend the tip 90 degrees and you could probley reach it

[BlasterEaten250]

Isn't a 180 main jet huge?

[CJM]

Originally posted by BlasterEaten250
Isn't a 180 main jet huge?

Thats what I said before in his other thread. Its gotta have an air leak somewhere-maybe the carb boots bad.

Or is he not using a true keihin jet?

[01boneless]

^^ pretty sure he said it was a dj jet but if it is a kehin than thats huge but if it runs good no leaks why worry im betting its beed bored :confused:

[brandon32689]

Well they rrcomrnd a 170 as a starting point and may need to go higher. There is no air leaks Anywere I've gone over it good.

If it was a dynojet 180 it would be close to a 200 keihin its a true jet has the k stamped in it. I might try dropping a jet or 2 after riding it

[CJM]

Yea dude, it seems INSANELY high. Imagine, a stock jet is 148, you have a 180 in there. Considering you dont have a larger displacement engine, and just an exhaust and a few other goodies its insane.

You also dont have genuine keihin jets, they have little stars on them. you may have knock offs, or oem keihin equivalents tho.

[brandon32689]

Ya it is the little star I just looked. Thought it was a k but it was the jets that came in the hmf jet kit I bought days gineiun jets ya I know some say its high some tell me its not I'm just trying to lean everything I can I looked all over net. I cent find a air leak Anywere on the machine and it runs and sounds great ill post a short video.

[brandon32689]

Also since I font know the history of the machine maybe it does have a bigger displacement. When I got it. It had the white bros and k&n and it had a 160 dynojet in it which is a 177 and it was running great

[CJM]

Probably is a higher displacement engine than stock then.

[honda400ex2003]

check out my pm for my input on the subject lol.

steve

[brandon32689]

Ya maybe your right the engine is really clean and sounds great. Fires up so easy n has good response. But I'm use to working on seadoos this is all new to me I appreciate everyone's help.


On another note my uncle just bought a yamaha raptor too. We were wondering if there was a site that sells new motors or rebiulds them like sbt does for seadoos. Just wondering. We usually did motor work ourselves on the skis

[brandon32689]

Originally posted by honda400ex2003
check out my pm for my input on the subject lol.

steve

Checked it out and replied. Thanks.

[01boneless]

tbh if its running that good and pulling hard i wouldent worry about it

[brandon32689]

Ya that's what I'm thinking but I'm all about previntive maintance and taking care if things lol. Usally my stuff lastes a ling time. If I get big into the 4 wheelers I'm gunna buy a brand new one.

[honda400ex2003]

what does the plug look like now that you went to the other/new settings?

still sounds rich to me with a 180. unless something is done internally a 180 is not going to be ideal for any stock bore engine. a 170 would hardly be ideal for any stock bore engine with extensive mods.

165 still gets my vote. give it a shot and see how it does. hmf can say what they want... a 170 with a full exhaust and filter is absurd to make any sort of decent power. they cover their hinders with jetting like that so people cant turn on them for burning up pistons.

steve

[brandon32689]

Originally posted by honda400ex2003
what does the plug look like now that you went to the other/new settings?

still sounds rich to me with a 180. unless something is done internally a 180 is not going to be ideal for any stock bore engine. a 170 would hardly be ideal for any stock bore engine with extensive mods.

165 still gets my vote. give it a shot and see how it does. hmf can say what they want... a 170 with a full exhaust and filter is absurd to make any sort of decent power. they cover their hinders with jetting like that so people cant turn on them for burning up pistons.

steve

The plug still looks pretty brown to me and it sounds good and runs good every now and then like i said it will backfire or do a sputter after letting off the gas at full throttle i have read that could mean rich and its burning off the excess gas, but idk. ya like i said i am brand new to all this lol i just seen on the hmf site for the slip on like i got it says 165/170 and for full system is like 180/200 the so should i go down to a 165 and see what the plug looks like then?

the only thing that sucks is that i do not know the history of the machine since i bought it used from a guy that bought it from someone and did not know anything, also i didnt know much about them so just bought it thinking it was a good deal ya know. It could be bored out and me not even know lol.

[honda400ex2003]

thats the tough part on buying used stuff, not knowing what was done to it before hand.

imo a 165 or 168 would be a much better choice. the 42 and 2.5 turns out on the f/a has your pilot circuit plenty rich not to backfire from being lean most likely. it might be worth going out to 2.75 turns out but i doubt that is needed.

my suggestion, go 168 and see how the plug looks and see how it runs.

change the plug, do a chop at WOT and check it out. if it looks good move onto the needle. get a new plug, go 1/2 throttle and do another plug chop.

do the same with an idle to see how it looks. get a new plug and let it run for a few minutes and kill it. do it a few times to see how it looks.

this would be the best jetting method to check all of them but really isnt needed.

check it out for a bit and see what you think. take pics of the plug and post them.

steve

[brandon32689]

Originally posted by honda400ex2003
thats the tough part on buying used stuff, not knowing what was done to it before hand.

imo a 165 or 168 would be a much better choice. the 42 and 2.5 turns out on the f/a has your pilot circuit plenty rich not to backfire from being lean most likely. it might be worth going out to 2.75 turns out but i doubt that is needed.

my suggestion, go 168 and see how the plug looks and see how it runs.

change the plug, do a chop at WOT and check it out. if it looks good move onto the needle. get a new plug, go 1/2 throttle and do another plug chop.

do the same with an idle to see how it looks. get a new plug and let it run for a few minutes and kill it. do it a few times to see how it looks.

this would be the best jetting method to check all of them but really isnt needed.

check it out for a bit and see what you think. take pics of the plug and post them.

steve


Okay thanks man I appreciate your help I will throw in a 168 if it cane with one tomorrow and do a few more test. I have checked it at idle and at half throttle and looks good both times. And the engine stays fairly cool imo for a air cooled. I wore shorts today and never once felt like it was to hot to ride.

I have checked the entire bike for leaks n don't find a thing. Here is a short video of it so you can hear it idle n rev not sure if sound quality but ill do mire test and report back. I'm just really wanting it to be tuned in good so it last. Oh ya not sure if I mentioned but I'm in west tx and its usually humid n hot and were 2800 ft abouve sea level.

https://www.youtube.com/watch?v=oKnC26Jw7nc&feature=youtube_gdata_player

[honda400ex2003]

if it doesnt feel hot at all it is too rich.

at least the needle and pilot are in good shape, the main is pretty easy once you get it closer. it is amazing how far off it can be and still run "good" once you get it closer to being in the sweet spot it will become a new machine. then the problem lies in keeping it running that great every day as the temps change, humidity changes, and barometric pressure changes lol. it will drive you insane haha

steve

[brandon32689]

Originally posted by honda400ex2003
if it doesnt feel hot at all it is too rich.

at least the needle and pilot are in good shape, the main is pretty easy once you get it closer. it is amazing how far off it can be and still run "good" once you get it closer to being in the sweet spot it will become a new machine. then the problem lies in keeping it running that great every day as the temps change, humidity changes, and barometric pressure changes lol. it will drive you insane haha

steve

Shoot man its already driving me insane lol. It was hot just not extremiky hot. I'm.just scared to go to lean with it and kill the motor. What are some things to look for that will show I'm running to mean? Ya I got the jet kit and we usually have a good winter like 30-50s so I figure ill go down pretty good come winter its usually tripple digits still right now every now n then we get like 85s lol.


Did u see the video.

[honda400ex2003]

if it starts backfiring badly and running rough it is running too lean. you will be able to tell the difference between how it sounds with a rich pop and a lean pop if you get one. lol

you will have to jet up for the winter not down. general rule of thumb for me is 2 sizes for winter compared to summer.

165 in summer is 170 winter for safety lol. i ride in anything though lol. 1 size would most likely suffice though depending on setup.

steve

[01boneless]

like steve said if nothing is done to the motor 180 is to rick but I am still wondering because it acully runs i would think if its that much to rich it would not even start but idk i say throw in a 168 2.5 turns 3 notch and youl be close belive me you will know if its to lean and if it is just dont run it long and go up a size depending on how bad it is . and props to you for being new and actulay using the search button!!!!!:muscle:

[brandon32689]

Okay thanks guys for all the help. I will do what yall say and report back. I should be able to tell I'm to lean before blowing motor up right like a few plug chops will be okay lol? I'm gunna get her done tomorrow guys. Guess its just trail and error.

Sweet so in the winter just go up about 2 that sounds easy enough.

[brandon32689]

okay guys today i looked threw my hmf kit i got and i did not have a 168 but i did have a 170 so i threw that in there and tried that first, keep in mind i live in city limits so until i can get to a track i can just get to about 3rd gear at full throttle for a few seconds and kill it and let it coast to a stop. I am doing this in the alley lol but i switched to the 170 let engine warm up and did a few passes then did the kill and checked the plug it seemed to run just as good as before but here are the pics of the plug do you think this is safe or should i go up or down a little.

http://i465.photobucket.com/albums/rr11/brandon3268921/SU1BRzEyODguanBn.jpg
http://i465.photobucket.com/albums/rr11/brandon3268921/SU1BRzEyOTAuanBn.jpg
http://i465.photobucket.com/albums/rr11/brandon3268921/SU1BRzEyOTMuanBn.jpg
http://i465.photobucket.com/albums/rr11/brandon3268921/SU1BRzEyOTUuanBn.jpg

[01boneless]

looks a little lean i still say its bored out :devil:

[brandon32689]

Could be I'm gunna leave the 170 in it and take it out sat and do a few more plug checks if it stays white or gets whiter ill go Bk to 180 if it seems good ill leave it or go down

[honda400ex2003]

you cant warm it up on a new plug then do the test. warm it up first, then change to a new plug, then do the test.

imo it still looks too rich, the electrode is just too dark for only a couple of passes on it. you would just have a ring at the bottom of the plug showing silver, brown or black in 3 passes that are a few seconds a piece.

there is also quite a bit of build up on the outer edge of the plug showing a rich condition.

it doesnt matter how fast you are going, just keep the revs up on the limiter as long as you can and as quickly as you can. 3rd gear is a good gear to do tests in.

just my opinion though...

steve

[brandon32689]

Oh okay well I dm using the same plug as before do I have to get a new plug for every test

[honda400ex2003]

every test needs a new plug also.

:D

steve

[brandon32689]

Dang Ima need a case of plugs lol. Would it be save to run it at the 170 jet? Will a little rich hurt anything. ? What is the lowest you would go with my set up.

[01boneless]

better rich than lean most prefer a little rick. and no it dosent i have the same stuff almost
uni filter no lid
slip on
and i run 158

[brandon32689]

Awsome man I may try like a 165 this weekend but I don't think I will go any lower than that because I gi not want to chance it lol. So I need go get to Honda shop and get a few more plugs and do some more testing. Can't Do much more till Saturday.

[honda400ex2003]

as stated rich is better for cooling and such. I would be comfortable running a 165 or 162 in my personal setup as long as i knew that it was jetted properly.

every machine is different so it can be hard to tell for sure but generally 165 is the going setting for these machines.

you will def go through alot of plugs your first time through if starting from scratch like that. you should be close enough to have it run good for you. getting it to run great is the tough part. as you can see you can have it run good with a 180 in it. the hp doesnt change much until it gets closer to the correct ratio for fuel and air of about 14:1 or so. this is pretty tight though, 13:1 is usually a good trail machine a/f. 14-14.5:1 is for race applications and most efficient burning.

heres an example of how much it changes based on different jets:
note this is for my case and is an example only.

i ran a 180 in my 416 and ran about 12:1 a/f ratio.

dropped to a 175 went to 12.5:1

dropped to a 168 went to 13:1

so 12 jet size different yielded 1 more full part less, granted this is quite a bit a/f change but an even bigger change over 12 jet sizes which is almost unheard of. I could have ran a 162 in it and got about 13.5:1 which would be race condition for a 400ex.

so 2-3 jet sizes isnt much to shake a stick at in the grand scheme of things. yeah it makes a difference but it isnt huge until you get to that "ideal" spot that can make it run superb for race application where it will be rebuilt soon anyway lol.

you are getting closer to the sweet spot now with a 170, a 165 would get you just about perfect. if it was me, i would probably leave it at 168 and call it a day after you get one, granted your plug looks good after a proper test and a thread cut to see the ceramic at the bottom. that will be the deciding factor in the whole scheme of things. after examination it might be worth the 165 and let er rip with that till it gets cold outside.

steve

[brandon32689]

Awsome man thanks for all your help so let me get this right. I'm going to buy about 3, new plugs. I am going to warm machine up pretty good and then put new plug in and do the plug chop? So I will do it with the 170 first and then try a 165?


So would you say don't go any lower than 165 with my setup? I might just leave 170 to cause I don't do to many straight ****s or racing. Mainly trails and hills and stuff.

[honda400ex2003]

yup warm it up first

change the plug

test



i would recommend to go to your proposed final jetting and run that first so you don't have to waste the plug if you don't have to.

i would go 165, 3rd notch, 42 pilot, 2.5 turns out and run it on a new plug

make sure you run it 4-5 times for as long as you can. (10 seconds or so if possible)

cut the threads off and check it out.

change or leave depending on how the plug looks.

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 your bike goes in each gear and where you're 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 hot!!!

5. read the plug.



:D
steve

[honda400ex2003]

your plug should look very similar to this after a test. this is pretty much perfect for a plug.

finally cut the plug i had in there. :D

http://img810.imageshack.us/img810/5743/img1234n.th.jpg (http://img810.imageshack.us/i/img1234n.jpg/)
http://img64.imageshack.us/img64/6229/img1233bq.th.jpg (http://img64.imageshack.us/i/img1233bq.jpg/)
http://img402.imageshack.us/img402/1046/img1232ff.th.jpg (http://img402.imageshack.us/i/img1232ff.jpg/)
http://img197.imageshack.us/img197/301/img1231qr.th.jpg (http://img197.imageshack.us/i/img1231qr.jpg/)

steve

[brandon32689]

Whats good to use to cut the plugs threads off.

[honda400ex2003]

i use a die grinder or a hack saw

then i take a pliers and break the threads

that is actually why the ceramic is broke on that one. lol i cut it too far back and snapped it all off when i went to pull the threads off.

steve

[brandon32689]

Okay cool so it is going to look a little white with just a slight tent to it. I see now. I'll do the best I can may just start off with the 165 and see what happens. Thanks for giving me all of your time and alll. I'm gunna try n get my plugs tomorrow n I orderd a little gopro main net tool to get them out easier so maybe I can tune it fast day n go ride rest of day

[honda400ex2003]

if the ring at the base of the ceramic is silver it is too lean

brown good

black rich

the one in the pic is brown at the base, silver will be a bit harder to see but under a good light will be visible. silver will also be lower on the ceramic after a few runs.

steve

[brandon32689]

Thanks man. I'm going to get it all done then

[honda400ex2003]

take your time, dont make more than 1 change at a time so that you can tell if it works or not.

:D
good luck
steve

[brandon32689]

Will do man thanks for all the advicec I'm going to try n leave everything as is and just change main jet

[honda400ex2003]

thats all you will need to do. the hard part is over.

do a comparitive test and see how each one looks.

170 test
judge good or bad

go up or down

repeat till brown if needed

:D

steve