PLUG COLOR, READ Now ...help (again)

[400exbiggun]

ok, just got done rejetting the carb, pulled the plug and it is so black, i have never seen a color so dark, it was black and DRY, do i really have to REJET it again? Will it hurt anything or just foul plugs???
oh yeah, 40pj, 160mj (dyno) and clip down one on stock

[Chanman420q]

your rich................

[Pappy]

how did you test the jetting....if it wasnt a wide open run then a quick shut down you better try again:p a rich low speed jet can be dealt with...you could be fine with the main. where do you have the nedle set? how many turns out on the air screw?

i dont know it all...just figured id ask:p

[400exbiggun]

air screw is set at stock postition, needle is up one from stock, i will do the main test now, just let it idle for a min. then looked at it, and it was on its way to black:(

[400exbiggun]

ok, just did a full throttle test down the road, and i pulled the blug, it is gray, kinda like a 400ex cylinder color, the side was black, and the electrode(i think it is that) under the little bridge was white, the thing around the little black thing:rolleyes:

so????????

[Pappy]

lil lean....think paper bag brown

[400exbiggun]

lean???...ya think???
huh, everyone said to put a 158 in, and i just left my 160 in, because i put a 158 and it backfired out the butt, and the plug was white?
it kinda looks like the normal one though, but only on full throttle
http://www.exriders.com/techarticles/images/sparkcolors.jpg
i bought it 3 months ago with the 160dyno jet, and experienced rich jetting though, but when i re jetted it , i guess i went even bigger though, what i am saying is that i rode for all that time with the jet, and nothing, but if it is a little lean, will it still hurt, i know about alot lean and the whole rings are cooked thing though? i am mainly train riding, some full throttle, but most like hill climbs.
i only took it down and up the road, so like tomorrow, i will go like a mile full throttle, will that get a true test?

[Pappy]

well its hard to tell over the net...but i always like mine a bit rich. my old 400 wouldnt color a plug for chit...it was either snow white or black as the ace of spades...i chit canned the dyno jet and used stock jets and it was perfect:confused2

[400exbiggun]

well, i think i will leave in the main,(then if it seizes, a reason to get my raptor or a big bore:D ) just kiddin, do have that kinda loot yet. yeah i will do a test later for the main, but if it is just a little lean like that, will it hurt any thing?
Also so to fix that black plug problem should i just move the air screw???
i really hate carb work, this would be the 7th time i pulled the carb apart in 1 week

[400exbiggun]

i will try to get a digi pis of it now, k?

[cals400ex]

are the dynojets about one size bigger or smaller than the keihins? i can't remember. also, are you running an airbox lid? big gun complete or slip on? what elevation you at? a big gun slip on with a K&N and lid in place runs good with a keihin 152 to 155. this is a few hundred feet above sea level. also, you can change the main jet without taking all of the plastic off. on the bottom of the carb there is a big bolt ( i think 17mm). all you need to do is unskrew it and the mainjet is right in there. its a lot quicker than taking the carb off to change the main.

[400exbiggun]

ummmm, i have the slipon. I just tried a 158 keihin, and it was too lean, it backfired and ran poor, so i put the 160 dynojet back in.
I am at around 700ft above sealevel.
i will have to look for that bolt then, huh...:ermm:
airbox lid is on.
everything is stock, except the pipe and filter (to the motor) and alot of people said to run a 152-158, so i ordered it from the dealer, waited 2 weeks, and put it in, and BAM, it ran soooooo bad, so i don't know.

[RIDER11X]

Originally posted by 400exbiggun
ummmm, i have the slipon. I just tried a 158 keihin, and it was too lean, it backfired and ran poor, so i put the 160 dynojet back in.
I am at around 700ft above sealevel.
i will have to look for that bolt then, huh...:ermm:
airbox lid is on.
everything is stock, except the pipe and filter (to the motor) and alot of people said to run a 152-158, so i ordered it from the dealer, waited 2 weeks, and put it in, and BAM, it ran soooooo bad, so i don't know.
For an HMF slipon, they reccomend starting w/ a 175 Keihin, but that is a bit rich for most people. Some riders I talked to ended up using a 165-168 w/ a lid and 6 - 1" vents. Oh, and we are at 1200ft. elevation. :confused2 Hope that helps.

WHY DON"T DEALERSHIPS STOCK ALL JETS??????? I ran into that before.:cuss: They sell pipes but ask for some jets and " Sorry dude, I don't stock any jets." :huh :huh :huh

[300exHILLER]

Dyno jet is about +10 of regular jets. So a 160 dyno jet is ~ 150 regular jet. I just went through this on my quad and Took the carb off 9 times before I figured this out and got it right.

[400exbiggun]

so guys, how would i make the other jets leaner? Without changing the pilot jet???

[cals400ex]

put in a bigger pilot. also move the clip on the needle one down. this will make the other jets richer.

[Dunlap]

With all the different kinds of fuel we see (including unleaded) there is no way to get the right color.The way I read a plug is to ride for 10-15 min. to get it up to temp.Run down the road wide open in the top gear and hold it there for 5-10 sec. then kill the motor, pulling in the clucth and come to a stop. Pull the plug and look at the ground strap,you want to see a carbon line in the middle of the 90*bend. If the line is closer to the tip of the strap its to rich. If it is down around the 90* bend towards the plug threads its to lean.This works on 2 and 4 strokes.It does not matter what color the plug is just make sure you use a used plug that has carbon on it.

[chad502ex]

Originally posted by Mickey Dunlap
With all the different kinds of fuel we see (including unleaded) there is no way to get the right color.The way I read a plug is to ride for 10-15 min. to get it up to temp.Run down the road wide open in the top gear and hold it there for 5-10 sec. then kill the motor, pulling in the clucth and come to a stop. Pull the plug and look at the ground strap,you want to see a carbon line in the middle of the 90*bend. If the line is closer to the tip of the strap its to rich. If it is down around the 90* bend towards the plug threads its to lean.This works on 2 and 4 strokes.It does not matter what color the plug is just make sure you use a used plug that has carbon on it.

I've heard the same thing thru the grapevine. This works for me and my friends too, but only dials in the top end of the powerband. You can still load up a plug on the bottom end if your needle isn't positioned correctly. A dyno works great too with a "Sniffer" up the exhaust to sample the CO2's, but its costly to rent time. Actually, I think I remember hearing years ago that a Asian mechanic (maybe from HONDA) told the "Lead HONDA Race Team Mechanic" how to do this. hmmmmm,...Back in the day, weren't you HONDA's Race Team Lead Mechanic? just curious if the rumor was true.

[Dunlap]

Get a life looser!

[JOEX]

Originally posted by Mickey Dunlap
With all the different kinds of fuel we see (including unleaded) there is no way to get the right color.The way I read a plug is to ride for 10-15 min. to get it up to temp.Run down the road wide open in the top gear and hold it there for 5-10 sec. then kill the motor, pulling in the clucth and come to a stop. Pull the plug and look at the ground strap,you want to see a carbon line in the middle of the 90*bend. If the line is closer to the tip of the strap its to rich. If it is down around the 90* bend towards the plug threads its to lean.This works on 2 and 4 strokes.It does not matter what color the plug is just make sure you use a used plug that has carbon on it.
I haven't done one of these tests yet but would like to, I have a few questions.....
Why is it neccessary to be in top gear? Will a lower speed with equal engine rpm have the same result?
Does it matter if the road is level or not?
Will the carbon line be perpindicular to the ground strap? And how wide/thick will it be? Do you have any pics of what we should be looking for?
Can this test be done on the other carb. circuts?

Thanks for your time, Joe

[White_Knuckles]

Originally posted by 300exHILLER
Dyno jet is about +10 of regular jets. So a 160 dyno jet is ~ 150 regular jet. I just went through this on my quad and Took the carb off 9 times before I figured this out and got it right.

Yikes! the common rule quoted from a tech site below:

It would be noted that Dynojet main jets as used here are, because of their better flow characteristics, effectively one size larger than standard Keihin jets, i.e. Dynojet 118s are equivalent to standard Keihin 120.

+10 is way too much .... sorry, remember the increments are like 105, 108, 110, 112 etc. Drop or raise one size to convert.

[White_Knuckles]

Reading Mr. plug can be Voodoo at best with today's lean fuel. Try this test, I have used it when reading plugs made me crazy.


The Roll-Off technique is the quickest and is almost as accurate as the Roll-On method. First, one gets the engine warm on the way to a safe roadway. If there is room, use fourth gear as this allows more time to assess the result.

Now, get the engine rpm high enough that it is on the cam and in its power band. This may need to be as high as 4000 rpm with some cam choices. Apply full throttle. Let the engine accelerate for a couple of seconds until it has settled in and is pulling hard. Quickly roll the throttle off to about the 7/8ths position. When you do this, the mixture richens slightly for a second or so.
If the engine gains power as you roll the throttle off, then the main jet is too small and you need to fit a larger one.
If the engine staggers slightly or has a hard hesitation, then the main jet is too large and you need to fit a smaller one.

[Dunlap]

First of all, I like to use stock Kiehn jets so there is no confusion when I am talking to a customer. I always set the main jet first. The reason why you run in top gear is to put as much load to the motor as possible. I run mine up a pretty good incline for about 1/4 mile. Build as much heat into it as you can to test the jetting correctly (like you are racing it). On the east coast on most of my motors, I find that changing the needle or pilot jet is usually not necessary but this is on a built motor and most of the time they run more efficiently the more you build them. Every pipe that I have installed on a stocker we run a 155 main jet period. You may have to turn the fuel screw out 1 to 1-1/2 turns out further than stock to keep it from backfiring when you let off on it and to warm up a little quicker. When you have a good carbon line it will be very distinct. It is basically burning off the carbon down to that point which should be right in the middle of the 90 degree bend. Once you get the main jet set if you have to change the rest of the carberator settings it will be just a trial and error to get the best throttle response.

[JOEX]

Thanks Mickey:)
A couple more questions:p

Does the fuel screw affect all carb circuts? For some reason I thought it was just just the idle/pilot circut.
When talking about the carbon burn off is it from the tip of the strap to bend?

What do you think of White_Knuckles response? This person has been posting alot of good technical info here lately. Seems to on the up and up:)

Thanks again, Joe

[Dunlap]

Yes on the first 2 ?s. As far as White's way yes this is good if you have a good feel for motor's. I deal with people every day that don't realy know what the motor is doing so this let's them see it for them selves,but for someone who does this alot you don't even need to pull the plug to know when it's right.

[400exbiggun]

wow, some good useful info, i don't know if i missed anyone saying this, but then how do i check with the plug if the pilot and needle are set right???????:confused:

Frickin frackin jetting :grr: its so much fun LMAO

Good info guys, thanx

I got to agree that just checking color will drive you a little nuts. I had tried that method and just when the machine feels like its pulling hard thru the entire rpm range you pop the plug and say hmmmmmm whats this black stuff all about :)

I remember when I had first started dialing in the jetting on the EX and someone had recomended a main size (158 I think) and claimed to try and work down from there. Well the plug read that nice med brown but the engine was super zingy (almost like a small 2 smoke) and so low on power that you could feel it was looking for more fuel. So much for plug color.

For those who care I gave away all the dyno crap jets long ago because its just confusing with the two diff jets and the dynos just add another part (the adapter) to come loose etc. and I am sure Keihin knows how to make jets for their own carbs.

[Pappy]

im thinking of getting the small probe for my EGT and using it. i dont know how far from the cylinder to place it but im sure the manufacture could tell me. i used this on my race car and was hooked:p

[RIDER11X]

Originally posted by 440EX4me
Frickin frackin jetting :grr: its so much fun LMAO

Good info guys, thanx

I got to agree that just checking color will drive you a little nuts. I had tried that method and just when the machine feels like its pulling hard thru the entire rpm range you pop the plug and say hmmmmmm whats this black stuff all about :)

I remember when I had first started dialing in the jetting on the EX and someone had recomended a main size (158 I think) and claimed to try and work down from there. Well the plug read that nice med brown but the engine was super zingy (almost like a small 2 smoke) and so low on power that you could feel it was looking for more fuel. So much for plug color.

Perfomance testing is the best method, I agree! What size main did you end up using?

[chad502ex]

the only "loser" I see in this thread is the one that's lost some business!! Alot of perspective customers read these threads and when so-called business owners post unprofessional messages, it just makes the new customers realize how they could be treated for having an opinion. As far as putting yourself in the TC, Sparks category, not even close. They build incredible motors that last more than "OneLap" and are extremely professional to their customers. Those guys are stellar.


Of coarse this is only my opinion,... which doesn't matter any too you, and is probally the reason why you continue to debate matters.

Just ride the dam thing and the motor will tell you if it's needing gas or not gettin enough..

That's my plug check method...:devil:

[400exbiggun]

Originally posted by Mickey Dunlap
With all the different kinds of fuel we see (including unleaded) there is no way to get the right color.The way I read a plug is to ride for 10-15 min. to get it up to temp.Run down the road wide open in the top gear and hold it there for 5-10 sec. then kill the motor, pulling in the clucth and come to a stop. Pull the plug and look at the ground strap,you want to see a carbon line in the middle of the 90*bend. If the line is closer to the tip of the strap its to rich. If it is down around the 90* bend towards the plug threads its to lean.This works on 2 and 4 strokes.It does not matter what color the plug is just make sure you use a used plug that has carbon on it.



well i just did that, pulled the plud, and the sides are black, and that bridge has carbon on the side below the bend, on top it is gray. but i am currently running only regular unleaded, since i had no chance to get to a gas station.
But then this says it is lean right, but i bought it with the 160dyno, took it out and cleaned it, now it says lean? what?

Originally posted by 400exbiggun
well i just did that, pulled the plud, and the sides are black, and that bridge has carbon on the side below the bend, on top it is gray. but i am currently running only regular unleaded, since i had no chance to get to a gas station.
But then this says it is lean right, but i bought it with the 160dyno, took it out and cleaned it, now it says lean? what?

dude your pissin in the wind with these plug checks..I'm tellin ya.

Yes they work but you'll get so many readings and it sounds like your running 87 octane at the most.

Ride the mofo and listen to the motor...work smarter not harder..;)

[400exbiggun]

ummm..ok, i always put in 93 or higher octane, but we only had the 87 in the garage. yeah i think i will screw the plug checks.

[Texan32]

Rico is right. The motor will tell you if it needs adjusting. If it isn't obvious, then there isn't enough rich or lean condition to do any damage. Besides, a 160 main with just a slip on, you'll be fine!!

[400exbiggun]

thanks, thats what i was thinking, sounds good
this site is prob..the best site for useful info. bluetraxx is ok, but not even about the yamaha's do they give good info.
thanks again

[RIDER11X]

Originally posted by 400exbiggun
ummm..ok, i always put in 93 or higher octane, but we only had the 87 in the garage. yeah i think i will screw the plug checks.


That will throw off any readings or motor signs. Octane draws oxygen into the fuel and will affect this. My old 250x ran very rich, when I added 104+ octane booster the rich condition disappeared. ( I did this as an Experiment) :cool:

Originally posted by RIDER11X
Perfomance testing is the best method, I agree! What size main did you end up using?

After the last rebuild (late fall last year)I found a 178 to be pretty much spot on. In the colder months it was up to a 182 and recently at Hatfield I dorpped down to a 170 with the higher temps and elevations. This worked great till the silencer cracked off at the header and opened up all the back pressure. The needle is still to this day a little rich but if dropped one notch it gets real zingy till you hit the main.

I still have the 170 in there and just installed a UNI foam filter I had picked up as a spare and now its richened up again and blowing a black cloud from 1/2 to full throttle so I guess it isnt flowing as much as the K&N. :)

Originally posted by chad502ex
the only "loser" I see in this thread is the one that's lost some business!! Alot of perspective customers read these threads and when so-called business owners post unprofessional messages, it just makes the new customers realize how they could be treated for having an opinion. As far as putting yourself in the TC, Sparks category, not even close. They build incredible motors that last more than "OneLap" and are extremely professional to their customers. Those guys are stellar.


Of coarse this is only my opinion,... which doesn't matter any too you, and is probally the reason why you continue to debate matters.



Hey you baited the trap so dont get your panties in a bunch because he didnt bite, try harder next time. :blah:

I dont know any of these guys personally but I do know that is was and is Mickey that has taken his time to help this site with two Q&A pages that were both informative and helpfull, and is on here offering his experience to our members on a regualar basis. I dont see the others doing this and from my conversations with them I dont expect anything more. Guess there too big or busy :rolleyes:

And BTW I would take an FST engine over a TC or sparks anyday :D :blah: :devil: :macho

So please lets not badger and harass the builders who take their time out of their day for us so they continue to do so.

Ride the mofo and listen to the motor...work smarter not harder..

Good advice Rico but you got to think about the majority of riders dont know what there listening or feeling for etc. Its not all that easy either when you dont ride often and just dust it off and go.

I have rode with people who have had some interesting problems and never had a clue anything was wrong. One time I was helping someone change out a plug on a raptor and couldnt even believe it ran it was so carbon fouled though he did notice that it ran better, but still had no idea there was a problem in the first place till it was hard to start.

theres many more but you get the idea I am sure.

[Pappy]

Originally posted by 440EX4me
I dont see the others doing this and from my conversations with them I dont expect anything more. Guess there too big or busy :rolleyes:



no...the others are here too...they just hide behind a ficticous name and post...and everyone gets that they are smart but we have no way of knowing who the hell they are:eek: i know 2 of the other "big" builders secret names.....and its funny watching someone tell them they are wrong.....lmfao

[chad502ex]

Originally posted by 440EX4me
Hey you baited the trap so dont get your panties in a bunch because he didnt bite, try harder next time. :blah:

I dont know any of these guys personally but I do know that is was and is Mickey that has taken his time to help this site with two Q&A pages that were both informative and helpfull, and is on here offering his experience to our members on a regualar basis. I dont see the others doing this and from my conversations with them I dont expect anything more. Guess there too big or busy :rolleyes:

And BTW I would take an FST engine over a TC or sparks anyday :D :blah: :devil: :macho

So please lets not badger and harass the builders who take their time out of their day for us so they continue to do so.

440ex4me, ok, i get your message.

[RIDER11X]

Originally posted by 440EX4me

So please lets not badger and harass the builders who take their time out of their day for us so they continue to do so.
DITTO!

[JOEX]

So please lets not badger and harass the builders who take their time out of their day for us so they continue to do so. [/B]
WORD!!

Originally posted by Pappy
no...the others are here too...they just hide behind a ficticous name and post...and everyone gets that they are smart but we have no way of knowing who the hell they are:eek: i know 2 of the other "big" builders secret names.....and its funny watching someone tell them they are wrong.....lmfao
I always wonder how many "BIG" builders/manufactures that are here lurking...and who they are. I know they are here....I just wonder what they think of what goes on here.

Joe

[Pappy]

truthfully the ones ive talked to cant relate to the site. they work non stop and dont have the free time to read every thread:p but they are here...along with almost every chassis builder you can think of.

i would be extstatic if i had the instant consumer feedback in my business thats available here. other then those that live in dream world there is some real good info here for companies that are smart enough to "GET" what people are saying and asking for:bandit:

btw...did this kid ever get his quad jetted:p

[JOEX]

Did someone have a jetting question?!?! LOL!

I know they are here leeching info from us which is great but I still have that curiosity of who they reallly are. Maybe it's better we don't know and post freely without having to worry about what the "BIG" people will say and react...

Joe

[JD400exrider]

Originally posted by 440EX4me

So please lets not badger and harass the builders who take their time out of their day for us so they continue to do so. [/B]

Agreed

Originally posted by Pappy
no...the others are here too...they just hide behind a ficticous name and post...and everyone gets that they are smart but we have no way of knowing who the hell they are:eek: i know 2 of the other "big" builders secret names.....and its funny watching someone tell them they are wrong.....lmfao

I agree there and have even had pm talks with more than one but they arent giving up the real deal etc. and I am fine with this but just cant ignore the potential benefits of both the obvious and sly covert "experts" that are offering real info.

Glad to see I said something right again :) or that atleast someone agrees we shouldnt be bashing these guys.

Now there are a couple I have some issues with but you wont see it here untill things are worked out either good or bad but worked out :D

Hey from one prob I may have found an answer to problems with the aftermarket a-arm bushings that wear prematurely so nothings all bad.