still reads lean, help!!!

[RIKR4X]

I just put a 170 main in and a new plug. took off my air box lid,did 2 full out runs killed it and checked plug. it was still white ,the threads were black but the electrode was white!! im sick of hearing my buddy brag how his stock bike beats mine,we use to be dead even before i did pipe and jetting. PLEASE HELP!!! THANKS.

[400exJOE]

ok, calm down. Reading a plug is usaully a pretty good sign of how your engine is running but it really comes down to does the quad run well? By that i mean after its warmed up, are there any misses or flat spots in the power band? Also, do you have a full exhaust or just silencer? My last Q is what is your altitude of where you live? That can greatly affect what your jetting should be. I see your from Illonois so you should be about right with your jetting. One thing i would try is put the air box lid on. That should richen it up a little and check to see if your mixture screw is right. Should be 2.5 turns out from when it sets.

[RIKR4X]

I just have a slip on. i think im at sea level,the other thing is when its sitting still and i gas it hard it puffs a little black smoke, but it dont cut out or backfire when im riding it full out. the mechanic at my local dealer has a 170 & no lid he told me to do that?

[400exJOE]

i think i would pay a visit to the mechanic. Black smoke is never a good sign. Another thing, engines should NOT be run lean for extended periods of time. I hope that you have not been riding the quad like this for a month now. Running a quad lean can cause a lot of damage to the engine. I am not trying to scare you but I would deffinatly see the dealer or a shop about this.

[RIKR4X]

its only puffed the black smoke since i put in the 170 and its not alot. i dot think theres a problem there. cause it didnt do that with the 155. thanks.

[Wheelie]

You are way to rich with the 170mj and your setup.

I see in your signature a 42pj and a 158mj. Do you still have the 42pj? Try going back the 155mj, and try a 40pj. IMHO a plug test will usually cause an error when it comes to jetting. Go with a seat of the pants feel. Here's the rule I follow, I've found it to work very well.

If the acceleration suffers in the lower gears, but it seems alright in the higher gears...namely 4th and 5th it's too lean. If acceleration is good in the lower gears, but feels 'flat' in the higher gears......your're too rich.

I've got the same setup: E-Series slip on, K&N, one BIG hole in my airbox lid. After piping it I went to a 160mj, it seemed to run better before I piped it, I knew something was wrong. I read an article and stepped down to a 158, it ran better, had more top end power and speed and better hill climbing power. I stepped down again to a 155 and it ran even better, and that's where I left it.

I live at 1400ft and do a lot of riding at the beach with a 40pj, 155mj and the clip on the needle lowered one notch....runs great!

Sorry so long....Good Luck!!

[RIKR4X]

are you saying im geting a false reading from the 42 p? ill go bye a 40 tomorrow. it does pull hard low but dont feel that great in high gear. what is imho? I never messed with my needle.do you sugesst leaving the lid off?do you feel your bike is faster than a stock bike? thanks for the help!!

[Braff1]

RIKR4X,
I had near the same problem when I was trying to rejet my 300 EX. It seemed that no matter what jet size I ran the plug would be white. I did some research and found that some gasoline formula's contain additives that will give you a false reading of your engine running lean (this was my case). I found a post by Ogre on how to rejet your quad, I tried it and have not had a problem since then. When I recently added a few mods to my 400 EX I used Ogre's method again and it runs beautifully. I find it amazing as I read through people's post and find that I ended up using the same jet size for the same mods. Here is a copy of Ogre's post on how to rejet. I hope this helpsYou will see the light
Jetting can be very difficult given the way you're approaching it. Plug reading has become unreliable given newer gas additives and longer life plugs.

Another (and safer) way to jet your machine is to "over-jet" it. The point is to make your machine run too rich - it'll give you a reference point.

First, you have to test if your machine is already running rich (with the 180 in it).

Put the machine in 2nd gear, get rolling enough so the machine isn't quite lugging, then roll on the throttle. Hold it wide open til it either (A) skips, blubbers, cuts out (can't miss it) OR (B) you've reached the top of the revs without the above symtoms occuring.

If you get A, then you're too rich on the main.

Else, if you get B, then run to your dealership and pick up a 182, 185, 188, 190. Retest with the 190 in. If you get A, drop to a 188 and retest.

Continue to do this until you achieve B. Then, drop back one more - you should be perfect then.

If 190 isn't high enough, go get more!

Although 180 does appear a bit high, only YOUR machine knows what it wants.

This is basically a fail-safe method, you will see results.

What to do with all the extra jets? Just return them, most dealers are happy to take back the unneeded sizes. Or if you're like me, you'll keep em, never know when the next engine mod will come along!

I've performed this jetting technique countless times - it is much easier and more effective. Plus, you won't have to burn your fingers trying to get the darn plug out!


Hope this helps,
ogre

[RIKR4X]

are you saying i might not be to rich? you dont think going up from 170 is way to much? should i ddrop my pilot to a 40? is there a point were im going to hurt my motor by to rich? i guess every bike cant be the same , but it sure seems like alot of people arnt over 160 , there is one thing i just remembered the pilot i put in was longer than the stock,would that do anything? thanks again

[oynot400]

To color the insulator on the plug takes time. I went through the same headaches you are going through now. I was reading the plug white after each run. By the time it was colored the way I wanted it was way too rich.
For a quicker plug reading look at the electorde. There will be a white residue on it. The longer the residue strip the leaner it is. You want something about 1/8 inch strip.
Hope this helps...:)

[beerock]

id like to know what kind of gas your running. sounds like additives
to me

[Wheelie]

If the initial throttle feels good, leave the 42pj in. Your main circuit is DEFINITELY too rich. Leave your airbox lid off, it will run a lot better.

My 400ex is hands down faster than it was when it was stock.:)

When it comes to your question about the main circuit, try my earlier suggestion. I think you will surprised with the results.:)

A 155 or 158mj will hit the 'sweet spot'......Trust me, try it. Put the 155 in, run it for 30min or better, then drag race your buddy.

BTW---IMHO---In My Honest Opinion.
BTW--By The Way---The 40 and 42 pilot jets are longer than stock, this is normal.

Good Luck,
Jeremiah

[RIKR4X]

Ii just put in a 190 (crazy!!) it seemed slower ! too rich i guess but it didt cut out and i did a plug reading and it was white!!! this is driving me to put back on my stock exhaust. i run amocco premium 93 always fresh. so you say leave lid off try 155, thats what ill do,thanks for the help

[Wheelie]

Leave your E-Series on your quad....it has nothing to do with your plug reading. You paid good money for that pipe, a good pipe I might add.

Try the 155 and don't try to read the plug anymore, it can give false readings.

[beerock]

The GAS you are using is giving false readings, I know amocco uses additives in thier gas. switch gas, check your plug again.

the gas is making the plug white.

If you want to jet your bike correctly you need to read the plug.

[RIKR4X]

I just took 6 disk out put the 155 back in and put my lid back on, it sure felt like it pulled harder on the top but lost a little low. does this make since? Is it ok to leave the filter skin on?

[tinner]

When I first started doing mods to mine I started with an FMF MegaMax (with all the discs in),K&N filter/Outerwear with the lid on and I ran a 158 and stock pilot. Reading the plug is kinda tough with the reformulated fuel here in the Milwaukee area. What I've ended up doing is test running some jets especially after the piston. Start richer than you expect it to run and work your way down. I think I had a 162 down to a 158 and 162 was to much bog for my setup at the time. Good luck

[RIKR4X]

I just added 2 more disk (8) that seemed to bring my low end back and have pull on top. I guess the real test will be when my friend will be left behind!! Has anyone ever messed with their disk?does this sound like an ok combo?

[Wheelie]

It's a good idea to leave you filter skin on, especially if you run your quad with the airbox lid off......which I would highly recommend you do.

Remove your airbox lid, bump the disc# back to 12, leave your jetting as is, turn your mixture screw out two turns.......then ride like hell!