Question - plug and jetting

[santod]

I am the 3rd owner of a 1997 KDX 200. I have rode the bike for about 7 months now. The bike runs strong and functions great. I have never fouled a plug and the plug has a nice color to it. I do have a complaint about the amount of fuel the bike requires which might suggest rich jetting.

I am to the point where I like to make some of the standard upgrades. The bike came with a FMF fatty pipe and silencer. Last night I added a rad valve (got it for cheap from a friend, I know the power reed work just as good and the delta valve is better).

As stated everywhere leaner jetting is required for the rad valve. I am trying to get a baseline on how the bike is setup before ordering new jets. So here the current setup:

plug = b7es
main jet = 160
pilot jet = 45

the plug is good color but the bike used a ton of gas. None to little spooge is present.

Question time finally:

The 45 pilot cannot be the stock jet right?
Why is the plug the correct color yet the main jet so large? Is the extra heat of the b7es creating enough heat to prevent wet fouling?

Thanks in advance I like to understand what is going on before jetting down and returning to the correct plug heat range.

 

[canyncarvr]

I think you have resolved this already?

Check CDave's site here to get a head start on jetting.

Plug color doesn't tell you anything about jetting.

Using the wrong heat range plug to 'fix' a jetting problem is an error, but that is part of why your 160 main gives you the color you're seeing.

The 45 pilot is not stock. It's one-lean, actually.

Don't know what a 'ton' of fuel is...but 45/160 is too rich for most situations. It won't make the difference between a 'ton' and a 'correct' amount of fuel, though.

I'd guess your bike is peeing when you're not looking! ;) Now..usually that's a good thing (not looking that is). Commonly, the KDX will piddle a good bit. Kickstands are often tweaked (bike leans a lot) and the spec'd float level is a tad high. Combine that with a lot of bikes having a less than stellar float needle/seat condition (not stored properly)..and you have leakage.

Does your bike leak?

Maybe it Depends? hardy har har.... ;)

 

[steve.emma]

plug colour DOES tell you a lot about jetting, that is common knowledge. aside from riding the bike its the best way to determine jetting, (a dyno would be the best way but there you go...). BTW not just my opinion here, read any guide on jetting to get the same answer.

 

[Jamir]

Plug color doesn't tell you anything about jetting.

this is why folks should read this site a bit and get a feel for who the experts are. Then listen to them. I would love to see Rich bite this one.

 

[steve.emma]

yeah lol, im guesing what he meant was that unless you know what you are doing plug colour doesnt tell you anything about jetting. most of us with some experience know how confusing plug reading can be if you dont know how various carb circuits at different throttle openings affect mixture strength and therefore plug colour.

 

[m0rie]

I'll bite. With premix the color at the tip of the plug varies depending on the fuel and premix used. It doesn't tend to be consistant. The band at the base of the insulator is consistant and it is what should be looked at for jetting purposes. The long thread by Rich in the archives does a good job showing how to jet the main by using the mixture ring that forms on the base of the insulator.

 

[Rhodester]

Santod, as I stated elsewhere, the reason your jetting seems in the ball park is because you're running around at temperatures around freezing outside. If it were 70+ degrees it would be a different story. BTW, Canyncarvr and mOrie have a high level of expertise on this subject.

 

[santod]

I have installed the RAD Valve and went to a 42/155 setup. Here in Atlanta, Ga the in the winter can change from 40F to 70F in no time. I have discovered I am a bit lean (1/2 throttle)in the needle on cold days and always rich in the pilot no matter the temp or air screw setting. I just ordered a 40 pilot seeing that come summer it will be 80 ot 90+ riding conditions. I will try this setup before going to a different needle.

 

[Dewster]

I'm running a FMF pipe and silencer as well with the little air box mod. I can get about 45 miles to a tank before I need to switch to reservere. I'll check my notes tonight to see which jets I'm running, I know I changed them... just can't remember which. :coocoo:

 

[John Harris]

Santod, I have recently added a pipe and Boysden reeds and cold weather. My latitude is about the same as yours, with temperatures just as variable. I was running 40 pilot before the changes, but it is too lean now and I had to go to 42 pilot. It is just barely rich enough with the cold weather! Cheers John

 

[canyncarvr]

plug colour DOES tell you a lot about jetting, that is common knowledge. aside from riding the bike its the best way to determine jetting, (a dyno would be the best way but there you go...). BTW not just my opinion here, read any guide on jetting to get the same answer.

Please do let us know where to find such 'any guide' so we can all get 'the same answer.'

I can't wait to become informed.

..this is why folks should read this site a bit and get a feel for who the experts are.

Can't say as I have a clue what this means. But...hey!!...not having a clue is evidently what I do best.

Take out your '8' plug with a good lot of that telling 'color' on it. Put in a '6'. Run THAT with the exact same jetting and environs.

Of course, the two will look exactly the same because the jetting hasn't changed and the color DOES tell you what you need to know about jetting.

An old saw..but, 'The next time I am passed by a dyno is when I'll start worrying about what it tells me about jetting my bike!'

Cheers! :bang:

 

[NM_KDX200]

'The next time I am passed by a dyno.....

Happens to me all the time.

:)

 

[Rhodester]

CC, I thought I was going to die laughing over that dyno remark!!

Is it not true that dynos are only used to measure power at various RPMs at FULL THROTTLE? If that is indeed the case then other partial throttle and load conditions would be excluded from any testing results. It might be useful for main jet purposes, but in the real world a main jet selection for the most WOT power would be right on the edge of a lean condition and would put one at risk of seizure. Just a thought.

 

[canyncarvr]

You can do an idle dyno run if'n you want to.

Regardless of the throttle position you choose, dynos miss a couple of things here'n there, though. Slow (and believe it or not) hi-speed suspension movements, mud, rocks, loops, downhills and (another believe it or not) 1/2" of wet (thawed) snot on top of 6" of frozen clay!

Power is worth diddle if it doesn't make it to the ground. The best measure of that (in my case)..of throttle response, smoothness of delivery, tune-time of the 2-smoke effect..in every case it's my own derriere.

Doesn't mean anyone else has to like it! ;)

I could check the color.............:yikes:

 

[G. Gearloose]

this is why folks should read this site a bit and get a feel for who the experts are. Then listen to them. I would love to see Rich bite this one.

More accurately, if folks would ever begin to read old posts they would stop asking daffy noob jetting and spooge questions because they have been answered adnausium both proficiently and patiently by CC for years, as well as being instrumental to refining the RB carb mod with the expertise of fishhead and james dean. CC has gone far beyond the call to enlighten other KDXers well beyond where others had tired.

It has been at least 2-3 years since a new, unique jetting question has been asked on this board. Most of the 'good stuff' is older still.

CC is an asset to other KDXers with both humor and expertise, best try not to screw it up for everyone else.

Jet by plug color.. how quaint and simple...wish I thought of it.

 

[steve.emma]

you are right that people should read old posts etc and stop with the daft questions. but for someone with such knowledge of jetting and bikes to make a blanket statement that plug colour doesnt tell you anything about jetting only serves to confuse the person asking the question. you ask what jetting guides i refer to? well there are many links to these guides around on DRN maybe you should check some old posts or sticky links sometime..... but as an example the justKDX website has a jetting guide that uses plug colour as an indication and Eric Gorr's site and books have articles on reading plugs in reference to jetting and mechanical problems. i agree it doesnt tell you everything about the air/fuel mixture you're running but its a pretty good start.
my remark about the dyno is true (we are talking about jetting here not riding), i agree that its not cheap and not very availaible/practical to everyone and doesnt take into account for traction etc.. but i was just making the point.

gearloose you say how quaint and simple, but to a newbie asking a question on this board the simple answers are often the best.

sarcasm however is the worst form of humour.

 

[canyncarvr]

OK. No sarcasm, then. Whatever you wish to call it, the facts have passed you by.

I stated it plainly the first time. I don't know if you thought that was me being funny or trying to be a smart aleck.

The following is not meant to be nasty, mean-spirited or cantankerous in any way. If you can't stand the facts, stay out of the kitchen.

...to make a blanket statement that plug colour doesnt tell you anything about jetting only serves to confuse the person asking the question.

The referred to 'blanket statement' is true. There should be NO confusion to any person asking a question regarding plug color and jetting having been told or having read: 'Plug color doesn't tell you anything about jetting.'

Telling Gearloose to:

..you should check some old posts or sticky links sometime.....

..I'm afraid points you out to be ignorant about the entire subject. Nothing wrong with being ignorant when it is rectified with the facts. If you do not want to listen to the facts, then ignorance is clearly the underpinnings of stupidity. There IS something wrong with that when it's merely bullheaded opinionated foolishness.

Indeed there are many threads pointing out exactly what I said..plug color tells you nothing about jetting.

Indeed there ARE threads that have the same old question asked again for the gazillion-eth time that maybe have been ignored..because they have been asked a gazillion times! Them being ignored (not corrected) doesn't make them correct.

Indeed, Mr. Rohrich has been around this subject time and time again...complete with 8 x 10 glossy color photographs with circles and arrows etc. etc. that pointedly show that ...what? All together now:

Plug color does not tell you anything about jetting!

Please do read this:
http://www.dirtrider.net/forums3/showthread.php?s=&threadid=48348

**Unfortunately...the pics have been removed from that thread. They may be elsewhere. I don't know about that. The text still should be helpful to you.**

When you're done, you will know that...what? ...Plug color does not tell you anything about jetting.

If, perchance, after reading the above you do STILL have the opinion that it DOES have something to do with... I am afraid you are hopeless.

Now...it does occur to me that 'plug color' to you means something completely different than 'plug color' does to everyone else. That possibility has also been covered in this thread from the beginning (m0rie).

Again, lest you (or anyone else reading this) misunderstand: The point of this is not to ridicule or point fingers and snicker at you. You persist in thinking incorrectly and DO attempt to make fun of those with the correct understanding. The point is to allow you the opportunity to also understand correctly, in words stated as clearly as possible.

Please do ask any pertinent question that you may still have.

BTW..Please note that I did NOT say, 'Plug color means nothing.' Of course it DOES tell you a lot about 'stuff'...just not jetting.

Cheers!

Sir: So much for kudos, 'eh? Thanks!

 

[StuckinJersey]

I was riding last weekend freaking Dyno ran me right off the trail. Hate those things.

 

[m0rie]

This is the link the CC was referencing, complete with pics:

http://www.dirtrider.net/forums3/showthread.php?t=60392&page=1&pp=20

 

[canyncarvr]

Thank you, m0rie!

There's been a problem with that thread for about ever..I need to update my link list with the picture thread.

Thank you for the illumination!

Actually...try this one, too:

http://dirtrider.net/forums3/showthread.php?t=60392&page=2&pp=10&highlight=jetting+fast

:nod:

Well...the two looked different the first time. Same thing. One from a search..one not.

I never SAID I wasn't stoopid! ;)