KDXRIDER.NET

Looking to have a thread that matches the subject....

Where's your bike sit...jet-wise?

Some of the responses to your plug questions on that other site weren't right.

The pics of your plugs (plug chop having been done correctly) in the gallery are pretty darn rich.

What did you start with, needle-wise? Generally speaking you are finding the 'g' direction in diameter to be better than the 'k's? That does seem a bit odd to me.

Oh...get that airscrew out! Well, at least try it. I think that's been discussed already.... Have you been out to 2 1/2, bracket that setting up to 1/4 turn by 1/16ths and STILL prefer 1/4 out?

Can't say as I believe that, either.......

OK CC...It does make sense to start a new thread rather than horn in on someone elses. Especially since this saga is spread out over two websites and three different threads.
Lets start from the begining. I decided to mod the hell out of my stock 03' 220R. I sent my cylinder and head to FRP for porting and head shaving. Carb to RB Designs. Bought an FMF rev and turbine core 2. Wiseco piston. Delta Force 2 reed valve. Uni air filter. and pulled the air box lid off. I put it all together at one time.

HUGE mistake.

The bike was pure hell to start, wouldn't idle, and once it was running "if" I could get it to start I had to pump the throttle to get it rolling and then once it was rolling along it had about the same power as stock.
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Hysterectomy advice

YIKES! Hard lesson learned eh? One mod at a time my friend... one mod at a time.

Was the RB done for a port and shave? Did Ron know what you were doing? Ron seems pretty consistent but I think there is no consistency to the FRP porting from what I have seen and that would be a nightmare in itself. Need to get back to basics but it is hard if all you have is modded parts. I guess your plug is all you have to go on.... but I would start with getting it to start well first, since you need to do that to do anything else! Since you are ported and shaved, I would start with some high octane fuel just to get the ball rolling. Hard telling if any baseline settings would help your situation but I doubt it. I hope we can help you get this sorted out but it sounds like a long road to Zen! CC will probably be your best source for the info you need since he has most of what you have but in the 200 form.

I immediately checked all the basics. The bike parts were functioning fine. I started to work on the jetting. And found out I suck at it. So I've been reading huge amounts of web content and various threads. I now feel like I have a pretty decent grasp of how the individual jets work and how they work together for the final result.
Unfortunately right about the time I was rounding the corner the great DRN abandonment began and I was stuck listening to a bunch of guys who were just as cluless as I was. And in some cases even more so.

The stock carb was set up with a 42 pilot - 1173 needle - 5 slide- 145 main and it ran good when every thing was stock.
The carb was returned to me after the RB mod with the following set-up. 40 pilot - CEK/3 - and 150 main. AS@7/8
(extra jets supplied are 38,42 pilots CEL needle and 148,152,155 mains)
I know this set up has worked great for a lot of people but I think that it may not agree with FRP porting.

I went through a tremendous amount of pilot jetting and AS sessions and never got the bottom of the RPM band to act right. I've used pilots from 38 all the way up to 52 and it always acted better with bigger pilots, and the air screw kept demanding that it was set to near shut. Problem was the plug always looked stupid rich.

So I started slimming down the needle tapers. and alas it started acting right. I finally started to get some transition from 1/8 to 1/2 throttle. Each time I put in a slimmer needle it got better.

Many many jet sessions later I'm at 42 pilot and 1/2 out on the air screw. Needle is @ CEG-4. Main at 155 I think it may have been a touch better at CEG-3 and 150 main but I "thought" the plug was reading lean

I still have a touch of bog on the bottom when hitting the throttle but it's much better now. I had good seat of the pants results at CEG/3 and 150 main but it scared me because there was nearly no exhaust smoke. I was afraid of seizing and again I "thought" the plug was reading lean. I apparently thought wrong.

To compound my confusion I've been getting what I have found to be really dumbass advice on how to jet and how to read a plug. I now know that my local "pro" shop mechanic is NOT a pro. "The tip should be tan etc." So seeing white insulator had me thinking lean.
I have looked high and low for pictures on the web of various plugs and their meanings with no luck. Other than this is a plug with melted piston on it this is one that got smacked by the piston this is one that burnt the electrode off this is one that blew the insulator etc. Absolutely useless unless I want to know how I blew my stuff up.
Thankfully you'all have shown me the light on what a correct plug is supposed to look like. Bad plugs and why would be a help too. Lean plug, wrong heat range, etc.
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YAMAHA MAXIM XJ750 SPECIFICATIONS

Indawoods wrote:Was the RB done for a port and shave? Did Ron know what you were doing? .

Yes he (Ron) specifically asks if the carb will be put on a ported cylinder. I sent him a written list of all the mods and mention of FRP porting and headwork were mentioned.
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Human papillomavirus (hpv) advice

Dang if it doesn't sound like you got an air leak somewhere. Keep in mind, all my KDX220 advice is without the FRP porting. Man, I am so glad that I can learn from you guys. Not just what works but what doesn't as well. With that said, here is a recap of my bike mods and performance for your comparison:
1999 KDX220, Wiseco Piston, RB Modded Air Stryker carb jetted as: Pilot:38 Air Screw: exactly 1 turn out, Needle: CEK #3clip position(just moved up from #1clip position, Main 145 (just moved up from a 143), Head reshaped by RB Designs for use with race gas AND high altitude riding, VForce III reed system(just changed from origional VForce reed system), FMF woods pipe, TurbineCore II Spark Arrester, FRP torque ring.

Other items that may or may not have any bearing:

Steahly Flywheel weight, Iridium spark plug, air filter lid removed, No Toil air filter and oil, 12 tooth counter shaft sprocket.

So, besides porting, you have a modified origonal carb. Your jetting shows rich based on the plug reading for a WOT and the photos you uploaded, but a lack of ash in the exhaust and what feels like a lean bog has you concerned with causing damage. Here's the thing on lean seize: YOur bike will give you plenty of notice if you're getting into dangerous territory. It will sound bad. If you are moving in small increments with the jetting, and then only doing WOT plug chops at that, then you won't damage the motor. As you probably know, you have GOT to get the main right first. It helps if the bike can idle but I don't think that is as critical. With the arsonal of main jets you have on hand, and 5 or 6 new plugs, you should be able to find the right main jet in a single session. Before you start your quest for the correct main jet, please be sure the floats are set correctly and that the float needle is working right. Verify fuel flows freely and shuts off fully with the float and needle. It's messy but I think necessary in your situation. YOur next step would be to get a needle that works. I would recommend going back to the RB initial needle and clip position and start there. Start testing with the clip at the #3 (middle position) then try both the #1 and the #5 positions just so you can feel what the differences are. Remember to only evaluate the throttle position that is affecting the needle jet circuit. In other words, at this point you aren't really looking to the 1/8 throttle position nor the full throttle position. Just that area (1/4-3/4) of the throttle where the needle has it's most affect. REMEMBER!!!! the throttle position and engine rpms are two different things. The bike needs to work well at a specific throttle position regardless of engine rpms. For example if half throttle is bogging the motor at low rpms but rips at high rpms, then that isn't the correct needle setting. (My bike did this. I was lean by 2 clips on the needle) If that needle turns out to not work right, then move to another needle based on which clip position felt the best on the CEK. This might entail a needle that is just leaner or richer overall or it might mean swapping to a needle with a completely different profile. You may be noticing that I am not mentioning plug readings at this juncture. Mainly because I think the seat of your pants is best at this point. This is going to be potentially the hardest part since it sounds like the CEK isn't going to do the job you want it to. The testing is needed though in order to establish a foundation of performance and to determine which way you need to go in order to get the performace the bike is capable of and you expect. Finally, once you have the needle down, the pilot remains. This will also affect the pilot air screw setting and will make a felt difference in the !/8 - 1/4 throttle performance.

If you have read this far, that's great! I think where you have been making a mistake in your jetting attempts is that you don't have the correct main jet yet. Your statement earlier in this thread;

" I went through a tremendous amount of pilot jetting and AS sessions and never got the bottom of the RPM band to act right. I've used pilots from 38 all the way up to 52 and it always acted better with bigger pilots, and the air screw kept demanding that it was set to near shut. Problem was the plug always looked stupid rich. "

reveals that you are not jetting in what most concider the correct sequence of jetting; starting with the main and working down. If the plug is looking "stupid rich" (I love that term!), then deal with that first.

Always and I do mean always start each jetting session with a used plug to warm up the motor. Never jet with a cold motor. I know that it isn't easy to warm up a motor in a suburban neighborhood but unless that bike is heated up just like you would in an actual riding situation, I'm not sure jetting is going to be relevent to your trail riding. (Is that clear or does that sound as muddy as I think it does?) What I am trying to say is that starting the bike, letting it idle for several minutes, fanning the throttle, then shutting down to put in a fresh plug for a WOT plug chop reading may not work. I believe you need to ride the bike and but load on the motor and have it at full operating temperatures, engine, transmission, clutch, etc, before any jetting performance can be evalutated as to it's effect.

You are going to get this figured out BJH, just hang in there.
All my opinions and recommendations are based on my own personal experiances and not regurgitated from anything I heard anyplace else.
O.K. let's here from the experts where I'm wrong. I'm sure there's something I got bass asswards

Thanks for the information Ski. I have some time off for the holidays and I will get back at it. Starting from the top down does make sense I guess since I'm having the most luck at the higher throttle range.
I'm fairly certain I can get the main correct since I now have examples (pictures) of what a correctly jetted plug looks like. That has been a huge missing link. If anyone else has photos of plugs both wrong and right PLEASE post them or e-mail them to me. I really appreciate the help guys. I would be lost, very lost, without it. A section somewhere in this forum dedicated to jetting WITH plug pictures would be a great benefit to those of us that don't habla jetting. I have read articles until I'm blue in the face but if I can't read a plug it's a major hinderance.
Thanks again guys and keep it coming,
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Cl450

That last photo in my gallery of the plug with milage on it shows how the dark band can be a pencil line, not just at WOT but at all throttle positions. Keep that image, minus the crud on the insulator, in your mind as to what the dark band should look like. As in the other two photos,, 145 main and 150 main, they clearly demonstrate that a couple of jet sizes do make a large difference. Again, I think in the photo that the 145 is still too fat. I changed to a 143 but didn't take any photos. I will see if I can find that plug and put up a photo of it.
My personal recent jetting problems have be back with the 145 main, up from the 143 and I believe that is due to the colder air temps now; as my origonal jetting was during the summer. That's certainly something to keep in mind: current conditions. When jetting be sure and try to get to it all in one session. A change in weather might affect results and have you scratching your head in confusion. As you probably know, I did all my jetting using VP C-12 fuel. Mainly because I eliminated one big variable out there that most others will just ignore. That is: fuel from the gas station is constantly changing, constantly being reformulated, no way of telling the age, heck, if the same hose is being used for the various grades at that pump, you are at least getting a hose full of regular when you are maybe only buying at most, 5 gallons of premium. You said your head was modified by FRP. I would seriously consider performing the jetting with a race fuel if for no other reason than to eliminate that variable. But even more than that, I would consider sending that head over to Ron at RB Designs, telling him the history, (I think you already have) and asking if he can help you get the head back into shape. Let him know that we talked about this and that the work he did on my head works great. Feedback to the guy doing the shaping is invaluable to improving with generational changes.
I wonder if it is possible to contact FRP and request that he exchange barrels with you for one that has not been modified. He may have some stock on hand or he may just receive yours, and someone else who is requesting porting work, then swap. It's worth a shot.

Kin I butt in?

re: Main jet first

While that is my preference, that isn't always the choice. Some tuners that certainly know what they are doing start from the bottom and go up. Personally (please...consider the source!!) I've found that an incorrect main WILL have an effect on idle. I have not found an incorrect pilot to have an effect on WOT. So...from top to bottom makes much more sense to me.

Bottom to top will get the job done, but I'll bet you will be making a few loops through that course of action to get it right.

I said this in one of the other threads...but a repeat for this thread: Your porting is absolutely a culprit in this situation. I'm sure yours is because I know mine is. While yours is a 220 and mine a 200, I found porting (FRP in both cases..I'd bet that anyone else's port work would have a similar effect though) to come with a major jetting headache. I'm not 'there' yet with my bike. I am to a point that it runs very well and want to just RIDE for awhile before I get back into a bunch of jet-dinking.

Something to keep in mind: Spooge is not always the result of over-rich jetting. Ski made a comment recently about C12/temperature/vaporization that is probably relevant to this (I think). In my case, a perfectly tuned and running bike (exhaust looked like a 4-stroke) went completely south after my port job. The bike pinged like crazy (lean?) and spooged like a leaking faucet (rich?). Shortly after putting the ported cylinder on I seized the thing..and that was @ 4000'el. Really??? A weeping spooging mess AND a lean roll seize? I went up two mains (three up was a loser) to get to the best seat-of-the-pants effect I could.

Guess what was greatly reduced. Go ahead...just guess! Spooge.

Yep! Two steps up in main jet size and much less spooge as a result.

I am curious about the lean direction you're heading in with needles. A CEJ is considerably richer than the 1173 that the 220 came with, but considerably more lean than most 220s take. I don't have my needle chart at hand...but the 1173 is somewhere around an xxP. Now...keep in mind that you're only talking about a couple of .0001's of an inch between those two (J and P)! It's not a matter of a 'huge' difference in diameter.

The RB carb is a factor in this deal, too. These carbs started out with AEN needles. Wow! Was THAT ever a mess. If you idled more than a minute you would end up with a 4-stroke blubbering mess that you might not be able to recover from. It was a long time and a lot of messing (JD was a huge help in this) before the sharper slopes were tried out and found to be key in correct RB-modified carb jetting.

I 'spose I could find it if I read thru my stuff for the next couple of days...but I recall JD making a point regarding diameter, its relationship to proper transistion to slope/clip throttle points. Going richer on the straight section (again...not necessarily L1..but straight...running that straight section longer due to the increased slope (make the slope 'hit' later in the throttle) was a big deal!

A digression please?

Seeing as we're talking about needles and I haven't said this for the 34th time yet today...here 'ya go. I think it is critical when it comes to understanding needle psychology.

You must keep in mind how slope angles effect L1. For starters, L1 is commonly referred to as the 'straight' section of the needle. That ain't Hertz..meaing, 'not exactly.' The L1 measurement is taken from the blunt (clip) end of the needle to the point on the needle that the diameter is 2.515mm. It doesn't matter how fat, how skinny or what slope...the 'magic number' is always the same...2.515mm. So...you can deduce from that fact the following: The more slope (sharper angle/higher number..progressing with A, B, C, and D designations) a needle has, the later the taper actually starts on a needle. A sharper slope will narrow faster, so it starts later on the needle to get to 2.515 given the same L1 number.

Compare, say, a CEK to a DEK. C=1.50º taper, D=1.75º taper. Although the L1 in both needles is the same the 'D' needle will have its untapered (straight) part of itself in the needle jet longer (more throttle twist) than the 'C' needle will. Comparing those two needles in this one circumstance the 'D' will be more lean further up the throttle range than the 'C' will.

Anyway...I've been though that only about a gazillion times and may well bore everyone to tears with it. BUT...understanding the connection between º of taper and L1 is critical (imo). I used to think L1, commonly called the 'straight section diameter' was just that! ...the length of the needle that was 'straight'! After all...that IS what you call it!!

But...alas and alack...that is not spoken with veracity, truthfulness, honor and character. IT'S A BIG FAT LIE!!

...so there. ;)

BJH: Your comments regarding seat-of-the-pants response, your 'jetting arsenal' on hand and your determination in keeping after this convince me that you will get where you should be. Keep at it! A properly tuned bike is the biggest 'bang for the buck' you can get. Besides, it will hold you in good stead no matter WHAT you're riding. Commendations on your progression to this point!


Ski: Looking at your plug pics...you still look big on the WOT side of things. Yeah..the 100 mile plug is pretty! Nice little ring at the bottom of the plug (how close to 1mm is that?) Certainly that wasn't 100 miles of WOT, but a mix of this and that..idle to 1/2 to 1/4 to downhill to etc. etc. While you might say that 'overall' your jetting looks great...carbs don't ever work 'overall'. They work in discrete throttle ranges that are changing all the time. The old saw about someone with their feet in an oven and their head in a freezer?...the average may be 'perfect'...but someone's gonna be dead in that scenario before too long. Averages can be very misleading when taken to mean anything other than exactly what they are...likely a mystical figure that has no basis in the real world.

But...you know all that.

...I think that's 'bass ackwards' ain't it? Other than that..I (may be a has-been...may be a drip under pressure...but not an 'expert'!) I liked everything you said!!

...especially this part: 'My bike did this. I was lean by 2 clips on the needle.'

I really Really REally liked that part!!!

Cheers!

Merry Christmas, too!

No 'season's greetings' or 'happy holidays' It's CHRISTmas fer crin' out loud. If that bothers you...get over it.

Ski! You snuck in on my long windage.

A 143? Wow. Is that a custom-made jet?

re: modified FRP heads

It is my understanding that he doesn't modify much of anything in regard to the head. In my case, I sent my head in with the cylinder so it could be 'matched' to whatever he did TO the cylinder. It came back with virtually nothing done to it. Maybe ensured to be flat...but not any reconfiguration done.

Ron will do that for you. I sent my head up to Ron in an attempt to resolve some of the problems I had after porting. It helped! You might consider that, too, BJ. Keep in mind that increased compression will improve bottom at the expense of top. That is a VERY generalized statement. The squish band is nothing but a huge magical instrument when it comes to flame fronts, propigation, detonation...everything that happens in the cylinder when it goes B-U-R-N. Ron changes that...AND fixes the problem common in all kdx heads...the volume between heads varies considerably.

HEY! I want to know that you (BJ) have bracketed the air screw in the ranges I mentioned earlier. Yes? No? If you have...do it again when you get your other jets sorted out. Tell me it don't work better out there!! Of course...then I'll have to call you some names...but go ahead! Tell me it ain't so!! ;)

I guess it's a 142 then. I can't count by 2's then 3's then back to 2's again. Anyway, the one jet size smaller than 145. (geez!)
Some day I'll try the AS out there just as some day I'll try the DEK needle. You are so dam adamant about it that it's more fun at this stage to listen to you rant on (yes, rant!) than to admit you are right. (probably, I don't KNOW yet so I don't have to say one way or the other....at least that's my story and I'm sticking to it!).

[quote="canyncarvr"]Kin I butt in?
Please do!!!
re: Main jet first

CC -I've found that an incorrect main WILL have an effect on idle. I have not found an incorrect pilot to have an effect on WOT. So...from top to bottom makes much more sense to me.

BJH-This is new knowledge to me and it makes sense. I'm going to start a new session with getting the main done right first. I've been paying little to no attention to the main because the problem was in the low throttle section.

CC - I said this in one of the other threads...but a repeat for this thread: Your porting is absolutely a culprit in this situation.
BJH - I agree. My thinking is that while porting allows higher fuel / air flow volume it lowers the velocity / force of the intake charge. Much the same with car engines. smaller intake ports on the head and smaller valves make more low end power but larger intake ports and valves and cam lobes are needed for high RPM drag racing. That's why drag engines lope so much at idle. Weak vacuum signal on the intake.
(yes/no/maybe?)

CC - Something to keep in mind: Spooge is not always the result of over-rich jetting.
BJH - I tend to agree. I had a smoky liquid creosode type spatter coming out of the silencer even though the bike "felt" lean on the bottom. So much in fact I think it may be wise for me to repack my brand new silencer. The spooge even made a spatter mess on my rear fender.

CC - I'am curious about the lean direction you're heading in with needles. A CEJ is considerably richer than the 1173 that the 220 came with, but considerably more lean than most 220s take.
BJH - I'm somewhat confused here...I have kept the L1 and taper the same throughout my jetting trials. I have reduced diameters to assist in the low throttle position richer from the RB shipped CEK 2.695 dia.to CEJ 2.685 dia. then CEG 2.665 dia.

I read and believe I understand your words of wisdom on the tapers. I will fiddle with that part soon. I'm very anxious to try the D profiles. But first I want to get it running "right" so that I can form a good baseline to make proper notes from that point. ala fine tune jetting for my powerband likings.
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Post-Traumatic Stress Disorder Forums

If anyone else has photos of plugs both wrong and right PLEASE post them or e-mail them to me.

Here's a thread or two re: the subject, w/pics:

URLplugs wpics

URLmore plugs

(Someday I'll figure out how to get rid of the "URL"!)

Hmmm...did I just make some kind of faux pas by linking to "that other site"??

Do I have to do 50 push-ups now??!

I think we up'd that to 100!

I vote we ban him!!! He's obviously a troll, trying to get everyone fired up.
Actually I really enjoyed reading that first thread again. Great photos of plugs there for sure!! Thanks for the link j!

Actually I think we should have rights to the archived intellectual property deposited on that stain.
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American dad! forums

re: (geez), rant, counting by twos etc.

Me'n Rodney. Don't get no respect.


But...I don't know that he didn't deserve any either! ;)

FTR: When it comes to dripping spoo and being lean, I am not referring to a silencer that needs to be repacked. Yes, a gooey silencer will blow spoo no matter HOW lean you are (for awhile..then K-A-B-L-O-O-E-Y). In my situation the silencer had been freshly repacked.

CC...Ok I'm still a bit confused. I've been using the graph available on C Daves' site to judge where the changes need to be made (Ishould probably do this sober but it's Christmas with my family and I'm quite buzzed)
When it comes to the needle the chart only shows evfectivness at lower RPMs with the needle taper. Therefore I hav been slimming th eneedle down to add some throttle response down low. I haven't messed with the tapers and L1 yet.
Ah the hell with it. It's Christmas and I will continue this further when I'm sober and can think straight. In the mean time MERY CHRISTMAS to all of you and thanks for the help. btw I got some new Renthals I hope each and every one of you are enjoying your Christmas.
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Vaporizer reviews

What's the confusion part, exactly?

The chart on CDave's site is fine....as long as you keep in mind that it's not a jetting genie on a chart.

Re: throttle response down low

I guarantee I could screw up your off-idle response with:

A 'bad' (wrong selection):

1. Main jet
2. Needle
3. Air screw adjustment
4. Throttle valve

I've been through (at least) all that.

If you're chasing off-idle or low throttle position response with only the needle diameter, you may well never get it sorted out.

You mention a couple things that are problematic:
1. Off idle bog (however slight) and
2. Air screw settings that aren't right (almost closed).

Don't know about air leak...but ski thinks so..and I do wonder. I'm tending toward the idea that something else is causing your problem..and jetting changes are merely masking that...or trying to. But then...I also wonder about the porting part. I'm 'off' some on my jetting right now and I KNOW it's the porting that's giving me fits (said that already).

I think I have a CEJ..maybe a CEG, too. I have absolutely no complaint about how the bike is running...off-idle response is perfect, low throttle ranges in 2nd/3rd gear is where I am most of the time. The only time I need 1st gear is when I've been too chicken to gas-it in 2nd when I should have (which is usually just a few yards before I'm jamming for 1st ;( ). I'll try a couple of smaller diameter needles to see what happens.

Still I'm sure my little green scooter hasn't stopped amazing me, yet.

OH...I've said this already,too..but TELL ME you know about the throttle cable nylon retainer tab and how it fits into the needle retainer nut. Tell me you ensure at every needle change the fit between these two pieces is correct!

This is 'fer sure. A bike that needs an 'almost closed' air screw...ESPECIALLY on one of Ron's carbs is wrong! I keep harping on the #2 sweet spot..and most keep ignoring me. Maybe it's only the 2-hunny that likes it. I don't know. Look for it. Find it and you will be amazed (maybe yet again) at its effect. If the 220 doesn't show it, at least you will know.

Cheers!