Jetting Needles- Urghhhhh

[RJ-KDX]

I am having some jetting issues. I have read CDave's info on jetting and understanding jet needles, Gorr's on carb tuning, some of RR's posts, and I still can't make sense of it.

I'm running a '01 220 w/ a 35, TC2, ab mods, BR8ES, #145, #40, R1173L 2nd clip from top, as 1.5 out, Amsoil S2000@ 50:1, Shell 100 octane. Plug is dark brown, and I've cut the shell away and have a carbon ring about .125" thick from the base up.

I think I am running rich, from the plug condition and the line of oil running down the silencer. If I lean the needle I'll be on top, and need to go to the next leaner needle. This is where the confusion comes in.

KHI Part #
16009-1823 R1171L/2AFLM
16009-1824 R1172L/2AFLN
16009-1825 R1173L/2AFLP (stock)
16009-1826 R1174L/2AFLQ
16009-1827 R1175L/2AFLR

Okay which is leaner and which is richer? Higher No# or lower? I've tried to de-code the 2AFL_(M thru R)(is this the diameter?)but no luck.

Better yet what is the Keihin No# for a R1173L?
R=Keihin #N427-48??? 11=1 deg 15 min taper
73=(73*.01)+2.005= 2.735mm straight sect. dia.
L= L1 measurement (which I can't find by the way)

Maybe I'll go out and measure the stock needle and go backwards and try and solve this one. If I am headed in the wrong direction, please let me know. Don't think I need to mess with the main jet yet(I've been wrong before, and I admit it).

Also, most of the riding is 1st to 4th gear woods, and maybe 1/4 to 3/4 throttle at the most. Any help is appreciated.
Signed,
Dazed and Crazy

 

[dirt bike dave]

The 1174 needle will be leaner than the 1173. With needles, the higher the # means a fatter needle, which is leaner. I think the list you gave is in order from richest to leanest.

 

[canyncarvr]

re: can't find L1

Needles such as R1173L are kawi proprietary...so you won't necessarily find a keihin direct cross. You have to do some interpolation off the available numbers on either side to get an approximation.

As dbd sez...the larger number you're looking at (ie: diameter), the leaner the needle.

Basically, if your measured # represents a HOLE (a jet), the larger the richer.

If it represents a THING (like needle diameter), the larger the leaner.

You might consider JDs tuning guide software. It's available from thumpertalk.com. You can graph needle profiles and AF profiles for up to five different needles.

 

[KDXFreestyle]

Speeking of jetting, do pipes tell you what jet tp use when you buy a new pipe?

 

[RJ-KDX]

Thanks all.

CC, It's weird how those things just happen.

 

[RJ-KDX]

Alright I've measured the needle:
The needle has a step in it so it has 2 dia's;
Largest: 2.883mm
Smallest: 2.692mm
L1 section: 28.956mm

All of which makes no sense. The L1 is too small; the big diameter is off the chart; and the smallest is close to a K(2.695)(that's only a .0001" diff.)and that's it.

If any of you 220 riders have bought any other needles other than a KHI direct replacement or up/down a size, I'd like to hear from you.
Thanks in advance.

 

[fatty_k]

My 220 is a bit rich right around the mid, with the same needle you have. I have tried moving the clip up/down, but the little burbble is still there, so I figure go to a leaner needle. I also read the article on JustKDX, and cannot understand any of it, so I am just gonna wing it and buy the next leaner needle, and not worry about all the L1 and stuff. So I am going with the R1174 needle I guess.

 

[jaguar]

see http://www.mxsouth.com/keihin/keijetneedle.htm
From R1173L the "R" is the Keihin part #, the "11" is the taper in degrees which is 1degree 15minutes, the "73" is the diameter at the fattest part which translates to option P 2.745mm, and "L" is the L1 length (top needle clip notch down to where the needle has a width of 2.515)) on the upper diagram of the needle which the chart doesn't list but it could be a length between the listed "K" (38.6mm) and "N"(39.95mm).
Theres no direct cross to your stock needle. the Kawasaki R1174L would be the next leaner. The Keihin # of the next two leaner ones are N427-48BGP and N427-48BHP which give the next two longer L1 lengths which is like lowering the needle to make it run leaner.
But I think you should just leave the needle alone and lube the engine normally instead of going 50:1 which is just too much. I run 35:1 semi-synthetic Motul oil and never foul a plug. When you put in less oil then your engine is actually sucking in more gas which means you just jetted it richer. Go to 35:1. You'll like it.

 

[RJ-KDX]

Jaguar: I think you missed my earlier post. After measuring the needle, none of the dimensions even come close.

The D dimension is 86.5, a Z is 83, and that would be smaller, and if it's available. The L1 is shorter than anything listed at 28.956 and a C is 36.35, so maybe close to an A.

The thing that is really interesting is the needle is stamped with R1173L/2AFLP. When you mic the D's, it no where close to a 73(2.735) and I got 2.870(86.5). I donno.

If MXSouth has these for $5, I think I'll pick up a few and see what they measure. The real answer is to order a KHI R1174L and try that one.

As far as the oil is goes, it's what Amsoil recommends. ;)

Thanks again. :thumb:

 

[jaguar]

You measured L1 from top of taper to top needle clip notch?
Amsoil is correct in that you can have just enough protection at 50:1 but they won't tell you that it will throw your jetting off.

 

[RJ-KDX]

Jaguar: I measured from under the top notch to the start of the taper. The oil is not the issue, you always re-jet if you change ratios. Thanks again.

 

[acutemp]

RJ-KDX,
The reason that you are coming up with different numbers on your L-1 is that the L-1 is not measured to the start of the taper but at a point in the middle of the taper that measure's 2.515. Take your caliper's and set them to 2.515 and drop the needle through and where it stops you have your L-1. :) --Dan

 

[RJ-KDX]

acutemp: Thanks a million. I overlooked an important spec all in trying to find the right needle. I just measured it and found it to be 39.01mm.

Closer to an "E" at 38.15, a diff of .086mm(.0339"). I'm going to order a BEP and CEP tomorrow from MX South. Think I'll try a different taper while I'm at it.

Thanks,
Rick :thumb: :yeehaw:

 

[canyncarvr]

Oh oh. Now that you know the 'magic number' (2.515) we'll have to kill you! ;)

You can run yourself silly on needles. I'd suggest using some of the gazillion hours already invested by others, like fishhead and dan.

Check out the archives and JD's input on the kdx on the RB carb thread. A 2.735 diameter I don't think is where you wanna go.

Keep in mind what the magic number entails. The steeper the º, the later the taper starts on a given L1.

That is (imo) the single most important thing to understand about needles...L1 and how the magic number works with different tapers. If it isn't abundantly clear, please ask.

Don't feed the trolls

 

[RJ-KDX]

Thanks CC, I think I know what you're talking about. A different taper is going to change the length of L1. As far as where the 2.515 is concerned. I've sorta waded through the archives, and found a little bit of info.

A 2.735 diameter I don't think is where you wanna go.

Ok then, here is a question for you: Stock needle R1173L right, how come it doesen't measure 2.735mm? It has two diameters on it, neither of which are 2.735. One is 2.6924(.106"), and the other is 2.870(.113"). Am I missing something here?

FWIW, I ordered a KHI R1174L needle, and a BEP,BGN,BEP, and BGP. The latter 4 are to play with. I'm going to replace the 1174 first.

Do you have any suggestions as to which clip I should start on first? :thumb:

Nothing in life is ever easy, if it was it wouldn't be fun.

Also, you didn't catch me feeding the trolls, unless you have pictures.


:yeehaw: :aj: :yeehaw:

 

[acutemp]

RJ-KDX,
The L-1 on different taper needles, say BEN vs CEN will stay the same. What changes is where the taper begins, the BEN's taper will start before the CEN as it has less slope to it. To complicate the matter even more the smaller the straight section is, the further down the needle the taper will begin. The needles are made as BE_, CE_ blanks with the straight section cut in last.

I would give the BGN a try . Start on clip 4 and you might try dropping down your pilot 1 size. If it runs strong right off the bottom but stumbles a bit if you wick the throttle on fast try clip #5.

Don't forget to try all different settings on your air screw .
Good luck.--Dan

 

[RJ-KDX]

Thanks Dan, When you say clip 4, do you mean 4th clip from the top? Also I have already dropped my pilot down one to a 40. Are you saying go down to a 38?
Thanks for the help. :thumb:

 

[canyncarvr]

If email notification worked better, I'd have seen this last week.

Anyway.......

From JD in an earlier jetting thread on this forum:

"As the straight diameter is richened the feeling of needing a richer clip position goes away. "

And.......

"For smaller bikes and MX type power I usually suggest a smaller needle straight diameter such as 2.695 or 2.685- CGK or CGJ. This may be important when using a #7 slide. The clip position range may be limited so the CEK or CEJ may be better, it is hard to tell until someone rides and tests.

These may seem like a stab in the dark and way off from where you are at but they are the standard needles. It is the stock jetting that is odd!

I will go out on a limb and speculate that Kawasaki thought this would be a sweet play bike and need very clean jetting. So they put a lean straight diameter (2.725, or 2.735) , a lean taper (1.25 degrees) , and a lean clip position (L1=39.95) and then came up with 1172N or 1173N. The higher taper start is throwing you guys off track by being lean then rich then lean in an extreme and (to date) unexplained way."

The reference to a #7 slide isn't meant to confuse the issue. The point is how a smaller straight diameter acts and where kawi's oem jetting fits in.


Needle clip positions are numbered from the top..the blunt end.

38 is indeed the next pilot size 'down' from a 40.

The personality of a 2-stroke can be changed from manic to depressive within a quite small range of jetting choices.

The FUN is figuring out what that range is for your bike and riding style.

The attachment should answer your measurement question. You probably have this graph on your 'puter somewhere if you've done much looking into needles and such.

...and don't forget the AS!!;)

 

[DVO]

If memory serves me, I read somewhere around here that if the leanest on the needles isn't lean enough, you need a smaller jet. Last winter I changed to a richer jet and rode with 40:1 to make it richer for winter riding. When the summer came I went back to my old jetting but started fouling plugs until I went back to 32:1-problem solved. You're too rich because of your oil-a thinner mixture flows more easily through the jets, resulting in a richer mixture. As Jaguar said, Amsoil will give you protection up to 50:1 but your bike is presently tuned to run at 32:1

 

[canyncarvr]

That suits for the pilot circuit, along the lines of '..leanest on the AS isn't lean enough..then you need a smaller pilot jet,' but not needles.

Needle profile, which includes everthing from straight diameter to slope º to L1, slope start, clip position and everything else concerning needles works in different throttle positions than the main jet. A too far off main jet can effect throttle response and how the bike runs IN the needle areas, but that's why you select a main first when you're jetting your bike.

Certainly fuel/oil ratio effects air/fuel ratio (richer/leaner). Fuel/oil ratio is generally determined by engine size and application, NOT by air/fuel requirements.

 

[Braahp]

Try a "7" plug or a BR8EG. Little hotter might just be the ticket. Be careful with the 7 though it might be too lean. I know you rave about the 100 octane but your KDX just don't have the compression to require higher oct. It can't possibly burn as well as regular 93. What kind of 100 octane is it? If its av 100 it definately won't run as well either. Try simple things first like the plugs. Might just be the ticket.

 

[RJ-KDX]

CC; Thanks again for the replies.

The FUN is figuring out what that range is for your bike and riding style.

Didn't you mean the FRUSTRATION?

Braahp; Thanks also. I was talking with a friend and we hit on plug heat ranges today. As far as the gas is concerned, you must have read my post on the FRP site. It's not that my bike needs it as much as I do. I know most here poo poo on it, but I can feel a difference.

DVO; I'm not sure why everyone gets so upset when people run at ratios above 32:1. This is my whole point to get my jetting SPOT ON. :thumb:

Also to clear a few things up I WAS going to go to 50:1 and sort out the jetting(Amsoil rec.). This has not happened. Went riding on Sat., changed needle to a BEP, 3rd clip, new BR8ES, and still @ 40:1. Ran out and did a plug chop and the plug was awfully white. Not wanting to waste a good riding day, I put the R1173 back in, and off we went. Throttle was a little boggy, but we had a good time.

Still open to suggestions. BTW, whats the major difference on a EG plug as opposed to an ES? Thanks, :eek:

 

[jaguar]

The only difference between the 1173L and BEP is that the BEP has an L1 almost 1mm shorter which means that for the same clip position it is richer.
You said "FWIW, I ordered a KHI R1174L needle, and a BEP,BGN, and BGP."
BEP: 1mm higher (richer for same clip position), same dia, same taper
BGN: 1mm lower (leaner for same clip position) slightly different diameter but not enough to matter
BGP: 1mm lower, same dia, same taper

How does it run off-idle and WFO if your 1173L is clipped in the top notch?

 

[RJ-KDX]

From R1173L the "R" is the Keihin part #, the "11" is the taper in degrees which is 1degree 15minutes, the "73" is the diameter at the fattest part which translates to option P 2.745mm,

Jaguar; How come an 1173 doesen't measure 2.745?

and "L" is the L1 length (top of taper to top needle clip notch) on the upper diagram of the needle which the chart doesn't list but it could be a length between the listed "K" (38.6mm) and "N"(39.95mm).

A length between K and N? Come on now....

The only difference between the 1173L and BEP is that the BEP has an L1 almost 1mm shorter which means that for the same clip position it is richer.

I don't think so. :scream:

 

[acutemp]

RJ-KDX,
Jaguar is correct, an r1173L on clip #3 is equal to your BEP on clip#2. The BEP on clip#3 would be slightly richer at full throttle than your 1173#3 would.

Your 1173 needle should have a straight section diameter of 2.735mm. The difference the 1173K and the 1173L is that the 1173K is half a clip richer.

Dialing in your jetting does get easier and is more of a quest than anything, be sure and keep a log of your testing as it will come in handy later.

Good luck.--Dan