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Discussion Starter · #1 · (Edited)
Mightydaj,

Here's the measurements of the needles you requested, and confirmation that the Dyno Jet needles are thinner (richer). With the adjustable clip on the DynoJet needles there would be a few ways to measure them. I elected to leave it on the 4th notch (from the top) as I was running them. The range of adjustment is three notches up (.120"), or two down (.080").

It appears that the root diameter is actually .002" thicker on the DynoJet needles, followed by a faster taper down to .058" @ 2.05" from the bottom of the clip. compared to .064 @ 2.05" on the stock NBZT.



Also, I measured stock and DynoJet springs just for giggles:

SPRINGS STOCK DYNOJET
OAL: 3.92" 3.36"
WIRE: .0275" .025"
TURNS/INCH 2.75 5.25

The DynoJet springs are signifigantly softer!
 

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Discussion Starter · #2 ·
I should add...the DynoJet needles are part number DNO308 from the 865 Bonneville kit. The 790 kit comes with different needles, DNO369.
 

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This is very useful information, thanks for taking the time to do this work and for posting the specs. I for one will be making good use of it and appreciate your efforts.:thumbsup:
 

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Just thought of something. Do you (or anyone else) know if dynojet springs must be used with dynojet needles, or can I use the stock springs with dynojet needles?
 

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i have a question related to the dynojet needle. i installed the dynojet kit awhile back, and while it was worth it i don't really know the theory as to why the needle is better than the stock. could you please explain it to me?
 

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i have a question related to the dynojet needle. i installed the dynojet kit awhile back, and while it was worth it i don't really know the theory as to why the needle is better than the stock. could you please explain it to me?
With needles there are two variables, the needles profile and its height setting. The Dynojet needle has a different profile to the stock needle and is adjustable both up and down whereas the stock needle can only be lifted up by the use of shims.

The Dynojet needles thinner profile means you get a richer mixture at any given height than the thicker stock needle when using the same main jet size. The added adjustability of the Dynojet needle gives greater flexability which can help achieve a perfect A/F ratio in the throttle range that the needle is effective.
 

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Hi. Hopefully you are still out there after all this time. I have a 2001 Bonneville. I'm going through the carbs on a bike I bought last year. I have found there was some mods that had been done once upon a time. The bike had stock pipes when I got it, but seemed to run rich. I'm doing the BC ark, D&D megaphone exhaust, and DNA pods. The info I originally got from different sources took into account stock needles, but as I opened the carb I noticed the Dynojet style. Knowing this, I'm wondering if I'm better off buying stock needles or finding a way to make the others work. First time around at this and I want to do it right.
 

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Shestak, I would recommend you get the stock needles to begin with. My '03 790 runs a bit rich in the mid-range with the STOCK needles (NAGB). I would also recommend starting out with 155 main jets after your mods, and I would keep the 40 pilot jets (I would start at about 2.5 turns out on the pilot screw). You can see below what I run after tuning on the dyno.

NOTE: The jet numbers I mentioned and that are shown below are for Keihin brand jets. If you have Dynojet brand jets in the carbs or use Dynojet brand jets, the numbers will NOT be the same for the same fuel flow. I have seen a cross-reference chart on here many years ago, but I have never used Dynojet products.
 

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There were DJ needles in the bike when purchased and after much fiddling and farting around, I bought some Thrux needles and springs and basically eliminated all this nonsense. If one was interested in constantly tuning for atmospheric conditions or racing, then the flexibility of settings might be fine. But for street riding, I just didn't want the pia tinkering.
 
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