Jet Needle Question

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m0rie
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Jet Needle Question

Post by m0rie »

Has anybody tried a NOZF or similar triple taper needle in their RB'd KDX carb? Comparing a NOZF/2 to a CEK/4 and a DEK/4 in JD's sheet shows a profile that should respond like a CEK for the first 1/2 throttle range and then end up more like a DEK after that. Any thoughts?
1989 KDX 200
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KDXer
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Post by KDXer »

BRADLEY !!!!! HELP !!! :lol:

Now that I have my RB carb and a few different needles (CEL,CEK,DEK) I'm gonna sit down with a needle tutorial from Brad and 'TRY' to soak it all in. Cheers....
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canyncarvr
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Post by canyncarvr »

Do a sit down with the XL spreadsheet jetting guide from JD!

m0rie: FWIW...The NOZF/2 looks to be almost identical (saying I don't see the difference) to the CEK/4 in both needle profile and relative jetting.

What am I missing?

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Argued before...but isn't an NOZF a double taper? Meaning, two different taper starts, two different angles? Not that it matters..semantics is all.

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m0rie
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Post by m0rie »

Thats wierd - My graph looks completely different.

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NOZF has three tapers:
0.500
1.567
3.000

Now I know the 3.000 degree taper isn't even close to a D taper (1.750) but do you think it might behave like the D taper needles do later in the throttle range and rev out in comparison to a C taper?
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canyncarvr
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Post by canyncarvr »

The multiple taper doesn't even show up at all in my JD rendition. That surely points to a problem with my version somehow.

Curious..input on my version works only with an 'NO-Z-F' entry. The 'example' page shows input should be 'N-O-ZF'..but that gives me an 'incorrect entry' complaint.

What is the format of your entry?

As far as telling what will happen realtime based on the graph..I don't know.

Seems the considerably richer bottom (1-8/1-4) of the NOZH wouldn't be near as nice as what I've come to appreciate with the longer/leaner straight of the 'D'. That would come from the .5 at the start..and how EARLY it would have to start due to the slow angle. From the chart, the NOZH seems to be quite at odds with why I use a 'D' in the first place.

But...you can straighten all that out after you ride with one!! :roll:

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Post by IdahoCharley »

Little off topic but FWIW - I did try the JD Blue and Red needles in a stock 35PWK carburator with a cut stock slide (~7-7.2) on a KDX 200. I felt the Cxx and Dxx series needles were better. The JD needles are dual taper needles.

Also tried a NOZI (triple taper) and it just was too rich near the bottom end even with the modified slide and fuel curve too high on the top end. When you limit the top end with main jet size that you lose the mid section.

Also tried a 85C maybe it was a 85B (dual taper needle) and dismissed it because the JD needle worked better.
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m0rie
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Post by m0rie »

IC - Thanks for the input. What you experienced with the NOZI is pretty much what everybody seems the end up with. I just hadn't run across somebody that had tried it in a KDX yet. I'd still like to find a needle that had a C taper for the first half and a D taper for the second. Seems like it would be the best of both worlds during the summer when there is enough traction to be able to make use of the strong bottom end hit the C taper needles have and transition into a nice pull and over rev from D taper.
1989 KDX 200
2007 TTR-50E
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