JD needle specs

A reference for the PWK carbs...
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JD needle specs

Post by smelonas »

Noticed that there was some info/questions floating around about the JD needles and their diameters. I do not have a lot of information currently as I just got the kit and havent even rode the bike yet, but that does not stop me from taking measurements from the stock 1174 and the RED needle. Set up my bike so long ago that the stock needle was still considered 'good', holy ****, what else am I missing out on?

Lets get to it.

'D'iameter on the needle
JD Blue and Red: 2.88mm
1174: 2.78mm
These measurements do not line up with the chart and the alleged diameters from Keihin themselves, BUT, a takeaway would be the difference in diameters. So we know the JD needles are about 0.1mm bigger in the diameter versus the 1174.

Tip of needle diameter
JD Blue: 1.97mm
1174: 2.02mm

Length to bottom clip position from tip
JD Blue: 60.35mm
1174: 60.36mm

Mid length diameter (between bottom clip postion and tip)
JD Blue: 2.68mm
1174: 2.66mm

So there is a little information on the JD needles. We know that they are leaner till about the halfway mark and then richen up towards the end of the throttle pull. Which, its almost like they dyno tested these bikes and found that they were too rich on the bottom and lean on the top from the factory. Incredible. Ive used the JD needles in the past on 2 and 4 strokes, always worth the money. Its like shortcut dyno tuning with a needle.

We all know the #7 slide and a proper main/pilot combo will finish off the rest of the tuning, but so far as I can tell, I should be in for a surprise when I get to rid here in a month or so! Especially with the new #7 slide! Lot to look forward to.
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Re: JD needle specs

Post by kdxdazz »

in 1 year nobody has corrected this. jd needle cannot be 2.88mm it wouldn't even fit in the emulsion tube if it was
1174 needle is 2.74mm not 2.78mm, the clue is in the name lol
not only that you said the jd red and blue needle are the same diameter yet the straight diameter is the only difference,
974 views and nobody has said anything
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Re: JD needle specs

Post by SS109 »

Well, you could have corrected it a year ago! :mrgreen:

I couldn't correct it. I don't have the info myself as I have never purchased one.
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Re: JD needle specs

Post by Slick_Nick »

I never liked the JD needles. CEK or DEK for me depending on the power delivery I’m after.
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