Jetting Experts – a Needle Question

Jetting Experts – a Needle Question

Hi all. My 2006 is “uncorked” and has plenty of power, enough for me. On another thread I was trying to fix a sensitive/snatchy throttle at very low openings, now cured by a larger pilot jet. This was very evident with a cold engine where it would take ages to warm-up and get past the lean boggy feel once the choke in.

Anyway, to the point. The WR has a fat, lean, needle on the straight portion – #GDDUS - the “S” designates the straight part, whereas, as an example, on my DRZ I have a thinner needle with a number ending with N.

In case you haven’t tried, the straight part affects very small throttle, enough to need the fuel screw adjusting when swapping needles, interesting.

I tried a needle with identical taper to the stock WR but ending in “Q” – two sizes less -the straight portion is 2/100th mm thinner.

Not really much different, but what I want to know is what straight portion is the “correct” diameter for an uncorked WR, as this effects low throttle openings, my area of interest. The rest of the needle I’m happy enough with stock.

Thanks for any ideas…


There is no one correct needle straight diameter. There is the correct one for you, where and how you ride.

Your knowldege is correct. The change in diameters are very small increments. A significant change is often needed to be identified by the 'Butt-O-Meter. Try a needle endin in 'N'.

When you test needles, be sure to have the correct pilot and fuel screw in for proper idle as with it oversized, you will be getting incorrect needle evaluation.

Thanks William1 - I have posted a reply on my other thread:

But would still appreciate it if anyone could chip in with some needle suggestions. It seems many are using the JD needle, don't suppose anyone would care to measure the straight portion diameter for me .... ? .......


Personally, I think AP settings are more important for the low rpm throttle response....

Personally, I think AP settings are more important for the low rpm throttle response....

OK, but my particular issue is at very light throttle, before the AP kicks in properly. Plus.... playing around with various jets affects things significantly, without touching the AP, plus (!) you can feel how the engine is at a steady throttle ie no AP.


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