That needle is a Honda needle and you can read all about Buzzards experimentation with the Honda set up here:
http://www.husaberg.org/index.php?name= ... pic&t=5326
I'm running basically the same set up in my 04 550, except a bit leaner due to the stronger intake impulse of the 550. I will say that the difference in the low to mid power is impressive, as well as the response.
Here's the Kehin sites list of needles:
http://www.keihin-us.com/needle.htm
If you go to my gallery I have listed the temp/altitude conversion tables, and the needle sheet for the 06 CRF 450R. You will then be able to use the kehin site and the honda sheet to compare the differences in the needles. Note especially the L1 length difference between the DVR, and the CYR. The CYR needle is 30 seconds of a degree or 1/2 a degree, while the DVR is 45" seconds of a degree or 3/4 of a degree in taper. However, the L1 distance is 58.96mm's for the CYR, and 82.75mm's for the DVR.
Read Buzzards post, he pretty much covers the bases on these Honda needles.
I'm currently running the following:
NCVR needle @ pos #3
160 main jet
40 pilot jet
HDJ emulsion tube
Honda Diaphragm
Stock air jets.
I'm running at around 4500' msl, and this time of year its around 30F in the morning and 55F in the afternoon.
