what needle what do the numbers mean?

[StreetLimitz89]

okay, i have a R1469N needle currently in my Cr125R and i was told to use a R1468N, would a 1468 be richer of a needle or leaner?

 

[dirt bike dave]

Slightly richer.

The lower number needle is smaller in diameter, so it blocks less of the needle jet and lets more fuel past.

 

[RM_guy]

The numbers also identify the needle taper as well as the location of the notches realative to the start of the taper. Here's a chart for Keihin needles.
http://www.keihin-us.com/am/_media/pdf/fcr_jetneedles.pdf

 

[StreetLimitz89]

well, here ill show you a quick video i made of the bike the day AFTER we got the bigbore fully installed, the sound is off on the video, IDK why but you can still hear the noise its making getting into the top end, the main jet is a 172, the pilot is a 52 and the needle is a R1469N in the very FIRST clip, moving it further makes it worse, so we really dont mess with that for now.

http://www.youtube.com/watch?v=vdPse498aaw

Dont mind the laughing, a buddy of mine is almost 7 ft and he looked like a doof riding that bike