I think you need the dimensions to match it? For example: it’s
8.5mm in length with a 3.5mm Round Head.

This may shed some light on things…..
http://www.thumpertalk.com/forum/sho...d.php?t=239791

Then maybe your looking for this…I am not sure though.

Keihin N424-52 OEM FCR-MX Leak Jet
8.5mm in length with a 3.5mm Round Head

then you could find that here:
http://www.pjmotorsports.com/keihin-...ot/slow%20jets