Needle jet sizes

[gearhead13]

Calling carb gurus!
I have two sets of needle jets, one set is brand new and is marked y-5, the other is a used set (35k km) marked y-1
From looking at this page:

http://www.sudco.com/Catalog37Digital/index.html#/212/zoomed

Every step up of the number makes the diameter .005mm larger, so the difference between y-1 and y-5 should be .02mm, seems like a tiny difference, but because the used set is worn a little, how much of a difference would there really be. Does .02mm REALLY make that much difference, maybe compensated by one notch in the needle clip position

[Guest]

It appears you can still get the factory parts. I couldn't find a factory chart, with the needle designation. A clip position makes a lot of difference, I would stay with stock sizes or look for a jet kit for specific changes. Dynojet makes a stage 1/3 kit for your bike with jets and needles.