Help with different Keihin jets!

I bought a '09 yz450f, that had a JD kit in it. It was jetted for a different altitude, so I need to lean it out a bit. The Jet on the left is a 170 from the JD kit, and the 2 others are a 168 and a 165 from the local dealer. Notice the "collar" inside is quite a bit deeper on the jets from the dealer than the JD one. Also, the JD one has a little sort of half star design and the others say "AB" on them. Can anyone help me out with the difference between the two? And, will going from a 170 "shallow collar" to a 165 with the deeper one have the same effect as two that are the same?

Any help would be greatly appreciated!


The star is Keihins logo

JD only uses Keihin jets.

All actual Keihin jets flow the same, so a 170 is a 170 (assuming both are undamaged and spotless). There are aftermarket companies selling knockoffs that have been reported to not match exactly. I suspect the dealer jets are not actual Keihins but knockoffs.

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