450F vs 250F main jet comparison

Hey guys, this is my first post so go easy on me. I am new to the 450f crowd moving up from a 2006 Yz 250f. When during research on jetting I noticed that the 450f runs a smaller main jet than the 250f. I understand the the 450 has a 2 mm larger carb, but isn't main jet sizing nomenclature the same for any fcr carb. Thanks in advance.

Yes, all the jetting sizes, etc., cross the entire FCR platform. The 450 is a much bigger engine with a slightly bigger carb, and so has a significantly stronger vacuum signal drawing fuel through any of the jets. The stronger signal allows a smaller jet to be used to deliver the necessary fuel.

Thanks man!

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