[boxin]

Because if 15 is really what I need (.38 mm), then 37.5 would be something like 0.9 mm, and the seller also offers 65, equivalent to 1.7 mm, too much for a jet pilot! With these sizes, seem Main jets, That's what I do not understand.

[arsenic]

You have officially made zero sense. For starters stop spouting off numbers like .38mm. If you have 12.5 and need 1 size up, BUY 15!

[boxin]

Let's see if I can explain better, "zero sense"... I will try to improve my English, I do not speak it well.
If you look at this list of parts (Katana 600 2001)
- .JET, PILOT (#12.5)
09492-12008
.
.
.
- .JET, MAIN (112.5)
09491-22014

You'll notice the absence of the symbol # in the main jet. Well, 112.5=1.125 mm in diameter. The #12.5, is 12.5x2.54 = 31.75, or 0.3175 mm in diameter. 0.32 mm is a normal value for a jet pilot! And the difference with 112 of the main jet is also normal. That's why I do not understand what nomenclature use the seller.

[arsenic]

No it doesn't, Mikuni doesn't number them that way. That's Dynojets numbering system. A Mikuni 112.5 means that it meter 112.5 cc of fuel per minute.

[boxin]

Okay, I'll follow your advice and buy the number 15. But I still do not understand the difference of "#" and "not #" between pilot and main jet (see mrcycles.com).
And the equivalence between #15 = 0.38 mm and 112 = 1.12 mm, I measured it myself! With the help of a friend and this tool:

I suppose it was coincidence. Or luck!
But I will follow your advice friend, thanks!

[Kreylyn]

Okay, I'll follow your advice and buy the number 15. But I still do not understand the difference of "#" and "not #" between pilot and main jet (see mrcycles.com).
And the equivalence between #15 = 0.38 mm and 112 = 1.12 mm, I measured it myself! With the help of a friend and this tool:

I suppose it was coincidence. Or luck!
But I will follow your advice friend, thanks!

Coincidence...

The size for OEM jets is by cc flow, not the hole size.

Krey

[steves]

http://katriders.com/wiki/index.php5?title=Jet_sizes