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Discussion Starter · #1 ·
anyone got a chart that tells you what size jet corresponds to what size number drill?

i've been bussily rejetting, but everytime i want a different size i have to order in from another country!!

I have spares from 155 to 170 & it would make it a lot easier if someone knew what number drill corresponded to say
180, 185 & 190 mains, so i can drill out the smaller ones that i no longer need.

Jets are long hex type to suit 41mm Kehin carbs.
 

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I'm no help with the drill sizes, but I wanted tolet you know that you shouldn't have to be ordering jets from overseas.

Lots of bikes use Keihin carbs that share the mains w/ FCRs so you should be able to get the jets locally. KTM I know for sure, but when the KTM dealership doesn't have them I can get them from the Suzuki/Kawasaki dealership next door.

Carbuetor Parts Warehouse should have anything you need as well. (they also have a jet list that shows which other bikes/carbs share the main jets)
http://www.carbparts.com/

--Fillmore
 

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OK, sorry Chris... I just saw where you are from.

Maybe there isn't a Kawasaki dealership next to the KTM shop in Port Moresby, Papua New Guinea. ::)

(BTW, Maybe I'm wrong about this, but I always assumed jet sizes were in ten thousandths of an inch, i.e. a 170 jet has a diameter of .0170")

--Fillmore
 

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Discussion Starter · #4 ·
Fillmore,
thanks for the tip.

You will probably find this hard to believe, but where i live, a country called Papua New Guinea, there is no such thing as a motorcycle shop, not even one!!

This is why i need to Air freight everything i need, pain in the a$$, i know, even air freighted the bike in when i bought it.

thanks for the link, i'll check it out.
 

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Some jets are 'numbered' by the diameter of the hole, some are 'numbered' by the flowrate, and doubtlessly others are 'numbered' by some other arcane method.

I know Mikuni had both kinds of numbering systems on different styles of jets, small hex and large round as I recall, don't know what Keihin's system is.

Chris in New Guinea, If I were in your shoes, I'd check how much the diameter increases from the 165 to the 170, for example, and then use that to approximate 175's, 180's and so on. You can get a pretty good idea of the size of the hole by what number drill is the best fit.

Beware that jets are high precision pieces, so your version of a 180 will likely flow different from a factory 180. It's not a big thing really, because if your bike runs good with_your_180's, that's all that matters.

When you make 2 180's, they may each flow slightly different, so if you find that the horizontal cylinder looks richer than the vertical, you could swap 'em to help cool that hotter vertical.
 
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