Main Jet Part numbers

Does anyone know for sure what the part numbers are for the #178 and #180 main jets for the XR650R? I'm a little confused by similar numbers that I've been finding.

I just got back from the dealer and the parts guy said Honda does not even make jets as big as the 55/158 set-up I wanted. He's going to order them from somewhere else. It didn't sound right to me, but that's what I was told.

I see that they have Keihin main jets in those sizes at the TT store. Does anyone know if those work with the stock carb?

Yes. Any Keihin "hex" main jet will work--they're all the same, not carb/bike specific. Honda doesn't actually make the jets--Keihin does. Keihin main jets can be sourced from anywhere (inlcuding Honda). There's a vareity of Honda part numbers that will get you Keihin 357 Series (aka "Hex") main jets. 99101-357-xxx0 is one of them. Just replace the "xxx" with the size you're after.

If it looks like this and has a stylized "K" in front of the number, it's a genuine Keihin main jet.



Thanks HawkGT. I'll just order the Keihin main jets and forget about going through Honda then. I'll go to the dealer for the 68s and 70s pilot jets.

I just did a little research and if you go to you will find everything you need. They charge about 6 buck per jet.

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