dyno jet vs mikuni jets sizes ?

Why when i purchased a 165 mikuni jet it was alot larger in the hole size than dyno jet 165? I had my old needle in my dj box and decided to stick it in the dj 165 and than mikuni 165 and my god big difference.I also did the 160 on both aswell,and again they are different.Could this be just a manufacture error or are the two companies not play well with each other?The reason i ask is when we get jetting help on this awsome forum, are we to buy mikuni jets or dj jets?I heard Eddie saying there is no difference,but i could not believe my eyes.

My bike is 2007 drz400s.



k&n filter.

160 main jet(mikuni).

27.5 pilot jet 3 turns(kteck).

Hotcams IN and OUT.

3.5x3.5 hole on top(i know).

15/48 gears.

This bike is quick,power lifts up in 3rd and in the right conditions also in 4th.

I love everything about this site.

I called dyno jet with that very question this week. Some are rated by flow and others by dia. You have to use dj needle with a dj jet. Or kiehn with kiehn. I am currently running a 175 kiehn and wanted to know what to start with for dj. The largest main jet in the dj kit is a 165.

there is more to how much fuel a jet flows than the hole.

when you measure actual a/f ratio they are nearly identical.

I am confused Eddie,The 2 jets i have(165 dj &mik),The mikuni I would guess flows 20 percent more fuel than 165 dj,from what i measured here.So how can that be? To me it sounds like in jetting the numbers dont matter because there is no consistency with it. For me and what i have seen these jets i have, cant be so,,,,unless these jets are faulty.Can i send the two to you eddie and you confirm me findings?Where i live no one has o2/fuel meters and or dynos,so fine tuning is very hard for me.

is it a genuine mikuni jet? if not,throw it away. it also wouldnt be the first time there was a mis marked dynojet main jet.

the numbers most definatley matter.

you need to under stand that just comparing the size of the hole doesnt mean everything.the taper in and out,length of the bore,etc all inlfuence the jets ability to flow.

you cant guess the flow on a jet.

Thank you Eddie,I wish you were not so far,my bike is dam near there, but i need you to give it the touch of perfection.One of these days i will buy the fcr mx,Do you have a coupon,lmao

O and yes it is genuine,but to make sure i will go to another dealer and order it again to see,that is the jet i need as for your recomendation before.Thank you again so much Eddie wish i new as much as you forgot in one day,And then maybe i could get it.

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