I got a HMF exhaust and now i needa jet my yfz i was wondering what is the best jet kit and what will have the right size jet and i need a 180 jet

 

I would not waste the money on a jet kit, and I am sure a lot of others would agree. Just run down to your local shop and buy the keihin main and pilot jets that you need. Probably 168-178, depending on what you have done. A 45 pilot should be perfect, unless you have the cam mod, then you'll need a 48pilot. The yz450f dirtbike needle is the needle to get, its the same as the aftermarket GYTR needle for your yfz450. If you do that needle, a 180 will be way to big. you would only run a 180, maybe, if you kept the stock needle in there, which I dont recomend.
But thats what I would do. I started with the dyno jet kit, and that kit is horrible, havnt heard of one person having any luck with it on a yfz. Then I was going to get the GYTR, and the problem with it is, if you plan on doing any extra mods, besides an exhaust and filter, you will run out of the range of jets in that kit. Plus, its like 50 or 55 dollars. The way I said to do it should only cost you like 25-30 max! Its what I did, and many others did, and I have mine dialed in perfect!
Also, go out and buy yourself a ziptie fuel/air screw. This will make it much simpler to tune your air/fuel mixture. They are available from Alba, and I am sure many other places.
...........Hope that helps

 

Sounds good thx

 

Yes dont buy the dyno jet kit. Thats what i got and it sucks. It didnt even come with the pilot jet.

 

huh but stock needles and jet's? really