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07 YZ 450...just can't get it right!

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I just can't get the jetting dialed in on my 07 YZ450! I did the circuit adj...bumped up the pilot jet to a 48 from a 45 and bumped the main to a 170 from a 160. I'm riding in the high desert with alt. ranging from about 1500ft to 3000ft. The 48/170 set up was recommended by a bunch of people, but it sure isn't working for me. The off idle response is terrible, and in the slower stuff it just wants to crap out. Hopefully someone can help!!

Justin

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its all about the fuel screw set up and check your idle, stock jetting should be fine with screw adjustment.

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I had the best luck with stock settings, well intentioned people at the track helped me adjust fuel screw but stock is where I get the best performance. a friend changed the jets on his and it did run a little better in the cold of winter according to him but now that its warming up he wishes he never messed with it. good luck.

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I just can't get the jetting dialed in on my 07 YZ450! I did the circuit adj...bumped up the pilot jet to a 48 from a 45 and bumped the main to a 170 from a 160. I'm riding in the high desert with alt. ranging from about 1500ft to 3000ft. The 48/170 set up was recommended by a bunch of people, but it sure isn't working for me. The off idle response is terrible, and in the slower stuff it just wants to crap out. Hopefully someone can help!!

Justin

I ride in the same conditions, I run a 45/170 right now, but if your going to make a change I would go 45/165 or 168. Then adjust your fuel screw as needed, I say this because I have no idea were mine is set at because it always changes. Somewere between 1.5 - 2 turnes.

Right now your bike should not be running all that bad, I think you should check your fuel screw, it may have backed out. Also make sure your air filter is clean and oiled, if it's dirty that will screw with your bikes performance.:applause:

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go back to the stock jetting and start from there....and test the bike and try to sense where u feel the bike is too rich or lean

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What needle does it have (answer is not "stock" it is the letters stamped on the needle)

Not sure? But I tried 165/45 this weekend and it is liking it much better! Not sure if its perfect yet, but much better then it was.:applause:

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mine stumbles off the bottom a little bit. i have moved the clip and messed with the air screw and it is still there. on the 06yz you had to get a fmf jet kit the needle is different the look is the same but there are moreclip positions and they are cut in a different spot so if it calls for the third clip position down on the stock one the new needle will be in a different spot in the third clip position on the new one may be try that. the kit gives you everything and tells youwhat jets to put were i did it for a friend and itworked his wouldnt even idle it would shut off and shoot flams hope this help joe 913

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Ya I am in Norcali near Hangtown so pretty much sea level.. I have full WB pro 2 system and ive had a hek of a time trying to get it to run right. Never had so many jetting issues .. I have now a 168/48 and 45 leak and I just dropped the clip from the 4th to the 5th position.This was told to me from Al Posey a well known engine builder here in Norcal. My problem was the bike would stall alot if I came into a corner and pulled the clutch in it would die then try to bump it and never would work.

Im going riding in a little bit and see if the clip drop made any difference, if not im not wasting another minute on this thing im taking it getting it dyno tested and jetted perfect (if there is a such thing)

oh ya I have messed with the fuel screw so much its worn out and loose (pos)

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