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Thermos O flask

jetting changes with yz cam?

8 posts in this topic

I've got the yz cam (au$211 delivered to sydney, thanks "jp parts") what jetting changes am i likely to need to do on an '03 450,yz muffler,jd kit,grey wire,i have a #40 leak jet to put in at the same time.So Go a bit richer on the main? 1 clip or a jet size? what have you done?

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I don't have the YZ cam in mine but since no one has answered you yet, the cam itself shouldn't change your jetting. When the exhaust cam comes into play, everything it needed to run has already been delivered. The YZ exhaust cam just holds the exhaust a little longer than the stock one. In turn ( I guess ) making a bigger boom going out and throwing the piston down harder afterward. If you were changing the intake cam you might see a need for more gas. The WR Performance Index thread has the jetting forum in it. That should take care of everything else.

If I'm wrong, I'd like to know whats right. Feel free to jump in.

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yea,sounds ok.I thought maybe as the yz cam would give more power to the topend,i would need a bit more fuel?

But i suppose i just bang-her in and see what happens.the jatting cant be that far out.

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i have a yz cam in my 07. now that its getting warmer in wisconsin i just leaned it out a bit main 165,pilot 45, needle NCVQ middle runs great. I dont understand why guys are useing 170s, and 50s I had mine at main 168, pilot 48, and rode at motoland in Indiana on sunday 75 deg and it was way to rich.

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My 05 runs better and makes a lot more usable power when its "rich" according to the jetting people are puting on the jetting thread.

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yea,sounds ok.I thought maybe as the yz cam would give more power to the topend,i would need a bit more fuel?

But i suppose i just bang-her in and see what happens.the jatting cant be that far out.

The jetting on my wife's quad even stays the same with a came change unless it changes the intake part dramatically. Its a Honda Unicam. You do get more top-end from the YZ cam. The way I've read about it, you get a little more everywhere.

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I dont understand why guys are useing 170s, and 50s I had mine at main 168, pilot 48, and rode at motoland in Indiana on sunday 75 deg and it was way to rich.

Ditto.......I have been wondering the same thing. I have my ACV deactivated on my carb and I have to run a 40 pilot jet and 165 main at 3000 feet 70 degrees F.

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If 14.7 air/fuel ratio is perfect,then rich is too much fuel and lean is too little?

Then the object of jetting changes is to get it as close to 14.7AF or perfect as possible.Sounds good in theory anyway...:bonk:

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