Another Jetting thread

[Pack]

Alright, so I pretty well got it down pat on how to do it, except the whole "needle with clip on 4th position" or something. I know nothing about this.

And is the aftermarket fuel screw worth it?

I'll post more questions about this when they come. Sorry for another jetting thread.

[yfzrider690]

The needle is in the carb and needs to be adjusted when every you change anything. It controls 1/4 throttle to 3/4 throttle. You count down the notches from the top. So 4th position would be 4 down from the top. And yes the aftermarket screw is worth it. You have to take the bowl off to get to the stock one. When you get a aftermarket one you punch out the little plug and put the new one in and can adjust it from the bottom of the carb.

[Pack]

Do you happen to have a link/video/photo of where that needle is?

Also, what's the best position to put that?

Oh, and how will I know if I am running too rich? I know if it's too lean, it backfires often, but what happens if it's running to rich?

[yfzrider690]

Here is another forum that I go to a lot. This link has pictures and everything on how to jet and adjust the needle. If you are to rich you will know it. It will stumble and fall on it's face. I have the ncvq needle and would suggest getting it. Most people that have a yfz run that needle, it is out of the yz dirtbike. I have mine on the 4th clip down from the top. Here is the link.
http://yfz450.theatvchannel.com/invision/index.php?showtopic=53474

[Pack]

Where can I get a nvcq needle?

[yfzrider690]

You should be able to get them at the dealer. They are about 14 bucks.

[Pack]

Any specific year I need? My YFZ is an '07

[yfzrider690]

No, just tell them you want the ncvq needle. If they can't find it tell them it's the needle out of the yz dirtbike. I think it's a '04. They should be able to find it just by you telling them it's the yz needle.

[Pack]

Thank you, man. Also, where's the leak jet? I need to change it, as well.

[yfzrider690]

The leak jet is in the bottom of the bowl. Most people change it to a 35. I still have the stock one in mine as my quad doesn't seem to have the bog that everyone has.

[Pack]

You're a lifesaver. I'm getting an air filter Monday, with some vents in my airbox, and I already have an aftermarket slip-on exhaust. My carburetor isn't jetted right now, but as far as I read, I should go with around a 170 Main, 45 Pilot, and 2 1/2 turns out with the fuel screw.

As far as I've read, around the 3rd or 4th position on the needle (not sure which one, or even if there's a big difference with the two).

Does all that seem right?

[yfzrider690]

Ya that sounds pretty good. Maybe a 48 pilot. If you have to go more than 2 1/2 turns on your a/f screw than you need to go up a size on your pilot.

[Pack]

I think I'm set and ready to go. Thanks again.

[yfzrider690]

No problem. Keep us informed on how it works out for you.

[Pack]

Definitely.

Where can I buy a size 35 Leak Jet?