Jetting 101.

83620 Views 158 Replies 113 Participants Last post by qes, 14 d ago

Duane

Discussion Starter · Jul 7, 2006

17

How to jet the carb on the YFZ.

Step 1: Drain the carb of gas.

Step 2: Unplug the TPS and carb switches to spin the carb. Unplugging is optional. You may have enough room to rotate carb without removing the plugs.

Step 3: Loosen clamps that hold the carb. One on the intake side (not shown) and one on the leaving side of the carb.

Step 4: Spin carb to access the jets by removing the 17mm nut at the bottom of the carb bowl.

Step 5: Replace jets as required. In these pics I removed the bottom of the carb to get better pics. YOU DON'T NEED TO DO THIS!

Step 6: Getting to the needle and clip. Remove the plate on top of the carb.

Under the plate you'll find an allen head screw that needs to be removed to get to the needle and clip.

Remove allen head bolt to remove the needle and clip.

Reach inside the back of the carb to "lift" the needle out.

Needle and clip.

WARNING: DO NOT MOVE THE TPS SWITCH WHILE DOING THIS!

That's my basic "jetting for dummies" tutorial. Make sure everything is clean before doing any of this because dirt is your worst enemy. After you're done make sure everything is put back in place and all switches are plugged in.

EDIT: This is what you'll see on the 06-07 YFZ's when it comes to the fuel screw access. Thanks to Fever2ride for providing the pics.

Yamaha blocked off the access with a plug and you can either pop the plug out by screwing in a sheetmetal screw or take the bowl off and punch it out from the inside.

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1 - 20 of 159 Posts

chaos

· #2 · Jul 16, 2006

Is the TPS the thing the pen is on? (I think thats the idle) Or is the where the arrow is? Im confused!

Toadz450

· #3 · Jul 16, 2006

Originally posted by chaos@Jul 15 2006, 10:09 PM
Is the TPS the thing the pen is on? (I think thats the idle) Or is the where the arrow is? Im confused!

[snapback]454970[/snapback]

The TPS is what the arrow is pointing to. The pen is pointing towards the idle screw.

Good tutorial for the beginners. :clap:

YFZ450 #69

· #4 · Jul 16, 2006

another good one :clap:

you can also blip the throttle when you want to remove the needle, this will save you taking the airbox off, but you will need to sharpen up on your ninja skills to catch it in time, and it is twice as hard with fat fingers :rant2:

Duane

Discussion Starter · #5 · Jul 16, 2006

Chaos

Unplug the TPS and see how your quad runs....unless you determine which thing your "buddy" :strokin: moved to adjust the idle.

chaos

· #6 · Jul 18, 2006

Ookie dokie.. I never said he only touched the idle :icon_neutral:

ferg

· #7 · Jul 29, 2006

What happens if the TPS gets spun a little, and how can i tell if it did?

Mr. Gytr Done!

· #8 · Aug 5, 2006

Best to mark tps with a scratch to case, if it moves you will know.

hooli55

· #9 · Aug 15, 2006

I have an 06....I pulled out the needle to change the clip setting, but there is only 1 notch. I has NGN R stamped on it.

Duane

Discussion Starter · #10 · Aug 15, 2006

Most of the 06s' come with a non-adjustable needle........you would need to order a NCVQ needle froman 04 YZ450 dirt bike or a stock needle for the 04-05 YFZ to have any adjustments.

hooli55

· #11 · Aug 15, 2006

Originally posted by YFZ450alterego@Aug 15 2006, 02:19 PM
Most of the 06s' come with a non-adjustable needle........you would need to order a NCVQ needle froman 04 YZ450 dirt bike or a stock needle for the 04-05 YFZ to have any adjustments.

[snapback]470086[/snapback]

Thanks! I just put in a 168main and 45 pilot....seems to be running ok. I adjusted the idle up and it seemed to get rid of the bogging. I was just frustrated when I finally got the needle out to see that I couldnt do anything with it.

Duane

Discussion Starter · #12 · Aug 15, 2006

Well if you find you have issues in the mid range you know what needle to get...... :smile:

jdthomas24

· #13 · Oct 1, 2006

ok, i hope someone can help me, i did a cam mod and rode it and evrything was great, them i removed the vaccum housing on the subframe and the it idled ok then i put it up and t wo days later, it sucks, mid range and upper throttle, nothing there falls on its face like its starving for gas or to fat. if i mess with the tps sensor or unplug and plug it back in or even bump it, will it do that and i f so can i fix it?

hotrodchev4x4

· #14 · Oct 1, 2006

so Ego.......for those of us that havent done he leak jet yet, where is that at? i havent gone looking for it yet. i was just going to get the 35 and figure out what it looked like and find it in the carb

Duane

Discussion Starter · #15 · Oct 1, 2006

jdthomas24.....it may not be a jetting problem you're encountering. Is the battery fully charged? What year YFZ is it?

hotrodchev4x4...if I'm not mistaken the leak jet is mounted in the float bowl. I've never touched mine and luckily don't have the infamous bog that alot of people encounter. :icon_neutral:

Mustache Ride

· #16 · Nov 10, 2006

ok uh...mine doesnt have the mixture screw knob. its just a hole. what do i do?

Duane

Discussion Starter · #17 · Nov 10, 2006

ok uh...mine doesnt have the mixture screw knob. its just a hole. what do i do?
[/b]

:loser:

Do you remember posting that smiley in a reply somewhere...kinda sucks asking a legitimate question and someone's a smartass isn't it. Food for thought. :icon_biggrin:

pitjumper06

· #18 · Nov 22, 2006

wats the best way to get the top of the carb to the needle it just seems for tight in there i cant get my allen wrech in there to loosen it???

Duane

Discussion Starter · #19 · Nov 23, 2006

wats the best way to get the top of the carb to the needle it just seems for tight in there i cant get my allen wrech in there to loosen it???
[/b]

Is the carb spun? Spinning the carb is the easiest way.

pitjumper06

· #20 · Nov 23, 2006

ya its spun but how far should it be spun cause i only have it spun so far cause its hiiting on other things that are tricky to get to also

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