Jetting 101. - Yamaha YFZ450 Forum : YFZ450, YFZ450R, YFZ450X Forums

**Duane** · 07-07-2006, 06:45 PM

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.

[attachment=4730:effects3.gif]

chaos · 07-15-2006, 11:09 PM

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

Toadz450 · 07-15-2006, 11:18 PM

Quote:

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.

YFZ450 #69 · 07-15-2006, 11:20 PM

another good one

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

**Duane** · 07-16-2006, 12:08 AM

Chaos

Unplug the TPS and see how your quad runs....unless you determine which thing your "buddy"

moved to adjust the idle.

chaos · 07-18-2006, 09:03 AM

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

ferg · 07-29-2006, 12:06 PM

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

Mr. Gytr Done! · 08-05-2006, 03:31 PM

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

hooli55 · 08-15-2006, 03:28 PM

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** · 08-15-2006, 05:19 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.

hooli55 · 08-15-2006, 07:01 PM

Quote:

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** · 08-15-2006, 07:03 PM

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

jdthomas24 · 10-01-2006, 02:09 AM

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 · 10-01-2006, 06:15 AM

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** · 10-01-2006, 10:21 AM

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.

Mustache Ride · 11-09-2006, 11:53 PM

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

**Duane** · 11-10-2006, 06:30 AM

Quote:

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

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.

pitjumper06 · 11-22-2006, 06:41 PM

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** · 11-22-2006, 07:00 PM

Quote:

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 · 11-22-2006, 07:36 PM

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

07-15-2006, 11:20 PM	#4 (permalink)
YFZ450 #69 Senior Member Join Date: Aug 2004 Location: Australia Posts: 4,741	another good one 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 __________________ pfft.

07-16-2006, 12:08 AM	#5 (permalink)
Duane Senior Member Join Date: Dec 2004 Posts: 13,909	Chaos Unplug the TPS and see how your quad runs....unless you determine which thing your "buddy" moved to adjust the idle. __________________ My photography website---->http://www.pbase.com/duane_va "Live as if you were to die tommorow. Learn as if you were to live forever." -Ghandi

07-29-2006, 12:06 PM	#7 (permalink)
ferg Member Join Date: Sep 2004 Location: Seattle, WA Posts: 98	What happens if the TPS gets spun a little, and how can i tell if it did? __________________ 2005 SILVER YFZ450 LTE Dual exhaust K&N Cam-mod Dyna-Tek Ignition -6 Flywheel Laker Custom Plastic Some BLING here-and-there "Got Twins?"

08-05-2006, 03:31 PM	#8 (permalink)
Mr. Gytr Done! Senior Member Join Date: Jan 2006 Posts: 162	Best to mark tps with a scratch to case, if it moves you will know. __________________ Sponsors- Jimmy's Cycle Sales, Rons Motorworks. 2006 YFZ 450,GYTR front bumper ,a-arm gaurds, Prm rear and belly skid, Prm grab bar, Precision stabilizer, Moose hand gaurds, Pro design kill, Pro Armor Fat Peg nerfs, Holeshot XCR on Douglas rims. 2-1996 Banshee's, 1997 Honda Foreman 4x4. And always remember....when life hands you lemons, ask for tequila and salt and call me

08-15-2006, 03:28 PM	#9 (permalink)
hooli55 Member Join Date: May 2006 Location: Cali Posts: 52	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. __________________ '06 fo fiddy SoCAL Pro-Flow Intake w/o lid or baffle 168main 45pilot jet Holeshot Gncc 20x10 rears, 21 HD's in front 1.5" front wheel spacer's Pro Armor Nerf's, Armadillo Armor Big ZeRo OnE Flag Pro Taper Mid SE Bars w/spider grips

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07-15-2006, 11:09 PM	#2 (permalink)
chaos Senior Member Join Date: Sep 2005 Location: long island,NY (sucks) Posts: 3,207	Is the TPS the thing the pen is on? (I think thats the idle) Or is the where the arrow is? Im confused!

07-18-2006, 09:03 AM	#6 (permalink)
chaos Senior Member Join Date: Sep 2005 Location: long island,NY (sucks) Posts: 3,207	Ookie dokie.. I never said he only touched the idle

08-15-2006, 05:19 PM	#10 (permalink)
Duane Senior Member Join Date: Dec 2004 Posts: 13,909	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. __________________ My photography website---->http://www.pbase.com/duane_va "Live as if you were to die tommorow. Learn as if you were to live forever." -Ghandi

08-15-2006, 07:03 PM	#12 (permalink)
Duane Senior Member Join Date: Dec 2004 Posts: 13,909	Well if you find you have issues in the mid range you know what needle to get...... __________________ My photography website---->http://www.pbase.com/duane_va "Live as if you were to die tommorow. Learn as if you were to live forever." -Ghandi

10-01-2006, 02:09 AM	#13 (permalink)
jdthomas24 Senior Member Join Date: Aug 2006 Location: Texas Posts: 987	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? __________________ if i did not know any better, i would think you are eyeing me Fox Dcs shocks, Lonestar Dc4 Arms,Burgard Stem and Subrame, Hiper's with razrs all around, Elka dual rate rear, houser XC and LT linkage,Carb Mod, Cam Mod,K-Fab radiator spill tank and propegs with hellguards, Gusset frame,Rossier full exhaust ,GYTR frame skid and swinger 2 piece skid,K&N filter with outerwear,AC bumper, PRM grab bar,LSR axle with honda sprocket hub, flexxbars, 250R throttle, WR kit,

10-01-2006, 06:15 AM	#14 (permalink)
hotrodchev4x4 Senior Member Join Date: Jun 2005 Location: Washington Posts: 128	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

10-01-2006, 10:21 AM	#15 (permalink)
Duane Senior Member Join Date: Dec 2004 Posts: 13,909	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. __________________ My photography website---->http://www.pbase.com/duane_va "Live as if you were to die tommorow. Learn as if you were to live forever." -Ghandi

11-09-2006, 11:53 PM	#16 (permalink)
Mustache Ride Senior Member Join Date: Sep 2003 Location: Glendale, AZ Posts: 827	ok uh...mine doesnt have the mixture screw knob. its just a hole. what do i do?

11-22-2006, 06:41 PM	#18 (permalink)
pitjumper06 Senior Member Join Date: Feb 2006 Posts: 351	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??? __________________ 2006 YFZ450/Blue lifes a w00ter.........................go out and RIDE!!!! U sink it u die

11-22-2006, 07:36 PM	#20 (permalink)
pitjumper06 Senior Member Join Date: Feb 2006 Posts: 351	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 __________________ 2006 YFZ450/Blue lifes a w00ter.........................go out and RIDE!!!! U sink it u die