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Discussion Starter · #1 ·
I need some help with trouble shooting getting my jetting right with the mods in my signature. Right now when I give the throttle a blip it chokes out and try's to die. When The blip is pressed there is also some popping. The elevation I am testing at is 500 feet.

How much should I change jets for riding at 3k-6k?
 

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Discussion Starter · #3 ·
Is that for sea level or higher elevation? Thanks also. I will give it a shot.
 

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Discussion Starter · #4 ·
Ttt
 

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Bogging...

I need some help with trouble shooting getting my jetting right with the mods in my signature. Right now when I give the throttle a blip it chokes out and try's to die. When The blip is pressed there is also some popping. The elevation I am testing at is 500 feet.

How much should I change jets for riding at 3k-6k?
Having the same issues here with my 04 yfz 450. Idles perfectly, and responds well if I ease through the throttle, but if I stab it, it bogs to the point of dying. Even a light jab on the throttle and it bogs.
It's got Dasa exhaust, ESR intake, zip tie mod, cam mod. 172 main 48 pilot 2.5 turns on a/f screw. Stepped up to a 50 pilot, but same issue. I'm in Pismo Beach, sea level.
Will simply turning screw in a 1/4 turn or so eliminate bog?
 

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Having the same issues here with my 04 yfz 450. Idles perfectly, and responds well if I ease through the throttle, but if I stab it, it bogs to the point of dying. Even a light jab on the throttle and it bogs.
It's got Dasa exhaust, ESR intake, zip tie mod, cam mod. 172 main 48 pilot 2.5 turns on a/f screw. Stepped up to a 50 pilot, but same issue. I'm in Pismo Beach, sea level.
Will simply turning screw in a 1/4 turn or so eliminate bog?
Try a 45 pilot jet and 1 full turn from fully seated on the fuel screw.
 

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A compilation of posts from others. I too have been trying to help get mine jetted properly. :
FYI - Backfiring was caused by the missing Fuel Mixture Screw. My scotts T handle fell out so I bought the Zip-Ty and it is a better screw... Don't know about the woodward screw.

First I installed a 190 jet and it shot flames out my pipe about 9 inches long... and that was with a spark arrester/quiet core installed.

So I went back down to a 180. So hear are my specs now...

Main: 180
Pilot: 48
Needle: Stock, Clip at stock position
Fuel Mixture: Zip-Ty at about 2 turns

Runs perfect! Pipe doesn't glow much anymore and no flat spots. Strong all the way through, especially in the upper RPMs. I would much run it rich than lean... save the engine over extreme performace

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BB hmf slip on
300ft
Uni filter no lid
ncvq on second clip from top
170 main and 45 pilot 2 turns out

Runs great i love this pipe not to mention the candy blue
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cam mod
HMF full system
pro design pro flow foam w/ lid off
172 main
stock needle
air mix 2 1/2 out
stock pilot
at 1000 .ft in oklahoma
do yall thank im runen lean? with the stock pilot. btw there is no poping
when i let off the throttle. it seems real crisp which isnt a bad thang.

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lright... i got a full HMF exaust with K&N no lid.. im ruunin a 168 main 48 pilot with 2 1/2 turns out on air mixture screw at 900 feet hope this helps

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HMF slip on
K & N filter
No lid
2200 ft.
172 main
45 pilot
NCVQ needle 3 clip

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hmf full exhaust. stock clip setting..185 main. 48 pilot.no airbox.kandn..runs like a champ.
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2007 HMF full system.
Velocity Air Filter w/ ab lid off.

175 Main
45 Pilot
NCVQ needle w/ clip in 4th position.
Fuel Screw 2 turns out.
Elevation is approximately 1100'...SW PA

So far everyone who has ridden it has said one thing...."WOW"

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06 full hmf ballance

k&n with no lid

cam mod

168 main

45 pilot

gytr needle 4th clip

2 turns out

900 ft wisconsin

this set up just rips but might bump the main to 170 this weekend
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05 yfz
HMF Ballance full system.
Stock Intake and Filter
Main jet 180
Pilot 48
forgot where needle and mixture is set

Runs a tad rich, but she rips on top and thats what I like anyways
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HMF Sport Full Exh.. Cam mod, Lid removed..

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4300 Ft
45 pilot
Stock Main
GYTR Needle #3
Screw @ 2.75 turns

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1200ft
HMF slip-on
ESR Intake
12.5:1 CP piston; zip tie mod; cam mod
175 main, 48 pilot, 35 leak, NVCQ 4th clip, f/s 3 turns out

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05 yfz 450
-stock engine
-a dozen or so holes in the air box llid
-fmf powerbomb header and hmf slip on
-moose foam filter
--carb settings for 30-40 degrees temp, 900ft? elev.:
-jd jet kit
4th clip on needle that came in the kit
36 main
45 pilot
-R&D remote air fuel screw set at 2 1/4 turns

..going to do the spark plug test tomorrow since its gonna be 20+/- degrees untill end of febuary. i expect to go up to a 38 main and 1 3/4 a/f mix... maybe haha

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Here at sea level (Long Island NY), I have the HMF Comp-Series slip on, Lid off with K&N air filter/Modquad adapter. Jets that worked perfect for me are: 168 main jet, 45 pilot, NCVQ needle clip#2. No backfire or sputter on accel/decel and pulls hard through the gears (Thanks Terse! Man knows his ishhh!)

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2008 YFZ450 @ sea level and warm atmosphere

HMF slip on
Quickshot 2
Cam Mod
Zip-tie Mod
Stock Intake w/lid off

Took a bit to dial this in right (with the help of you guys!! Thanks!):
48 pilot
165 main
40 leak
NCVQ needle at 3rd clip
air/fuel screw at 2 turns out

The Quickshot and zip mod probably got rid of the bog the most.....I started at 45 pilot but it idled high once it got hot and backfired on decel.....after being told to go up to 48 I did and BINGO! I FREAKING LOVE THIS QUAD NOW!!!

Still has a SMIDGE of backfire.....but don't know how much closer I can get without messing it up
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