08 YZ450 carburetor problem please help

TsmithMX
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122
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Chico, CA US
9/20/2016 11:09pm
The carb is clean first of all. When the bike is cold and I put the bike in gear to roll away, it dies. Or when it's idling, before it's fully warm, And i Blip the throttle, it cuts out and dies. What's going on? Thanks. I only have this problem before the bike is fully hot
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Paw Paw
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12/24/2011
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Benton, LA US
9/21/2016 5:06am Edited Date/Time 9/21/2016 5:06am
The bike is very lean.
Clogged pilot jet, pilot jet size too small, fuel screw not set correctly are the most likely causes.
You may need to go up 1 jet size on the pilot jet and then readjust the fuel screw.
These bikes want to be warm before taking on a load.

Paw Paw
pete24
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Marlborough, MA US
9/21/2016 6:43am
i had a new 08 yz 450 and the stock pilot is wicked lean, also sounds like yours is clogged, put a new #45 in it you will be surprised how much better it is
TsmithMX
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122
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5/7/2009
Location
Chico, CA US
9/21/2016 8:07am
Paw Paw wrote:
The bike is very lean. Clogged pilot jet, pilot jet size too small, fuel screw not set correctly are the most likely causes. You may need...
The bike is very lean.
Clogged pilot jet, pilot jet size too small, fuel screw not set correctly are the most likely causes.
You may need to go up 1 jet size on the pilot jet and then readjust the fuel screw.
These bikes want to be warm before taking on a load.

Paw Paw
Thanks!
TsmithMX
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122
Joined
5/7/2009
Location
Chico, CA US
9/21/2016 8:08am
pete24 wrote:
i had a new 08 yz 450 and the stock pilot is wicked lean, also sounds like yours is clogged, put a new #45 in it...
i had a new 08 yz 450 and the stock pilot is wicked lean, also sounds like yours is clogged, put a new #45 in it you will be surprised how much better it is
I'll try that, I really appreciate it

The Shop

lumpy790
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9/18/2007
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York, SC US
9/21/2016 5:54pm
Is the bike stock? What mods have been done?
TsmithMX
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122
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5/7/2009
Location
Chico, CA US
9/21/2016 5:57pm
lumpy790 wrote:
Is the bike stock? What mods have been done?
Completely stock
lumpy790
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York, SC US
9/21/2016 6:34pm
I have an 08 and a exhaust really brings it alive! Stock muffler is extremely restricted
RyanLester761
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2/7/2007
Location
El Dorado Hills, CA US
9/22/2016 2:57pm
I had this problem before. I noticed the header pipe would glow red at idle. Would you guys agree that's another indicator of a lean condition? Richening the pilot helped both issues for me.
lumpy790
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9145
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9/18/2007
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York, SC US
9/22/2016 5:41pm
I had this problem before. I noticed the header pipe would glow red at idle. Would you guys agree that's another indicator of a lean condition...
I had this problem before. I noticed the header pipe would glow red at idle. Would you guys agree that's another indicator of a lean condition? Richening the pilot helped both issues for me.
Modern 4 stroke red exhaust is 100% normal.

I just realized .... You say it only does this when its cold. Mine does the same thing when you turn the choke off and it's still cold. You really need to warm these things up for 30 seconds blipping the throttle.

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