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pilot jet too big?

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I have a 2012 Crf 450x  I just put on a free flow exhaust, opened the air box, removed emissions, Jetted with 165 main, NCVS needle, third position and the stock 45 pilot.   I just went to adjust the fuel screw and noticed my bike will die at two turns out and nothing happens when I have it screwed all the way in...still idles perfect.  So does that mean I need a 42 pilot jet?  My understanding is it should be set between 1 and 2 turns.  Also where ever I have it 0-2 turns out I have a little off idle bog that I really want to get rid of.  Thanks

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Not necessarily.   Lower the idle speed until it's just running.   Now repeat same adjustment....do you get the same results?


Big off idle, is that slowly rolling the throttle on or if you open it suddenly?  It is most likely the later, which is the leak jet.  Stock leak jet is a 60, you will want a 55 or 50.



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Here is my email and the response from JD jetting:


Your pilot is a little too large. Try a 45 or even a 42. 
Adjust the fuel screw this way and the bike will tell you what it wants for a pilot,
Setting the fuel screw mixture-
Try adjusting with the motor fully hot, and turning the fuel screw inwards until the idle slows or runs rough, then turn outwards 1 1/4 turns from this position. For example, if the idle slows or runs rough at 1/2 turn, then set the fuel screw to 1 3/4 turns out (1/2 + 1 1/4 = 1 3/4).
See-  http://www.pbase.com/jdjetting1/image/82894252    to understand how the fuel screw can affect the idle speed and air/fuel mixture at idle. The target range for the air/fuel mixture is near 12.5 to 13:1 at idle.

Thank You
JDJetting LLC

From: "G W" <crazybrother@hotmail.com>
To: "JDJetting@comcast.net" <jdjetting@comcast.net>
Sent: Thursday, August 1, 2013 9:22:33 AM
Subject: Sputtering

JD, i'm having a slight issue with my 2012 Honda 450x, when I'm at a constant throttle cruising at around 35-40mph the bike seems to sputter (almost like it's not getting enough fuel). The throttle is at about 1/4 -1/2 at the time, when I roll the throttle on it seems fine, like it's getting plenty of fuel... The bike is brand new and it didn't do this with the stock jetting.
(Motor is stock)
My jetting is:
Red Needle-fourth clip (middle)
165 main
48 pilot 1-1/2 turns out (R&D flexjet)
(airbox is cut only on top)
Stock header with FMF Powercore with spark arrester.
Any help would be appreciated.


Edited by crazybrother

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