2008 yz450f jetting with dr.d full exhaust?

moto116
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moto116
Edited Date/Time 10/2/2015 9:27pm
I was wondering if anyone could help me out with jetting my 08 yz450f with a full dr.d exhaust. I live at 725 elevation, temps from 70-90. Thanks, I appreciate it
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moto116
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moto116 7/16/2012 4:19pm
7/16/2012 4:19pm
Yes I did, but it didn't have different specs for different altitudes.
moto116
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moto116 7/16/2012 4:20pm
7/16/2012 4:20pm
also, can I change the needle clip position without removing the carb from the bike? I know I can change the main and pilot without removing the carb but wasn't sure about the needle clip

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nickvalve
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nickvalve 7/17/2012 8:44am
7/17/2012 8:44am
The 5 valve head almost eliminates any rejetting up to 9,000 ft. We have found many that require a much richer pilot jet [ in the 45 to 50 size] even at sea level. Typically Dr.D exhausts do not require any major re-jetting.
mxryder231
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mxryder231 7/17/2012 8:50pm
7/17/2012 8:50pm
i have a 2008 yz450f, with a dr.d stainless steel header with a dr.d carbon exhaust. at 1000 feet alt. at pump 91 gas. i am running a 50 pilot, ncyq needle second clip 168 main. re timed the squirt on the acc. pump. and a stock #25 banshee pilot which is a 42 leak jet. i run a cageless air filter cage and a twin air filter. hope this works.
nickvalve
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nickvalve 7/18/2012 9:22am
7/18/2012 9:22am
50 pilot is fine / do not know what a ncyq needle spec is for comparison purposes against the stnd. nflr / do not think that banshee jet will work properly as opposed to the stnd. 55 leak jet / the 168 main may or may not be too rich with that needle , If it were me , I would go back to stock jetting and set the pilot jet size for 1 1/2 to 2 turns out on the fuel screw. 1,000 feet isnt going to make any difference , we routinely go from sea level to 3,000 feet with no adjustments at all . [ Glen helen to Comp. Park ] . Side note : Be sure to re-pack that carbon can regularly , if it blows out packing it can crack .
mxryder231
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mxryder231 7/18/2012 6:50pm
7/18/2012 6:50pm
ncyq is the next richer needle to stock. the banshee pilot and the kehien leak jet are the same thing. and i got my information to a really really known person who has worked for yamaha. i know this all may sound like bull shit, but i have absolutly no bog or hesitation on my bike. the second clip postion on the needle with that main works bitchen. the guy who gave me this info knows mike guerra who runs all yamaha racing at cypress.
eddieearl
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eddieearl 10/2/2015 9:27pm
10/2/2015 9:27pm
mxryder231 wrote:
i have a 2008 yz450f, with a dr.d stainless steel header with a dr.d carbon exhaust. at 1000 feet alt. at pump 91 gas. i am...
i have a 2008 yz450f, with a dr.d stainless steel header with a dr.d carbon exhaust. at 1000 feet alt. at pump 91 gas. i am running a 50 pilot, ncyq needle second clip 168 main. re timed the squirt on the acc. pump. and a stock #25 banshee pilot which is a 42 leak jet. i run a cageless air filter cage and a twin air filter. hope this works.
Two questions:
1. What's the difference between a 50 pilot and a #25 banshee pilot 42 leak jet?
2. How do you re-time the accelerator pump?
Thanks,
Troy

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