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Discussion Starter #1
Hello, I have a 05 trx 400. I moved from 2,500 feet and was running a 38 pilot and 148 main jet. I now live and ride at 9,200ft. I went to a 35 pilot and when I turn the screw for idle fuel ratio it doesn’t make a difference to the engine no rpm raise or drop even screwed all the way in.
I put in a 140 main and it runs good but the plug looks lean so I will try a 142.
Any suggestions on the pilot jet sizing.
 

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Recommended high altitude carb adjustment is #38 pilot jet with fuel screw turned in one full turn from the low altitude setting and a #142 main jet

If you do not know what the fuel screw setting was before you adjusted it, the initial setting from the factory was 2 turns out from lightly seated - this is the setting used to start the engine and run till it's at operating temp before making the final setting for the best idle
 

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Discussion Starter #4
Can you provide a link to a ebay auction where I could buy a 142 jet. I’m not sure what series Keihin carb this is. Thank you very much
 

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Discussion Starter #6
Is there anyone who makes a aftermarket air fuel idle screw. I have the Honda special screw driver but can’t seem to turn the screw once the carb installed.
 
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