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Old 07-21-2006, 04:15 AM   #1
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Default SH Engine Help?? 3 needle carb

I've made a noob mistake, i've got a PT2004-XB1 SH Engine, this model has three needles in the carb, I thought i was adjusting the normal low end needle to tune it but i was actually adjusting the third needle(i've been told its a fine tune needle for the low end).

I've checked the SH website but it doesn't say anything in the tuning instructions about it. Does anyone know how many turns to set it back to factory, or how to tune this needle properly??

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Old 07-21-2006, 05:20 AM   #2
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put it back to flush
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Old 07-21-2006, 06:58 AM   #3
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This third needle is known as the "mid screw". I would recomend finding out what the factory setting is for the low and mid screws and re-tuning from there. The reason for the mid screw is to allow the racer to change the poing where the low needle "turns off" allowing full flow from the high speed needle. If you were to want to adjust the mid screw, you would want to turn the low needle the same amount in the oposite direction of the mid screw. i.e., if you want the move the mid 1/2 turn out you must also turn the low 1/2 turn in to keep the amount of fuel the low needle allows through.

Hope that helps.
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Old 07-21-2006, 10:42 AM   #4
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Berkky: Do you mean the screw needs to be flush on the outside of the carb? or flush on the inside i.e the pin sits flush with the inside of the wall of the carb.

Davidka: Thats what i'm not sure of, the factory setting for it, their website doesn't have much technical support
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