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Discussion Starter · #1 ·
Here are the sheets from my dyno today. Can I get some help with what I should do about my mid rpm A/F.

Build

SE performance heads, forged pistons (10:5), SE-258 cams, Rivera HSR42, and some Samson street sweepers. ( I know I need a 2-1 )

The jetting is: Pilot 25, screw 1 1\4 turns, main 160 and stock needle and acc. pump. The clip is on the top position.

Thanks
 

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Try moving the clip on the needle down a notch. The taper of the needle jet along with the main jet size controls the mid-range. All of the jets over lap somewhat but the position of the needle will effect the midrange the most. The main jet effects full throttle and the pilot jet effects idle and just off idle.
 

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Discussion Starter · #3 ·
Thanks for the reply. I already know the parts of the carb and was just looking for some suggestions by some other folks. I plan on getting a leaner needle and putting a bigger main in.

Anyone have some other thoughts.

Thanks
 

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Arrogant Bastard
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flyin hawaiian said:
Thanks for the reply. I already know the parts of the carb and was just looking for some suggestions by some other folks. I plan on getting a leaner needle and putting a bigger main in.

Anyone have some other thoughts.

Thanks
Sounds about right for your rich mid/lean top end. You might also look at increasing your acc. pump stroke duration. I haven't dealt with this specific carb before but you should be able to get a different actuator arm for the acc. pump. This might help with the dip in the torque and AF curves as you transisition from the pilot to the needle jets.

Joe
 

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IronButt
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Here is a quick test, when they make the pull use a board and hold it about 4 inches off the end of the pipe. You will see the curve flatten out, I have dynoed with that pipe a issue look to have is over scavaging. IE no baffle. And I would check pump stroke it may be on too long, I start at 1/3 and tune from there.
 
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