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Redline / Top End Performance is at www.webercarbs.com. I no longer run this carb, but got plenty of good service from mine for the years I had it.
First adjust the valves to .018" lash cold, or .016" lash hot. Theoretically these should come out the same; in practice hot is more accurate.
Next set timing for as much advance as possible without pinging. Ensure the advance actually works.
Now for the carb tuning... See the Redline site for float levels, for a start -- that's critical to everything that follows. After that:
Idle jet selection:
Set idle for 900-1000 RPM. Choose the idle jet that gives best idle with the mixture screw 1 to 2 turns out from fully closed. If you need to turn out more than that, the idle jet is too lean; in more than that, it's too rich. Keep readjusting the idle speed as you test this. After you find the best jet, set the mixture for fastest/smoothest idle and finally reset the idle speed one more time.
Primary main jet selection:
Drive the car at a steady mid-range speed (let's say 3000 RPM) without accelerating. Choose the smallest jet that doesn't surge. The accelerator pump should prevent bogging on acceleration with this jet. If it doesn't, it needs repair or adjustment for more stroke.
Secondary main jet selection:
Smallest jet that gives smooth running at wide throttle openings, with the secondary open (duh). This is typically one size smaller than the primary main jet.
Secondary idle jet selection:
The smallest jet that doesn't stumble when you open the secondaries slowly.
There's a correlation between timing and mixture... you can jet slightly leaner if you run more advance, but too lean will cause you to back off the timing. You may have to ping-pong a few times to get the right balance.
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