weber tuning, questions Options

[r_towle]

ok,
So I have one rich and one perfect plug on one side...

I will use the idle mixture screw to adjust this condition...

What is the air bypass screw for, where do you guys set it, and how does it change the way the carb tunes??

I was having some sooty exhaust, so I checked the floats..perfect..if not just a tad lean...11mm which is ok with me...

Rich

[rhodyguy]

as stated. initially set all 4 of the bypass the same. closed, open 1/2 turn, just make sure they are the same, and foget them until latter in the tunning proceedure. set each idle/air mixture screw the same, try 2 1/2 or 3 turns out. don't get excited guys, this is just a common starting point. just try this...with everything in place, back one idle adjust screw off its stop, turn the idle up with the remaining one, and check the flow with the throats facing you on each carb. if they are not flowing equally, adjust the droplink on the non idle stopped carb to balance the flow. something often overlooked...there are little orings under the idle air mixture screw springs. check their condition. they get brittle and cracked. now...flowing the same? turn the idle down. gently seat each idle/air mixture screw, one at a time!!! the idle will fall off and you will hear a snapping out the exhaust. turn it back out til' the idle smooths out (at this point i turn it out the tiniest bit more). do the remaining 3 for a smooth idle. if you want to, you now check the flow rates for each throat. this is the point where you would equalize all 4 of them with the air by-pass screws. of course, your timing and valves are spot on right?

k