any tips for tuning weber 34ict? Options

[JOE M]

Curious about how to set the carbs up.The timing is close but may be out slightly.I started by turning the air mixture screws all the way in and than backing both off by 2 1/2 turns to start. I let the car idle and than I move 1 side until the car runs rough than back off the other way about 1/2 turn.I did the same for the other side. It runs ok but pops through the exhaust every now and than.It gets better when I take the throtle linkage off.I think my biggest problem is seting the idle speed screw. Is there something I should do prior to starting any other alignment?I read the procedure but I am stumped. What typically causes it to pop through the exhaust?I did check the vacum on both sides and they are real close ( within 1 of each other).

[aircooledtechguy]

Here's how I sync duals. . .

First ensure all your linkage is connected and symmetrical (cross bar type linkage) you want your drop links to be as close to straight up and down as possible as well as even between the left and right side. If one is at a severe angle compared to the other, you will have problems because one carb will always lag or lead the other later.

Then, with engine running, disconnect one of the linkage arms so that the carbs are totally separate and sync the air flow through them with a syncrometer.

Then reconnect the linkage arm and tighten it into place. I find it better to do this with the engine idling so I can hear changes as I connect the link. Re check with a syncrometer to ensure they are still even at idle and exactly where they were before the linkage was attached. If anything has changed, adjust the linkage arm to get it even again at idle.

Then put your finger on one carb throttle arm and closely watch the other while you gently blip the throttle with the other hand where the cable attached (that is really important because if you use another part of the linkage to blip the throttle, it could be twisting and flexing the linkage in a way that it does not normally flex while driving). See/feel that both arms are beginning to move at the EXACT same time. This will ensure that you have a smooth throttle response off idle.

Next with the engine OFF, ensure that at WOT both throttle arm hit their stops at the same time. If they don't, the Geometry of your linkage arms is off and you will need to re-adjust things so that they can both get to WOT at the same time AND idle at the same time.

Once you have the linkage perfect, then you can move to the mixture screw fine tuning. I prefer to do this with my eyes closed so that I can concentrate on the engine speed better, but that's just me (IMG:style_emoticons/default/smile.gif)

Hope this helps. . .