Twin carb tuning

[Stewey]

Seeing as tuning involves equalising the throttle plate openings, has anyone got comments on equalising the openings via the rpm of the separate carbs as opposed to balancing the vacuums? I’m thinking of balancing the carbs with a digital strobe light on No 2 and 4 cylinders to equalise the rpm.
Just a thought!…but I have the vacuum equalisers anyway.
Thanks….Stewey

[67rustavenger]

What carbs are you working with?
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I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
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[Stewey]

Twin EMPI 34 EPC’s
Just a bit of lateral thinking!

[bsairhead]

[67rustavenger]

I usually set the throttle plates at 0.003." I set them with the carbs off the engine. Slip a feeler gauge between the carb body and the throttle plate and adjust the idle screws until you feel a slight but equal drag on the gauge on each carb.
That will at least get the engine running pretty well before you tackle the carb sync.

If you don't have a carb sync tool. Search YT for the home made carb sync tool. It involves a couple water bottles, some hoses.
I use a "snail sync tool to set my dual carbs.
_________________
I have learned over the years.
Cheap parts are gonna disappoint you.
Buy Once, Cry Once!

There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[Dodgy]

The trick is to balance the throttles just off idle, say around 1200 rpm. This ensures smooth take up. Imbalance becomes less critical or noticeable with more open throttle. If you can jerry-rig some way to hold the throttle just open at this rpm that will help loads.

There is good advice on the dual carb balancing process in the Muir 'idiot' book.
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'75 1303 (current project) owned since 1989!
'72 Squareback - full resto completed 2008 - now sold
356 Speedster kit, completed 2005 - now sold