Carb Balancing explained

[Gerrit]

Is the result of carb balancing, getting the butterflies to open & close to the same position every time. ?

I have read so many posts about carb balancing, but I think I am missing something, as it seems that the carbs must be balanced even when a slight adjustment is made to the mixture screws...why?

When the throttle opens, the butterflies open....

Everytime I have the carbs off, I adjust the "balance" using a feeler guage on the butterflies, thus getting them to upon in unison.

I too a long plank, glued down some clear tubing up & down the plank and filled this with oil. The idea is to hook either end of the tubing to the vacuum tubes, and do the carb balacing...I assume the oil levels should be at the same level on both sides, and the carbs are balanced?

Your thoughts ?

Gerrit

[Phil-VTwin]

What are doing is balancing the air flow into the cylinders so that each has the same amount when ignition occurs.
Measuring the vaccuum is one way of doing it as the inlet stroke creates this and depending on how much air is sucked in it can be measured but i use an air flow meter on mine in the trumpets and adjust so they both read the same at idle.

Once done then adjust the mixture and check 'air flow' again.

[sirch345]

The vacuum test for balancing the carbs has to be the most accurate IMO, using a feeler gauge would probably be almost as good on brand new carbs, but I doubt is would be as accurate on used carbs.

I'll be interested too hear after you've set the butterfly's with the feeler gauge, then you use the carb balancer does it show up a difference

Yes you are right in thinking both oil levels on your balancer should be showing the same, if the carbs are in balance,

Chris.