03-12-15, 03:54 PM
As you observe the screw in between No 1 carb and No 2 only moves No 1 butterfly. Also between 3 and 4, only 4 moves.
The screw in the middle (between 2 and 3 carbs) moves 1 and 2 relative to 3 and 4.
The idea is you balance 1 and 2 to each other. Balance 3 and 4 to each other. Then use the centre screw to balance 1/2 to 3/4.
Blip the throttle a few times and thensome final tweaking is usually needed to get the best reading. I have not looked at the link that was posted so I am probably just repeating some of it!
The problem of one being way too much vacuum could be caused by a leaking diaphragm as that would stop the slide lifting. Easily checked by removing the top cover held by two screws. Also check that the slide is moving freely. You could swap the diaphragm and slide from your old carb or from one of the other spare spare carbs.
The screw in the middle (between 2 and 3 carbs) moves 1 and 2 relative to 3 and 4.
The idea is you balance 1 and 2 to each other. Balance 3 and 4 to each other. Then use the centre screw to balance 1/2 to 3/4.
Blip the throttle a few times and thensome final tweaking is usually needed to get the best reading. I have not looked at the link that was posted so I am probably just repeating some of it!
The problem of one being way too much vacuum could be caused by a leaking diaphragm as that would stop the slide lifting. Easily checked by removing the top cover held by two screws. Also check that the slide is moving freely. You could swap the diaphragm and slide from your old carb or from one of the other spare spare carbs.