The Stovebolt Site Forums The Shop Area Engine Shop DUAL CARB SET UP

You guys are weenies, I have a 4 cylinder motorcycle with 4 sidedraft carbs on it, one for each cylinder. It's not that hard to keep tuned, you just need a vacuum gauge (it doesn't have balance tubes). With a 2x carb set up you need a flow meter to synch it right but you can get very close by listening to the venturi whistling and matching the pitch between the two. The idea is to match the air flow between all the carbs at two points- 2000 rpm and idle, in that order. Then just set the idle screws at the same point for good idle mixture and you are good to go. When you first install the carbs you need to change the power valve so it opens at half the vacuum than the original one did so you get a rich enough mixture.