I calibrate my guages before i synch. I pick the easiet carb to reach and plug each guage into it and adjust the guage so that all read the same. Then I hook each guage up to the carbs. Whan you have them all reading the same, the carbs are synched.
I calibrated my gauges with a big ole syringe thingy:
Pulling up to the 60cc line, showed 20" on the gauge and was very accurate, the exact same reading being repeatable over and over. Checking the gauges to one another, showed them to be within a "tick mark" of each other, which was negligible enough to not have to even bother incorporating into the carb synch process - gotta love German engineering!
(the gauges were German made)I'm kinda surprised so many of you are hesitant to make a set of your own, since it was really sooooo easy! I just copied the Hondaline gauge set visually, especially noting the needed gauge range (30" Hg vacuum) and that it needed some kind of damper valves. I ordered the parts off on feeBay over a week and once they all arrived, made the whole setup in an evening with a few beers.
I don't have to fool with bottles filled with liquid and stuff and get to show it off as something that I made, which is pretty fun. (my neighbor didn't even believe me. . .lol) The set in compact enough that I literally put it in one of my saddle bags and went over to my friend's house to help balance his carbs, too. (and wOw!, do balanced carbs make a huge difference in how well your bike runs!)
Oh, and I also made a remote mini-gas tank to aid in carb synching from old weed-whacker parts I horse traded from my neighbor, a day or two after the manometer project, too. . . . he he he.
DIY - FTW !!!