Carb bench synch

[nj1639]

ipad picture quality sucks but you get the idea.
Borrow two straight pins from the missus. Get them with the little do dads on the end as they're easier to find when you drop them. Here we have yellow stars.
Open the butterflys and center one pin in the bottom of each opening. Close the butterflys and then adjust the center screw to where each butterfly has the same grip on each pin.
Done? return the pins and maybe she won't notice any grime that may have been transferred.

 

[oldskoolcarbs]

also reference the butterflies to your bleed port holes

 

[gggGary]

You get a gold star for this idea NJ!
Make it two gold stars!

 

[nj1639]

Grimey gold stars lol.
Thanks G!

 

[Paul Sutton]

An alternative method is to use that very fine copper wire from a mains cord. This is softer than the butterflies so allows you to pull it through and make the balancing adjustments based on the amount of drag felt. I use a fresh piece of wire for each drag as the butterflies have sharp edges and will wear the wire a little each time. I did mine this way and then recently made a U-tube manometer and found I was only out by about 1cm.

 

[5twins]

I don't find the need for any sort of "feeler gauge". I hold the carb set up to a good light and observe the size of the "crack" of light showing around the plate edges. First, I back the idle speed adjustment screw off all the way so the plates are completely closed. If out of sync, one plate will show no light around the edges, the other will. Then it's a simple matter of playing with the sync adjustment screw until both plates are completely closed. Go too far past the perfect sync adjustment point in either direction and one of the plates will begin to open again and show light around the edges. Once synced, I turn the idle speed adjustment screw back in until both plates just crack open a hair.

 

[xschris]

I also do the 5twins method for bench syncing with very good results. I only need minor adjustments with the mercury stix when I do my final sync.