low vacuum when syncing carbs

[t6nis]

Hi,

I have yet another problem with my bandit. When i start to sync it, it shows low vacuum, something like 0,1. It should be 0,2-0,3. also, it kinda like stutters at low RPM, also, the 3rd cylinder does not work on idle, it starts to work around 3k rpm or so. Could this be the culprit of a weak spark? I have spark, but it looks kinda weak.

[El Gringo]

Not running at low revs is more likely to be a blocked pilot jet, i've had exactly the same problem and symptoms.

Also check the linkage springs on your carbs, the one that joins the left and right pairs of butterflys was crushed on mine and causing a lower vacuum reading on the left pair than the right

[greg737]

poor compression can really hurt the bike's idle, and since poor compression tends to be a variable thing (from one cylinder to another) it could explain the stutter.