Carb sync problem

[Sambo21]

I hooked up a JC Whitney 4-vacuum gauge unit to sync the carbs on my '97 Tourer but the needles jump around so much I can't get a steady reading at any rpm.  It seems that some sort of damping is necessary.  Anyone have any experience with this and some suggestions?  Thanks.
 

[Dag]

Two thing that will prevent the needles from jumping.
Liquid filled vacuum meters and a good length of soft wall hoses from the gauges.

Scroll down a little bit on this page: http://www.valkyrienorway.com/Tools.html

http://www.youtube.com/watch?v=aRdfIIWRXVY

[woody]

Most vac gauge sets come with some small restriction screw valves/ taps, one for each line, these are adjusted to smooth down the vibration in the carb vac (by restricting the line).
If your kit didnt have these, you could substitute some screw valves/ taps from a fish tank airline, they work just as well.
The trick is to restrict the vacuume enough to make the needles reasonably stable but not too much that it cuts off the vacuume. If the needle goes dead, you have probably restricted the line too much.

[Ricky-D]

You can use hemostats to clamp down on each line.   Works for me!