sync carbs 10 in vac

1978 kz650 sr
1980 E1 LTD moter
Carburetor Synchronizer carb sync Gauge
When I try to sync my carbs I can onley get 10 in of vac and thats having them all the same. I used another gage to check it for acc and it was correct. Now if I tinker with them I can get 3 up to 18in and one always is about 6in of vac no matter what combo its always will have one with low. Meaning its not the same carb everytime with the 6in of vac.
Is 10in of vac acceptable of do I have a probablm. The bike idles great weak off line put runs great otherwise

Hi SR Man,

What bike are we talking about?

What vacuum measurement tool are we talking about?

Best of success
Bill

PS
Could you add your year, model and location to your signature? It helps get the best responses and it's considered real friendly too.
Bill

There are many factors that can cause differences in the readings.
You might also have a vacuum leak from a hole or crack in casings or gasket, missing parts or loose fasteners etc..
When was the last time the carbs were rebuilt/cleaned?
Have you taken the engine apart recently?
What is the history of the bike that would offer more clues?

Here is a pic of the tool I am using

what r.pm are you doing the carb sync at and as other people have also said look for an air leak.

1000 to 1500 it varies

i'd say 10 is fine as long as they are even. the last sync on my 650 with gauges like those, mine were reading 10 psi also.