Leaky intake manifolds?

I bought a set of carb sync gauges off of Amazon and hooked them up to the manifolds to sync my carbs. it settles in the section where is reads that there is a valve timing issue or a leaky intake manifold. the bike is a 1978 kz1000. My question is are the gauges usually accurate and would you recommend to repair or replace the manifolds. is there another way to test for leaks?

There are two ways,the first envolves spraying a light oil/cleaner like WD-40,or carb & brake cleaner on an operating engine.

The second way:

(Using An UNLIT Propane Torch For Vacuum Leaks)

New carb holders(manifolds),along with new rubber plugs for the sync ports would be the way I'd go, as trying to repair the cracks will be time consuming. Check the rubber boots(tubing from the air filter box) if you have one, for cracks too.

I have some bad manifolds, thanks for the help.

Click > vac plugs

Good Fortune!