A pal of mine gave me a set of gauges to balance bike carbs. Ther are no instructions for use included. Where do the threaded adaptors screw into on the carbs? He thinks they fit on rubber hoses under carbs any thoughts?

It depends on which carbs you've got Most have a balancing nipple (which will be capped off at present obviously) attached to them that you attach the tubes onto.

The carbs are Kawasaki zxr9. fitted to a zetec engine.

On the ZX9 the take off points are on the block rather than the carb. You can see on this guide. About 4-5 pictures down, the exploded diagram. So you'd have to look more at the Zetec side of things or your adapter manifold that you're putting on I think.
Sorry I'm of no better help.

Thanks for all the replys, iwill have a go this week.