Or maybe I am blink and there is a hidden menu which allow you to set a 2/2 ,a 3/4 .

Haven't heard that term before but if it means 'dumfounded' or 'wondering what the heck Yamaha did this time' then, like you, me and many others, we are all 'blink'.

A wise person once said 'nothing is truly hidden if you know where to look'! Ok, I don't really know if anyone said that but it often seems to apply for the Montage.

There are two related, but different, things at play: tempo and time signature.

You will find 'tempo' on the 'Utility -> Settings' screen where you can set a value from 5-300 or 'tap' your own tempo. You can also specify 'Beat': 1/16, 1/8, 1/4, 1/2, whole and some other settings that determine WHEN  the 'click' will sound and WHAT it will sound like.

You will find 'time signature' on the 'Play / Rec -> Pattern' and 'Play / Rec -> 'Song' screens. The value will be hashed out and can't be changed until you press 'Record' to record a new song or pattern. You can't change the time signature of an existing song or pattern.

Bad Mister explains it in these replies:

We don’t call this a Sequencer (although in the common language one might refer to any device that records MIDI a Sequencer) we are purposefully stressing that this is not built to be a record and then edit after-the-fact device. It lends it self as a great scratchpad Recorder.

https://yamahasynth.com/community/montage-series-synthesizers/performance-recorder-changing-tempo-and-time-signature/#post-122374

https://yamahasynth.com/community/montage-series-synthesizers/time-signatures-issue-resolved/#post-27539

Yamaha sometimes uses tempo, beat and time signature interchangeably and it can be confusing to straighten it out.

Also things like motion sequences and arps can be sync'd to the 'beat'.

1. you specify the time signature BEFORE you begin recording

2. once recorded the time signature of a song/pattern can NOT be changed on the instrument - a MIDI editor could

3. you CAN create a pattern 'chain' of up to 8 Scenes with each scene having its own time signature.

If  you are not already 'blink' enough Bad Mister explains how to create such a 'measure framework' in this thread:

https://yamahasynth.com/community/modx-series-synthesizers/full-sequencer-on-modx/#post-104896

That thread has info you won't find anywhere else so you may want to make a copy for yourself or at least bookmark it. You can find MANY other threads for this topic by searcing for 'change time signature'.

Sorry for the length and multiple 'doc' references but the topic is a lot more complex and intertwined that it may appear.

Thank you Toby. Yes , I know now that I can set a time signature thru pattern record and save it with the performance. Not direct but better than noting. Again it show that Yamaha engineer underrated the function of a metronome as they did for the SP knob flashes. My goal is not for recording but have a metronome associated with the performance at the right signature. About blink, that is funny, I wanted say blind, but maybe I am contaminated by the blinking SK. but then I think you find a nice definition of what could be blink in this context!