carbmate

To use the Carbmate there are 2 methods:

1. Disconnect the balance pipe from one of the inlet manifolds and then connect one pipe from the Carbmate to the balance pipe and the other to the manifold. You would need to measure the size of the various pipes and buy suitable adapters. See here: https://www.youtube.com/watch?v=5wXfiVBO2Uc

2. Clamp off one of the short rubber hoses at the end of the balance pipe using a brake line clamp tool. Remove the 2 small screws fitted to the top of the inlet manifolds and screw-in 2 barbed adapters that you can then connect the Carbmate pipes to. You can leave these adapters in place and use some closed-end silicone pipes to seal them off.

There are various adapter here: https://tecmate.com/carbmate-rotax-kit/

https://www.rotax-owner.com/en/videos-topmenu/product-reviews/62-carbmate

Hello Benny,
0. For technical advice see the MML from ROTAX, the informations and Videos also are very helpful was given above!
1. Carburator synchronisation means to adjust the intake air pressure (throttle valves) identical at both carburators while the engine is running idle.
2. By measuring the air pressure (aprox. - 0-5 bar = 7,5 psi) you can see if there are differences between the adjustments (first of all the throttle valves).
3. The intake air pressure  is an indicator for the amount of sucked air - not more - identical intake air alone does not guarantee a smooth running!
4. For a smooth engine running there are a lot of other factors needed, but first of all the intake air (pressure = amount or air) is the most important and second the amount of fuel into the sucked idle air.
5. The amount of fuel (by idle) is regulated by the idle mixture screw. While adjust the throttle valve it makes no sence to adjust the  idle mixture screw too at the same time because they influences each other.
6. Start the carburator synchronisation by a fixed setting of the idle mixture screw. ROTAX recomment 1,5 turns out but my experience is try 2 turns out (I have a new carburator).
7. If the mixture is not rich enough (at idle and synchronisation) then it is impossible to adjust the the throttle valve in a rigth way because you have to open the throttle valve to much otherwise the engine stops.
8. In practice there are somtimes differences between the carburator settings, esp. at idle, so ROTAX installed a compensating tube between the intake manifolds.
9. To check the synchronisation of the carburators, the compensating tube (a connection of the both intake manifolds)  is to close/interupt because you want to measure each carburators by itself without being influenced by a connection.
10 Opening the  compensating tube disconnect the intake manifolds and gives you the opportunity to connect your device at every intake hose.
11. For me to close/disconnect the connection between the both carburators (if you have another possibility to get the intake air pressure) by a clamp is theoretical, my experience is the sections of rubber hoses are to short and to stiff to close it perfect.
12. Carburator synchronisation must be performed more often, so I installed a small valve (used for fuel) into the compensating tube, so I can open or close the compensation tube in seconds without any effords.
13. The small valve  into the compensating tube makes sence if you have another possibility to grap the intake air pressure.
14. My new engine have directly after the compensating tube on the intake manifold tube a thread which was closed by a screw. In this i installed a nipple. It was closed secure while the engine is running normal. This nipple is used by synchronisation.

15. The suction of the engine is in high vibration (4 stroke 4 cylinders). So this vibrations have to compensate. If you have simple vacuum pressure gauges you have to do it by your self, maybe your device make it by its own.
16. What you get by mesuring is the average value of this vibrations in the intake manifold. The suction is not a smooth flow, there are complex interrelationships.
17. I dont know how your device works. Ask the manufacturer.
18. If I designed this kind of device i get a vaccuum dose, compensate the measures value, switch this single vacuum dose between the both vacuum connections (automatically in seconds) and show the differences by the led.
19 To take only one vacuum dose it is guaranteed that the value is measured identical between the vacuum connections.

20. Synchonisation is perfect if the manifold pressure is identical at the both carburators (by adjusting the idle adjustment screw). First open the compensation tube. If the manifold pressure and the RMP is unchanged then you are finished.
21. After this pneumatic syncronisation get the engine in normal mode for flying. After flight then adjust the idle mixture screws at both carburators for the right amount of fuel at idle.
22. You can see it at the spark plugs (check the upper spark plugs 2 and 4). Adjust the idle mixture srews so that after a long idle running (long final aproach) the spark plugs are light brown.
23. Ignose the Cylinders 1 and 3 because they are much more sooty. This Idle mixture setting can take multiple test flights because you startet with a rich mixture.
24. If the idle RMP changed significant by this so start again with the syncronisation to perfect the setting (only minor adjustments are needed).  

Ask if the are open questions. Good luck

Benny me old mate - It seems to me that your level of knowledge, about your engine, is severely lacking - my advise, find someone, with good Rotax 9 experience, to assist you (even if you have to pay for the advise). All  the best.