You might find that the engine will not accelerate or increase RPM.
This is often caused by torn or improperly seated carb slide diaphragms. On a V4, the carbs open with intake vacuum and when one or more of the diaphragms are torn the slide will not lift. In effect, this would be like not opening the throttle on that carb.

You would need to inspect the slides for tears or make sure they are properly seated. A quick way to do this is to check for vacuum resistance by manually lifting the slide with your finger. If the slide moves up easily without resistance then rapidly returns, you should remove the top and slide to carefully inspect the diaphragm rubber and seating in the carb body.

You can also compare the carb pairs by lifting the front two together, and the rear two together. Due to different slide spring lengths and pressure, the test is more accurate with front and rear pairs.