Horrible bobbing, possible reason

[psolk 3,040]

OK, so for some reason, while I was doing my pre-flight, I changed the CG on the perf init page instead of the takeoff page of the cdu. Well as I was climbing past 290 the plane started to bob horribly. I immediately checked all of my trim settings to see that the perf init page had a CG of 22 instead of 30. I set it back to the default and within seconds the plane settled down. I am wondering if this is what some of the people who say the bobbing is uncontrollable are doing?Just a thought but it settled down right away for me...Happy flights,-Paul

[psolk 3,040]

OK, so I woke up this morning and thought maybe I was crazy last night. ( I probably was but that is irrelevant) I am 2400 miles outside VHHH from KEWR and I decided to try and change the CG from 30 to 22 in the perf init page just to see what happens. Instant bobbing at real time. Switched it back to its default setting of 30 on the perf init page and it settled down.SOOO, as long as I only change the CG in the takeoff page, no bobbing but if I change the value of the CG in the perf init page to anything but the default 30 I am bobbing all over the place.Hoping this helps someone,-Paul