there's two kind of bogs ive come across, the carb/spark bog and clutch bog.
does the buggy do the same thing in nuetral or just drive. what i mean by clutch bog is that when the buggy is in gear a clutch arm can break and continuously grab the bell when it shouldnt. some symptoms could be walking away at idle or idles find, kind of sluggish but when you brake from driving it cuts the motor out. not sure if thats the case but if nothing else works might be worth checking.
the other....
obviously the carb is not the problem , youve cleaned one and replaced it. a vacuum leak might cause this, but the main symptom of a vac leak would be erratic idle, up and down not smooth. where to check, 1. the vac lines, both the carb and fuel pump/petcock are vacuum actuated so it will efect both which is the whole fuel system. another place it could be leaking is the composite spacer under the intake....they will crack over time, or for no reason at all. if youve been through all of this and it looks good, the CDI might have just decided to take a dump.
thats a few things to check, let us know.