I think this is now the same issue I have with my 1993 SL 750. If I watch the carb openings while I rev it up (past about 1/2 throttle), it looks like it is spraying way too much fuel and it bogs down - it simply seems to have no top-end power. Mine doesn't die, though. (This was after adding Seafoam to the gas, and spraying Seafoam into the carbs while it was idling, until it was choked to death - waited about 10 minutes, started it back up, endured all the additional smoke for a few minutes, and repeated - no change in how it was running - well, maybe it idled a little smoother.)
Is it possible that dirt in the carburator(s) is causing it to spray too much fuel? Or am I looking in the wrong place? (Like maybe not having strong enough spark to handle the additional fuel?)
I don't want to start throwing parts at it with no real clue as to what the issue is.
I wish an expert would weigh in with some suggestions/advice.
Moose