if you don't have elec ignition GET IT!! the carbs must be balanced nearly perfect, then you shal never have to touch them again (contrary to popular belif) my fully rebuild 18R-G rebuilt and balanced carbs, elec ignition, iridium plugs, all i do is change the oil and filter!!! i've had it like that for about 18mts now!! and the elec ignition helped that flat spot.. but i can still notice a tiny bit if it's in like 4th on flat road (or a dyno) it will kinda choke.....verooommm!! i think it is kinda the nature of the carbs..