I'm new to Banshees, and inherited a '96, stock displacement, aggressive port/polish on the exhaust side, 1.5 oversized carb throats, Toomey T5's, and the standard Toomey airbox vents, as well as an aftermarket timing plate. It's jetted for near sea-level for Florence, Oregon, but I have it in Idaho at about 2200 feet. I put fresh mix in after it sitting for 10 years, and it started first kick and idled beautifully, and ran perfectly. Within 2 weeks, it's loading up BAD in the low/midrange, but screams up on the pipe. Not sure why it changed so quickly over maybe 2 hours' total runtime, but can B12 chemtool additive be added to the fuel itself in a certain amount to clean the carbs safely? I'm not quite yet at a level where I can tear a pair of carbs apart and then have to re-synch them. Half a left turn on each air/fuel screw improved it a bit, but not much. I don't think it's the jetting, because for a while it ran beautifully and never bogged. And then it just started bogging one day.