Carbs on the k3 can be tricky on an underused bike, but on a daily rider or tourer the better fuel economy they deliver can be worthwhile. I know I was glad of it touring Scotland on my first big bike, a cb550k3. Went across from Fort William to the east coast, then back down past Edigborough and didn't seem to see fuel stations for miles, ( pre sat nav days) when we finally found a filling station my mate was on reserve on his cb250 and had used up my spare gallon can too, my bike wasn't on reserve yet. Strangely on the Mid and North Wales roads our bikes used about the same amount of fuel - every film up matched to the penny but on motorways and long open bits of road the 550 basically didn't seem to burn any fuel. Same story poping down to Hereford which I used to do a lot - the cb550 sipped fuel in a frugal manner. My cb500 wasn't quite as economical and after 7pm the whole 80 miles had no fuel stops open and 20 miles from home to re fuel, the k3 was ok with this, the 500 needed to re fuel in Hereford or you'd be pushing it the last 15 miles after 7pm where the k3 was just about ok to do the round trip on a tankfull.