After seeing a couple of pics of these new Triumph vertical twins with carbon buildup on the valves, I've taken the precaution of adding a bottle of carb/injector cleaner to my gas every 5,000 miles. One bottle is good for 20 gallons of gas, so I just pour a little in before filling up. I don't want my valves looking like this:
I might be just paranoid, and I don't know if it's doing any good. Oh, and I also use a good brand of gas(usually Chevron) and stay away from the Circle K type pumps.
