Deverix,
I don’t know if I am an expert or not. Some people think I am just an opinionated old f _ _ t.
I have never used Sea Foam. I am not a fan of carb cleaners and fuel stabilizers. Using carb/fuel system cleaners is not a substitute for a clean fuel system. If grit gets in the system, it will stay in the system even after the use of carb cleaners. It seems that most of the time when cleaners have been used, the problem was not solved and the carbs had to be cleaned by a mechanic anyway. I have had to change carburetor slides on bikes that used fuel stabilizers/preservatives because the rubber diaphram had become hardened, not soft and pliable. Even though the diaphram is not in direct contact with the liquid fuel, it is exposed to the vapors.
Most brand name fuels have sufficient cleaners as they come out of the pump. I use premium unless it is not available. Then I use mid-grade.
Make sure the fuel system has been flushed and cleaned (tank, fuel lines, and carb). Fuel tanks can be drained, removed from the bike, dissassembled and flushed with water using a garden nozzle. I usually catch the water coming out in a white plastic bucket. That way I can see what kind of junk the tank has collected. When stuff is no longer showing up on the bottom of the bucket, the job is done. Shake out as much water as possible and leave the tank in the sun for however long it takes to make sure it is completely dry inside. Use an in-line fuel filter. Buy brand name fuels and avoid gasohol if it is possible in your area. In my area everthing has alcohol. If you fill your bike out of a gas can, make sure the inside of the can is clean.
If the rest of the fuel system is contaminated with sand, rust, etc. and not cleaned, cleaning the carbs is not going to last long.
If you do not feel comfortable doing this yourself, it may cost a few dollars having a shop do it, but done properly, the results are worth it. If you do this yourself, take the necessary precautions for working with gasoline and gasoline fumes.