After heading off in multiple directions to solve this I decided to replace the float bowl remote jet o-ring for the 4th time.   Instant success... I thought is was the problem initially and replaced it with what was supposed to be the correct O-ring a couple times.   After re-ordering from a yamaha parts house I decided to check the rings with a digital micrometer....  although almost visually the same the cross section diameter was a bit short.   I would not be surprised if others have fought this same issue.   However it did give me the opportunity to try a couple carbs ...both with the incorrect new "o-ring" giving the same result... but I have it timed and the worlds cleanest exhaust pipe.   Presoaked with simple green... big mistake... smells even after decarburizing with the torch.   Need to be careful with the torch method-   A buddy helped me do this to my old IT465 silencer which must have weighted 15 lbs....  heated it up cheery red and said.... turn off the gas and we'll just poor the oxygen to it....a minute later the entire molten guts flowed out the end of the pipe....needed a lighter silencer anyhow.