You know, it's a funny thing. The bike just might have been having a bad day yesterday. It was about 70 degrees today and I took it out again with the 84 jet and it didn't four stroke.
It was four stroking all day yesterday and it was driving me nuts. I was getting worried that I might have some other problem like a timing issue or something. A ride later in the evening eliminated all of the high speed problems I was having though, so it would seem I was too rich.
I haven't pulled the plug to check things out yet, but I rode for a good 10 miles today at some pretty high speeds with no obvious ill effect.
I a running a high flow filter, it's the metal mesh one with the rubber coupler that treats and 1977mopeds sell.