Re: 100:1 Mix
I know less about engines than you guys, but my understanding is that some engines also have different requirements. I have a couple of old Villiars 2 strokes from somewhere between the 1930's to 1950's and also a model 1932 Sachs 2 stroke made in 1934. Well made engines. The old guy who sold the engines does restoration of old Cushmans, Whizzers and such and has an international reputation for his knowledge. Anyway he was adamant about not using either synthetics or opti 2 in the vintage engines. He said to use what they were designed for which was 30 weight motor oil at 16-1. His recommendation for best results was for Shell aircraft engine motor oil (Aeroshell) in 30 weight. He said this is what all of the guys racing small outboards used back when if they wanted to keep their engines from blowing up. Found some, but very expensive. I use that oil just for those old engines. Any other of my 2 stroke stuff gets opti-2. Anyway, he said the engines then were designed differently. Maybe he's all wrong and old school, but he knows more than I do. These old engines have a reputation of running forever, so that's what I'm counting on.
Regarding the opti 2 and longevity, I don't know and I don't race bikes, running them hard. However, when you cut up ten logger cords of firewood going at it full throttle all day long under heavy load, day after day after day, it has to be something like racing a bike engine at the max. My old Jonsered 621 keeps on cutting with lots of power and virtually no smoke. Tool rental places use it and they must have a reason. My suspicion is that we have a number of good options for keeping our engines well lubricated. I think its good to be both curious and cautious and then use your best judgement. Gentlemen, start your engines... vroom!
Someday when I grow up I will probably lose interest in toys with wheels, but until then...