Just bumping this very old thread because of a screwup I made recently. I have a new bike, new engine and as I've been doing for a long time, breaking in the engine on Opti-2 @100:1. "Sumpins not right" I told myself after the first few miles. Lots of oil residue from the pipe and not near the power I was expecting. Here's what I found.
I had a gallon of fuel for my snow blower but forgot that I'd already added the oil. So, I added the oil. Now instead of 100:1, I had a 50:1 mix and that was what I dumped into the bike tank. It was nasty. Smoky, stinky and an oil fouled plug.
When I discovered what I'd done I drained what was left in the bike, mixed up a new fresh batch of fuel and Opti, this time at 100:1 and it was like I had a different engine. Power increased noticably. No more oil dripping from the tail pipe and my plug cleaned up beautifully.
Just a word of caution to those who want to run more than the Opti-2 factory recommended 100:1, be prepared for the consequences.
Tom