It really depends on how you ride. If you are MX racing hard with non-synthetic, go with a mixture in the 40:1 range. I ride trails, sometimes hard, and run full-synthetic Motorex and use 50:1. The manual says I can run up to 60:1 for trail riding. With modern Synthetics 32:1 is old news.
For the mixture vs power debate. I would think since less oil = more gas, and more gas = more power, then less oil = more power. This may just be made up for in the required re-jetting though.
You,ve got that backwards, more oil= less fuel= more air ie leaner mixture= more power
less oil= more fuel= less air ie richer mixture= less power
The difference is tiny though. What i think alot of you are forgetting though is that the oil comes out of suspension and pools in your crankcase. Richer fuel oil mix = more oil being spread around your motor. I'd personally never run 50:1 or higher.
I run 30:1 and would go even richer if i could afford the oil.
What you are saying isn't making sense to me.
1) Changing the oil/fuel ratio has nothing to do with the amount of air going into your engine. But reducing the oil does mean more fuel, so yes a richer setting. Then compensate with jetting and the result is more air AND fuel at the same mixture, due to slightly less oil. Will the change from 30:1 to 40:1 be noticeable? Doubt it. Maybe to some pros.
2) I don't see how the oil in my suspension is going to get into my crankcase and pool...
3) The "32:1" was made years and years ago when oil quality was much worse than now. Many people run 60:1 in KTM 2-strokes and get well over 200 hours on a top end. Yes, this is off-road. But I would not hesitate to do 40:1 for MX and save a little $, have less spooge, and that tad better response and power.
I'll start by saying spooge and throttle response has zero to do with your oil fuel mix and everything to do with your air fuel ratio ie your jetting.
As far as the more or less oil goes, you're talking yourself round in circles now. Your motor sucks in a set volume each stroke, if you take fuel from that volume by adding oil then the result is a leaner condition as the oil isn't combustible. the reverse is the same, if you add fuel to the total volume by removing oil then a richer condition is the result. You're right though it wouldn't be noticable power wise between 30:1 and 40:1 i doubt would even show a difference on a dyno. Where i believe you do gain power from extra oil is better ring seal and less friction and heat. Then there are benefits of extended service life.
You missed some stuff and read my post wrong.
1) Oil mixture DOES affect spooge. Think about it, if you had no oil, there would be no spooge, even with a rich mixture. Because it is the OIL that causes spooge. Less oil will have less spooge. Jetting likely has a much bigger effect than a small change in oil ratio, but oil ratio affects it. Since the oil isn't creating your power, it is essentially blocking the combustion process, remove some and response may increase.
2) Read my post again, I mention jetting at the same time as changing mixture. Basically, to picture it more easily, you have an air/fuel mixture and an oil percentage. Lower the oil and your air/fuel goes up. More air/fuel means more power.
3) If there is so much oil it is becoming spooge or pooling,then it is not helping with ring seal and friction.
How the oil mixture ratio creates a friction vs cumbustion plot would be interesting. What ratio creates the best power? That would have to be experimentally tested.
For me, I'll save the money and have fine reliability at 50:1.
