That's right.I was riding a 600 Honda in the north of Thailand some years ago and I could only get petrol with 10% ethanol at one fuel stop.
I got 10% less mileage and the bike seemed,by the seat of the pants dyno, to have about 10% less power.It also ran rough.I filled with straight petrol at the earliest opportunity and things went back to normal.I haven't used it in anything since.
10% ethanol seems 10% worse for everything IMO,and that's not counting the damage to the engines using it.
