Diesel, yes the caltex near the IGA. I have used E10 a lot in the car and ST11 with no obvious problems. The caltex now only sells E10, 95 and 98 (and diesel). For the car it is a good solution as it has been optimised to take advantage of the higher octane (94 plus) so I use it instead of 95, but goes even better on the 98 (but not 14 cpl better!) I have probably used E10 in the car for about 140,000kms out of the 156,000kms it has on it. The bike probably 60,000kms out of the 90,000kms I have only put on it myself (total of 156,000kms).
If not rated for the use of E10 it can cause problems with rubber components that may not be up to the ethanol, so that may include valve stem seals and things like hoses and carb parts. I looked into my carbs recently and all the rubber parts looked as good and flexible as new. I know that various Kawasakis cannot use more than E5 for warranty purposes (E5 is the European level of ethanol). I doubt whether rings etc would be adversely affected unless the use of E10 leaned out the tuning too much in carb engines.
I have seem pictures and reports that supposedly show a lot more crud buildup in engines, and some have blamed ethanol for failures in ST11 carb diaphrams, but I suspect a lot of that is from the US where the standards seem lax, petrol quality very suspect in places (petrol additives have to be designed for ethanol use) and E10 turning out to be E40! Australia should not have those problems. Many long term users of E10, because it has been mandated for many years in some parts of the US, don't report problems, but others get problems as soon as they go through some states. As many bike manufacturers say no ethanol at all, I don't know how warranty would work in states with mandated levels of the stuff. E10 can have issues if not stored properly and petrol station tanks not clean and water removed. If in doubt I go for whatever seems to be the highest volume seller.
Oh yes, E10 is not that great for the environment all things considered.
