A couple of years ago in Germany a truck driver advised me not to use E10 stating it messes up the carb diaphragm
More scaremongering
a carb diaphram doesn't directly come into contact with fuel and if true the car/bike was more than likely non compatible.
If it was a bad as certain people would have you believe, it would be out there by now. Cars/bikes would be stopping in the countries around the world where it's been in use for some time (France & Belgium in Europe) some upto 10 years in places. I've seen no such reports has anyone else? The real issue is hoses/seals and some lower spec alloy in the fuel system, that aren't resistant to higher levels of ethanol. They start to degrade/leak rather than engine problems, non compatible cars/bike will still run on E10, albeit at the expense of the fuel system components if it's left in there.
Obviously those cars/bikes which can't use E10 will have to use E5 or 98ron which will still be on sale. What is interesting is apparently once a garage has switched to E10 by 1 Sept 21, they can't sell E5 or so I've just read here
https://www.autoexpress.co.uk/news/104126/e10-petrol-explained-uk-prices-checker-tool-and-it-ok-your-car Last sub paragraph in E10 petrol v E5 petrol paragraph, this is I believe is due to when E5 is offered alongside E10, most opt for E5. If this ends up being the case, which I'd say is very likely, there will be E5 or super garages selling diesel and E5 I guess. I will be a bit like hunting out LPG and electric charge points
The saving grace is bikes appear to be well ahead of the game, in that most Jap manufactures bikes post early 2000s being compatible and some like Yamaha anything post 1990!
This is a good read and mostly bike related
https://www.bennetts.co.uk/bikesocial/news-and-views/news/2020/march/what-is-e10-fuel-and-is-it-safe They other big question is fuel degradation, in this case the hygroscopic effect extra ethanol has. I would point out the fuel has to be open to the atmosphere to allow this to happen, same applies to brake fluid although at different rates. We've all seen the warnings don't use brake fluid from an opened can/bottle, well yes to a point, if the can/bottle is correctly sealed it can't absorb water. I test all my fluid everytime I use it new and open and it's fine for years, trick is open the can/bottle take out what you need and reseal it straight away. Nice little earner for the brake fluid manufacturers
Presumably the same will apply to E10, but the question is how long, again it's been used in other countries for years not seen anything ringing alarm bells for bike stored over winter as yet.
Lastly drop in performance again unless your bike is either highly tuned or running very high compression as standard (some are) or you've done serious engine work. Any loss of power will be minimal and not noticeable in real world riding.
I guess we'll find out soon enough, with a little over a week to go before E10 must be sold on the forecourt. I won't be bracing myself for a glut of non running bikes turning up all of a sudden.