Aye Welland99,
Any 'Nitrile', rubber, PVC hoses, seals, diaphrams, washers and some brass alloys are also etched by the ethanol in the fuel. The paint/lacquer on the petrol tank, if not a quality ethanol resistant formula, will be pickled by the E5 and E10 fuels. So far as I am aware, only 'Viton' rubber and 'Tygon' plastic fuel lines are resistant to E10 ethanol. I found 1 year old 'Nitrile' fuel lines cracked and perished on both the Ducati and the SRX. The latter's fuel lines are tucked up under the fuel tank above the cylinder head, so any leaks are potentialy catastrophic!
I am also aware that brass jets can be etched if left immersed in E5 or E10 fuels.
So far as I am aware, as long as the octane rating is 95, then Japanese engines should run OK with the fuel, but it is the ancilliary parts and finishes that may suffer from the solvent effects of the ethanol. And, the hygroscopic potential of ethanol doesn't help, if it is left sitting in receptacles open to the atmosphere.
I have been using E5 95 and E10 95 in my Ducati single and add Castrol 'ValveMaster' to the fuel every time I refuel, at a rate of 1ml to 1litre of fuel. I am also using the same fuels in the Yamaha SRX 600ES engine and my wife's Honda Bros 400 and have added Castrol 'ValveMaster' during the autumn and spring periods when the bikes might be used less frequently. When laying the bikes up for more than 4-6 weeks, I drain the fuel tank, fuel lines and the carburettors, leaving them ventilated, so that condensation is less likely to form.
I use the Castrol 'ValveMaster' additive as it doesn't boost the octane of the fuel, but prevents the erosion of potentially 'soft' valve seats (Ducati) and stabilises the fuel to prevent the separation of ethanol into water in the fuel tank, all in the one product. It also has a very economical dosing rate. Most other products of this type only stabilise the fuel, or prevent valve seat erosion.
So, check your fuel lines, possibly use a fuel stabiliser and or drain the fuel system if the bike is not going to be used for more than 4-6 weeks and
ride the bike, because you might no be able to in a few years!
If you have bikes with fibreglass tanks then you are in trouble, I have seen tanks disintergrate overnight, when left with fuel in them at classic bike race meetings. The fuel lines become clogged with glass fibres, as the E5 fuel disolved the resin and turned the whole tank in contact with the E5 fuel to a mushy, porous mess. I believe that there are resins which resist ethanol, but I am not sure if they are durable for any length of time. More modern bikes, with moulded plastic fuel tanks are also being affected by E5 fuels and this will only be exacerbated by the E10 fuels. I know that more modern Triumphs with moulded fuel tanks are having problems as are Ducatis. This following posting was made on the Morini Riders Club GB by a correspondent from the Netherlands, his first machine is a modern Morini and I quote it in full.
Most manufacturers now switched to tanks that resist ethanol, either by material or coating on the inside. Many tanks before 2015 (?) soften when exposed to higher ethanol levels and deform. Usually this results in mounting points not lining up when reassembling the tank. This effect worsens when you have a long project and leave the tank filled with fuel on the shelf not supported on the original mounts...
Seen it both on my 9 1/2 2006 and Ducati GT1000 2006. Have not removed the tank of my Guzzi V7 café classic 2012 lately so that may also have softened by now.
Others may have other advice or more detailed knowledge and if you want to get the screaming abdabs read the Wikipedia entry for ethanol!
Good health, Bill