Tend to be more concerned with my carb'd bikes for sure but a splash won't do any harm, all depends how long I think they may be laid up for.
I'm sure I read somewhere that modern fuels are designed to last 6 months or more and are probably still good upto 2 years. In the good old days they could start gumming up stuff within 3 months. A stabiliser or additive to help cleaning when back in use such as redex certainly won't do any harm
Modern fuels are a pain. I have to put Redex in the lawnmower fuel to stop the idle circuitry gumming up in between mows. Winter I have to drain the carb otherwise it is carb off time in spring.
I found this interesting. Note how the fuel/air mix changes after 5 weeks (on page 2).. the change is significant. This is from BP, so am sure we can put a little faith in it. https://www.bp.com/content/dam/bp/c...ices/fuels/opal-factsheet-storagehandling.pdf
It reinforces the benefits of premium fuel. No ethanol in the case of Esso (most locations but not all) and better additives
Modern fuels are a disaster for any length of storage, particularly as mentioned on carb engines, even more so with modern garden/horticultural engines, where emissions for these devices have tightened and jets are becoming smaller and smaller to meet these standards, can gum a jet up in 4 weeks or so without use, run a additive to prevent this with all my outdoor equipment, even through the summer. As above Essos Super Supreme is the only fuel guaranteeing no ethanol in certain parts of England. Use nothing else in the bikes along with Honda stabiliser for over winter storage as it really can withstand long periods keeping fuel stable and not separating.
