Common question I know, plus we are far from that put your bikes away for the bad weather stage. I just have lots of de conflicting answers. Situation is I could be working abroad for months on end, the honda storage guidelines are too much hassle (take fuel take off empty and spray rust inhibiting spray inside). I prefer the brim it with fresh fuel and jobs a good un. Surely modern fuel doesn't go off that quick (It's made from oil for Christ's sake, it has been in the ground for millions of years). Any clarity thanks (Arthurbikemad what's your thoughts?).
It does go stale but a few months will be fine, would go off quicker in a jerry can etc but in the tank it will be fine
If you are going to leave it for months and months, change the oil/filter, this gets as many contaminants out as possible. Add a fuel stabiliser to the tank and top up with fuel and run it for a few mins. A full tank of fuel stops any condensation forming in the tank and the stabiliser will prevent the fuel going gummy and coating your engine in varnish. Allow air to circulate around teh bike to stop things going mouldy, and if poss get the tyres off the ground by putting the bike on paddock stands.
+1 to what has already been said. I've done the same over the past 2 winters as Kentblade described and have had no problem with fuel.
I've had had to leave bike standing in the past for 6 months when working away at her majesty's pleasure and just brimmed the tank so it doesn't rust, never had a problem
I have always filled my tank up to the brim and left it. sometimes from Oct to March without a single issue ever. So I personally would not worry about it
A lot of the stories about with fuel goin off is from the US, yes our fuel does go stale but it takes a lot longer to do so in the UK due to us refining it more and adding more additives than those over the pond. Our fuel will easily stand up to 6 months and more without adding anything else to it. Has anyone actually tried to find a bottle of fuel stabiliser in the UK like seafoam? We just don't seem to need it, lack of popularity means no one here sells it bar specialty import shops. Why is this topic not a big thing on car forums and their service manuals??? Same principals apply there.
I have never had any problems, I leave motocross bikes months without problems, just run the card dry. only when it evaporates in the float bowls of carbs... then you get a claggy mess, and its a bu**er to clean the carb. I'm no chemist but if its not evaporating I recon your okay. Mike.
All the main sellers (shell etc) say the shelf life is 12 months or more if stored in a cool dark place, I have had bikes parked for 18 months with no prob, as said also take into account all the other apps for petrol and the lack of care thats taken with fuel storage, for example:- Plant equipment we have around me here often sits for 8-24 months and always starts fine, as do many mowers and generators etc. I do use a product call TruBlu fuel stabiliser in some apps like mowers but tbh have never had a problem without it.