Ariel Owners Motorcycle Club

Dear fellow enthusiasts,

I hope riding season is to a good start. We are still waiting for some warm weather here in Minnesota. I am curious about shelf life of petrol left in motorcycle tanks. It is common wisdom that petrol left in tanks is going to lose volatile components. I am curious if any of you has an experience, where fresh petrol made a difference in starting or riding motorcycle.

Here in Ontario, I find gas left in the tank or in my gas cans over the winter months holds up pretty good.
all my bikes fire up usually 1st kick heck even my 83 BMW R80 runs good on old winter gas.
I have yet to have any gas go bad where it won't fire . Maybe in the new bikes it may make a difference ?

hi petrol starts to go stale when it gets air and water in it when it is in a metal tank and with E10 in it goes off quicker

I have never had any issue with petrol left sat in a bike over winter, or even longer. I'd think if its left open to the air for a long long time then the volatiles will evaporate and you will need to do some cleaning out, but for a period of months, or even a couple of years - no problems. I always put the `stale petrol' thing down to either myth (by folks with time on their hands...), or people with more modern bikes and higher compression ratios than my Ariels (and other marques) have.

Important is to empty the floatchamber before leaving the bike for a while. In these small compartment the volatile components disappears much quicker than in a big pertol tank. Good is to leave the tank nearly full.
It is tested that for longer storage E10 is better than petrol with lower methanol percentage. Methanol absorbs more water which comes from humidity and this prevents the tanks from rusting. But only up to the pint the pertol is saturated.

Markus

The chemical bits that help the engine get started disappear over time (the petrol sold during the cold season(s) has more of the volatile aromatics in it than the stuff sold in the warmer months) so I'd expect 'old' petrol to have more potential for causing problems than something fresh from the pump.
I've never had a problem myself with fuel that's been in the tank for a lot of months (rather than years) but only recently a friend had a problem with a bike that wouldn't start until he tried putting in new fuel, which seemed to magically fix everything.
(But maybe he had old summer-grade fuel and the weather was still too cold!)
Petrol with more ethanol definitely sucks up more water vapour; my Triumph has a plastic (nylon) tank and these are renowned for deforming and 'growing' as a result of taking up water that gets absorbed into E5 (and higher) petrol. Doesn't happen if you use the bike a lot (the fuel is changed frequently), only when you lay it up for a while and worse if the tank is part full. This issue should be well-known to our North American friends as they've had high-ethanol fuel for much longer than we've had to suffer it 'over here'!

SG

Not strictly on topic but I started my motorcycle last week after a winter layoff and BOTH petrol pipes to the two carbs are split and leaking fuel. The rubber reinforced tubing labelled "suitable for unleaded fuel" was installed by me a year ago. The tube had perished completely and fell apart in my hand! I have never had this before and I can only assume that this is down to the higher ethanol content of E10 fuel. I had not drained the carbs over winter. Be warned.
Dennis

hi i have had a lot of problems with rubber pipes leaking on motorcycles and cars etc with E5 and E10 and old motorcycle petrol tanks leaking with the bottom of the tank rusting out

fuel with ethanol in does absorb water and does go off after a few months, it also attacks a lot of plastic and rubbers and the higher the ethanol the worse it gets, it can also attack brass and if left in a carb it will block up the passage ways with a sort of gum, modern fuel injected bikes are less affected , had a small generator that i bought cheap that did not go, and the carb was gummed up and even with an ultra sonic cleaner it would not work and had to replace it, now it works just fine. now i use aspen Swedish fuel in it which is more expensive but stays good for up to 5 years and i know some people who use it in their old bikes which only come out on high days and holidays so dont get a lot of use and they are fine, no problems they just work.
Had to buy a new fuel tank for my fieldmaster as it sprung a leak and was going to cost a small fortune to repair and repaint it, so i bought one from India which looks right but the bolt holes did not quite line up so had to do a bit of a mod to fix that, but it does seem to be holding fuel ok.

I left some on the shelf once,, only lasted 10 minutes and took the paint off