There’s also the fact that E10 & E5 fuels don’t contain 10% & 5% ethanol .

I have watched a guy on YouTube testing are fuels and he found E5 was between ethanol free to 2.5% .
E10 was between 2.5 to 7.5% so it all depends on the brand and blend of fuel used

Good point DTO. It's only "up to 5%" or "up to 10%". Although it's worth noting that all petrol, except the very high octane rated fuels (such as Tesco 99 octane momentum or Shells very high octane stuff) come from the same factory refinery/s, and is in a raw form (with the ethernol already added) when taken to the delivery stations ready for distribution to garages. When ordered, fuel is allocated to a particular garage brand and the additive packs relevant to whoever has ordered it are added to the fuel and it then becomes Shell or BP or whoever. The ethernol is added at the refinery stage so most fuel of any brand should be coming through with almost the same ethernol levels. The main variance on this will be from month to month as ethernol is either more available or less available so might be 8% one month then more the next, less the next month etc etc. The amount of ethernol in the fuel may also change slightly in the storage tanks at garages as some of the ethernol in the fuel is collected by water at the bottom of the tanks, but this is very slight.

I think the video above is not bad but he only leaves the fuel and water standing for a few minutes. It really takes a bit longer for the full effect to take place so he may not have collected all the ethernol. In addition, did he fully shake up the petrol properly before he added it to the test tubes. This can also affect how much ethernol was in the actual fuel he tested. The fact is was so clear indicates he may not have done so.

I dont have enough time left on this earth to worry about such infinitesimal data, I leave it to others to WORRY about such small things!

Jim

Actually, me too Jim!

Been out today and filled up. I brim the tank, literally full. This tank has achieved 83 mpg. That’s c9 or 10 miles per gallon less than before e10. I realise it’s cooler now but I only ride for pleasure now. I will only go out if I can get a decent ride in, I’ve only been out 2 time on the last fill up, just over 100 miles so I cannot blame lots of clod weather warm ups. I don’t warm the engine up by idling it, I start it, wait a few seconds for the oil to circulate then proceed. I don’t start the engine to ‘top the battery up’ either. My journeys are very similar, I stick to A and B roads and keep to speed limits. I am now more convinced I’m getting less mileage with e10. I will try a tank of super unleaded to compare the next time I fill up.

Interesting smeg. I've just checked mine today having filled her up to the brim. With this warmer weather my fuel economy has shot up to 90.34mpg. Mixed riding but quite fast road work in the main. But...she has had some E5 97octane in her as well since I couldn't get E10 95 octane when out in the darkest parts of Suffolk the other day. Only about 3ltrs though in a full tank of mostly E10. My tank holds 9.5 ltrs.

Is your bike due a service bro? Seems you have dropped a bit more economy than I would expect. E10 doesn't normally make very much difference to mpg. Is the oil overfull? That will drag it down?

I went for a ride yesterday along my normal Sunday pleasure ride route, on a Saturday, as there as not much traffic. I achieved 91 mpg from a full tank of fuel on my NC750x for the journey, riding a similarly as I could, as I did pre-September and on 95... this is on the top end of what I was achieving on 95. I can only conclude I see no difference.

That's brilliant Peter. The NC is certainly good on fuel economy. But it's also down to your riding skill.

Data wrote: Sat Jan 01, 2022 8:00 pm Interesting smeg. I've just checked mine today having filled her up to the brim. With this warmer weather my fuel economy has shot up to 90.34mpg. Mixed riding but quite fast road work in the main. But...she has had some E5 97octane in her as well since I couldn't get E10 95 octane when out in the darkest parts of Suffolk the other day. Only about 3ltrs though in a full tank of mostly E10. My tank holds 9.5 ltrs.

Is your bike due a service bro? Seems you have dropped a bit more economy than I would expect. E10 doesn't normally make very much difference to mpg. Is the oil overfull? That will drag it down?

No Data, it’s not due a service and oil was only checked yesterday, it’s spot on. I have eaten my body weight in mince pies though, would that affect it?

Arrr...the mince pie factor! This changes everything. I too have experienced this factor. I believe it does have repercussions for fuel economy. Also Christmas pudding seems to cause this problem! Not sure what the answer is just now...but experience tells me it's complicated bro! When I've eaten some more of both these things I may have the answer, but for now just keep eating!