Am I okay using E10 on a 1981 V50 with Classic Valvemaster Plus? (Or similar product). …Anything to watch out for?
Probably better not to use it. E5 gives a small mpg increase, longer in-tank life, and less chance of petrol additives causing problems, e.g dissolving my tank liner. Your mileage may vary.
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More ethanol in the fuel also gives you more water adsorbtion so steel corossion (tank) and other acids so electrolytic corrosion inside the carb.
e0 is good
e5 is poor
e10 is sh1te
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I said… “Am I okay using E10 on a 1981 V50 with Classic Valvemaster Plus? (Or similar product). …Anything to watch out for?”
“With Classic Valvemaster Plus” …Get that bit?
E10 is obviously not ‘shite’ and If I’d wanted to read comments including stuff like that I’d have looked somewhere else.
The V50 motor is fine with unleaded fuel. Unleaded was already in use in some countries from the early 70’s so most late 70’s motors are designed for it.
I wouldn’t use E10 because its not good for older rubber parts and its easier to use E5 than additives.
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Thanks for that 
, and BobNewBoy
Veefifty sorry for being so abrupt, i thought that these problems with ethanol were well known nowadays…My comments about e10 vehicle fuel arise after 53 years experience looking after old bikes and some years of paid mechanicking (and recently 8 years experience also looking after 4 stroke outboard engines which are regularly unused for a month or more).
To be clear I am not aware that anyone has suggested that ethanol containing fuel affects valve seat wear. that may have been a problem in some 1960s engines that relied on lead in the petrol to lube valve stems and seats
Ethanol is hygroscopic so it absorbs water from the air above the fluid surface. When the temperature of the fuel mass drops there is a ‘phase change’ which causes the water (and some other chemicals) to fall out of the combined liquid and pool underneath it. When the temperature rises again the ethanol will absorb more moisture from the air above it. So the pool of water etc under the fuel will slowly increase. This water will rust steel components like fuel tanks.
I also see clear lines of white & grey crystaline corrosion at the line of fuel/water interface in carburettors which blocks jets and passageways. I have read that this is due to the production of ethanoic acid along this interface but cannot confirm that. This corrosion does not happen with pre ethanol fuel which just tends to form an oily gum when it is 6 month old or more.
In addition as Steve says ethanol will degrade hoses, “o” rings and gaskets not designed for compatibility. All of these problems can be seen to occur after 2-3 months of the ethanol containing fuel sitting in the vehicle.
So (generally speaking) in steel tanked and carburetted vehicles ethanol is “sh1te” that you do not want in your fuel. It is not a problem in vehicles with both fuel injection and fuel tanks that are neither nylon or steel. Because of this serious problem there are loads of different wonder additives to (hopefully) stop these problems. They may work, I am not a fuel chemist and have not tested any of them. In my experience it is safer, cheaper and easier to (1) avoid as much ethanol in your fuel as possible (2) Or if you cannot do not leave your vehicle unused for more than a couple of months with any fuel in the float chambers or tank.
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I never put E10 in any of my bikes unless it is a low fuel emergency - its really bad for steel tanks, carburettors, fuel hoses. Best avoided unless your bike is designed to run on E10, with suitable fuel system components and fuel mapping.
E5 contains a “maximum of 5% ethanol” which means it may contain none, some E5 such as Esso Synergy 99 are likely to contain none.
On my old guzzis I still add a dash of lead substitute every few tank fulls.
Russell
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I can’t find anything about the performance of the fuel stabiliser you mention, however the Project Farm guy did do a test on some well known fuel stabilisers which was not very positive but one of them worked a bit - see first 21 min of his ProjectFarm fuel stabilisersvideo
If a newbie can add his experience? I never had any problems with E10 in my Cali1100ie over about 60,000 miles - no valve seat recession, no fuel line rot, no carb internal problems, non of the normal ‘it’ll blow the world up!’ possibilities. I burnt an exhaust valve out but I think that might have been me. However, I also have to add that the 1100ie was doing a minimum of 50 miles a day on my work commute, so the E10 didn’t hang around in the tank between fill ups for long.
My two K100s - now that’s a different kettle of fish. If I don’t feed them E5, E10 really does turn the rubber parts into goo. Known and documented problem there.
[Edit] I missed the relevant part of my response. Before I sold it, I also ran my second V50II for just short of 12,000 miles on E10 with no E10 related problems at all.
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Can we please all keep the language within the forum guidelines, if you do not like E10 fuel there are many words available in the English language to describe it without resorting to mild swearing.
Please remember that this is a public forum and not a chat in the pub with your mates.
I trust you will take note. Thank you Chris
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E10 petrol was only introduced in 2021 and has caused problems for classic bike owners. One big problem is it goes off, sometimes just a few months old, smells funny and just does not burn properly. I do not leave the stuff in the tanks of bikes or chainsaws etc.
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I agree. I should, perhaps, have commented that I’m a relatively high mileage user (20K - 26K miles a year) because I’m one of that increasingly rare breed that only owns motorcycles and no car. Consequently it didn’t take long to rack up those miles on E10. Also I’ve corrected my initial post - it wasn’t the V1000G5 but the Cali 1100ie.
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What we’ve found in the workshop is tgat, despite things like float needles being tipped with viton rubber (ethanol resistant) it’s maybe more about the co-solvents in modern petrol. We’ve found very eroded tips on needles of 1980/90s bikes with persistent flooding problems, Japanese and European. On examination several (many) carbs are compromised with observable grooving around the float valve seat, as well as debris from degraded fuel lines.
We fit diesel fuel lines as a default, as there’s been ethanol in diesel (anti-waxing agent) for decades. Also a good inline fuel filter is never a bad idea.
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@royston one thing, albeit expensive, is to fill with Aspen fuel before any lengthy layup. It is 100% ethanol free. So doesn’t get the rusty tank problems down the line. There used to be an option with Shell V Power or Tesco Momentum E5, which had to be sold as E5 but was in fact 0 ethanol and 99 Octane, however with the mess of things currently that needs qualifying.
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I would not use E10 unless I absolutely had to. I’d stay away from it even if you are using fuel additives. I know of at least 5 local bikers who have had serious problems with carburation due to E10.
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