What fuel do you choose for 50 year old engine technology

Ethanol is hi octane, they reduce the octane of the remaing petrol the more they add to retain the octane. Pure ethanol is 109 octane. But ethanol has lots of other issues, enough to use ethanol free if you can get it.
Easy to remove ethanol from gas, just takes water (and a bucket and siphon, ideally). I and other have posted on this forum, or do a Google search - there are youtube.com videos as well.
 
I use pump premium and as long as it is fairly fresh the bike runs fine with it. I have roadster tank, go out for 90 - 160 miles and I am NOT going to carry gas!
 
Curious about use of premium in an 8.5-8.9:1 compression engine (unless you have a Combat or modified engine?) Tx
 
Higher octane gasoline is more difficult to ignite therefore less detonation. Use any gasoline as long
as detonation does not occur regularly when ignition timing is set correctly and air fuel mixture is good. Continual detonation will destroy the engine. Graham
 
Just topped up for our 350 Kms. up to Penetanguishene n' back cottage invite with Shell cheapest / expensive nowadays fuel . In went the debit card . Wait . P.I.N. , Pull . In went the CAA Plus card . Wait and pull . Choose one of 3 options ( cheapest ) . Lift pump handle and fill . Rock and roll in the morning with wife , booze , food , fishin ' gear and worms on ice . Life's good .
Monitoulin Island in 2 wks .
 
My Commando still isn't finsihed but I can say that my T140 (8.6:1 pistons, head never been skimmed) runs perfectly on E5. If I can only get E10 it'll run OK as long as I'm easy on the throttle at lower revs. Hard throttle opening at anything below about 3500 can make it pink - no such trouble with E5. Another observation, for what it's worth: E10 two stroke mix (50:1) seems to last forever in chainsaws. I've started saws that have sat for 2 years with half a tank and they've run fine. I sometimes put 50:1 two stroke mix in the Triumph if I need to and it seems to like it despite it being E10 fuel.
 
Ethanol carries less energy per cc or oz, so the greater the % the richer your carb needs to be. On my Digger with Honda engine with E10 it needs a bigger main jet, was fine with E0 and with E5 needed warming up a bit before full loads could be used.
 
I found this video to be a plausible and understandable explanation of ethanol blending and other science behind pump gas.

 
Higher octane fuel is slower to ignite than lower octane, thus it resists preignition, detonation, spark knock, or what ever else you care to call it. Slower to burn not slower burning. Semantics vs engineering. Google articles written by Gordon Jennings, published in Cycle World, on detonation and efforts to control it in aircraft engines going back to the early 1930s. Interesting reading.
 
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