Octane Value for UK United Kingdom Riders

Paul Sutton

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Is the Unleaded 95 RON the correct fuel for us to use in the UK?

I suspect the Octane Value of Unleaded 95 is slightly higher than what is recommended in the old user manuals.
My US user manual says to use Regular Gasoline which I think was 87 in the US. In the UK we use RON method for octane rating which is approximately 4-5 units higher than the equivalent old US petrol (US 87 = 91 to 92 RON). By retarding my timing slightly the bike seems to run worse whereas the factory setting seems better which I would expect if the Octane value is slightly higher.

Any experience as to what petrol runs best in the UK??

Thank you.
 
On the inside of my 81 side cover it has some specs, it calls for 91 octane on the RON way of measuring.
Here in the states most 91 rated fuel is alcohol free, but most are in pumps along with alcohol fuels, so you will get some alcohol fuel mixed in with your alcohol free fuel.
Seems odd that if leave out the alcohol the fuel cost goes up. By about $.15 per gallon.
Any way I run the highest octane they have usually 93 octane. When first got the 75 running I just put about a gallon of regular fuel in the tank and it ran but under hard acceleration it knocked and pinged real bad. Once I ran that down to reserve I filled it up with Sunoco's 93 and all the knocking went away.
I would recommend at least the 91 you have or higher. This might help prevent holed pistons.
Leo
 
Seems odd that if leave out the alcohol the fuel cost goes up. By about $.15 per gallon.
I'd hazard a guess that it's probably because alcohol is cheaper than gas... adding alcohol is a bit like watering down beer, you get less gas and beer by weight.

The tank I took off my bike is still half full of 30 odd year old four star lol. I wonder what it would run like.
 
It will run fine on standard 95 unleaded, you would barely notice a difference with super unleaded which varies between 97 and 99 ron.
Not sure how it will run with the 30 year old fuel though.
 
Thank you for all replies. I must try the Super to see how things are. Maybe the engine will be smoother, or perhaps the plugs will get more carbon deposited on them???
 
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