what fuel do you use for your sportster and why?
i have a 2015 iron and i've always used 98 premium
but the other day a harley mechanic said to me to use 91 because it runs better on it, in america its all they have.
that doesnt make any sense to me. i understand maybe its made not to run so lean so i tried 95 and didnt notice that much of a difference.
They measure octane rating differently in America. 91 AKI is not 91 RON, in fact it's not even directly comparable, depending on the mix of chemicals in your fuel, 95RON could be 91MON, or 85MON, and AKI is the average of the MON and RON reading. Singapore/NZ 98 (which I presume would be similar to Australian, but don't know) is 93-94AKI, which means 95 would be under 91AKI, and 91 Australian is pretty much flamable dishwater. Americans also fill all their fuel with that dirty ethanol crap, but I wouldn't put it in my Harley.
Short answer: your mechanic doesn't know diddly squat about fuel octane.
Not sure if this answers your question but it's the viscosity of the oil. My understanding, using 15w40 as the example, is that 15 is the viscosity of the oil when at a colder temperature (I believe the W stands for winter) and 40 is the viscosity when hot.
Gets confusing when you start comparing engine and gear oils because 20w50 engine oil is the approximate equivalent of 75w90 gear oil and can sometimes be interchangeable.
Just on 40 years riding Harleys, started out on Super with lead, then they went unleaded still stayed with Super as my valve seats loved it! but was a dirty burning fuel. now since i've looked in my motor that has run BP 98 and if can't get that i put some VP with 95, but after seeing how clean the BP 98 burns i'll stay with it!
and i buy it from top of the hill like Wimbo ( but a different hill)
