Quote Originally Posted by jm21ddd15 View Post
A point to think about, fuel is not the same, at each location. 87 octane in one station is not exactly the same as other stations. Different companies use different additives, and the length of time the fuel has "sat" in the gas stations large tanks, has an effect on it's performance. Fresh 87 octane, does not "stay" at 87 forever. it loses some of its "strength", as time goes on. Plus, you don't allways get what you think your purchasing, when buying fuel. I have a fuel tester, that will separate and tell the percentage of alcohol in the fuel. I have several times, seen fuel pumps marked at 10% alcohol or less, but when the fuel is tested, it's close to the 18% range. High alcohol is bad for small motors, like chains saws, and will decrease your milage on your cycle or car. This is another reason that some riders claim they get different MPG than others.
It could have been a bad tank of fuel, but the bike had pinged several times earlier, just not as badly as that one time. I rode it for over 40,000 miles and it definitely required higher octane fuel than my 2016, which has never once exhibited a hint of detonation. Maybe it's those louder pipes on the 2016 covering it up!

I've seen this before. I have a '98 Valkyrie Tourer I bought new that runs fine on the 85 octane fuel they call 'regular' here at high altitudes. But I have a '99 Valkyrie Interstate that knocks badly on anything but premium when the weather is very hot. The Interstates had an ICM with a faster advance curve to compensate for the extra weight, so that could be a factor. Since I bought it used it's possible the P.O. installed a trigger wheel. Interestingly, the Interstate also gets considerably better fuel mileage than the lighter Tourer. But there's definitely a distinct difference between the two bikes, even though they use virtually the same engine.