no but not mixing fuel to oil ratio correctly will seize a motor
No, all later model Harleys run on low octane fuel.
Fuel for gasoline engines which posesses a low octane rating using the R+M/2 method.
100 octane. This is why aviation fuel (avgas) is typically called 100LL, which stands for 100 octane, low lead.
Low octane fuel.
Low octane fuel, timing to far advanced, overheating.
yes, it is low octane unleaded and $9.00 a gallon
93 octane gasoline if it is not a diesel other wise it is a low sulfur diesel.
yes you can. the higher the octane "within reason" the less chance of you having spark knock. low octane fuel takes less pressure to detonate. so when you have a high compression engine with low octane fuel it detonates before the piston has reached top dead center. with low octane fuel it becomes unstable as the pressure inside the cyliner increases. you dont have to worry about going up in octane as long as it is unleaded. if you use a race fuel that is leaded it wont damage your engine but will more than likely burn up your o2 sensors. hope this helps.
No that is not likely.
Low octane fuel, Incorrect timing, Over heating,
Autoignition
It sounds to me you are using a fuel to low in octane, either that or your timing is wrong. Try running on 95 or higher octane fuel.