In a car pre-detonation is heard in the form of 'pinging' and 'rattling'. I used to drive a Ford patrol car that did this anytime you got over 1/2 throttle. I wanted to burn premium fuel in it to help prevent this, the State (who actually owned the car) said they didn't want us putting premium octane in the car. Their car, their decision, no matter how stupid it was. Pre-detonation can be prevented, in some cases, by burning a higher octane fuel. Contrary to popular opinion, a higher octane fuel is not as 'hot' as a lower octane fuel. Most people don't believe that, it's true, trust me. If you run a low octane 87 fuel and have a pre-detonation condition and then switch to a 93 octane and it goes away that is because the 93 octane is not pre-detonating, ie, it has a higher igntion point than the 87 octane. Octane ratings indicate the fuels resistance to ignite. Lower octanes will ignite quicker than higher octanes. Most all of us have added some kind of aftermarket pipes to our beloved LC. Lotsa noise, sounds cool, I love it. The trade-off is that I am not sure that you could hear the 'pinging' and 'rattling' of pre-detonation. I've never heard it on my bike, but I drove away from the dealer with V&H pipes installed. Since you can't hear the pinging (least I am not sure you can) of pre-detonation I am a little bit leary of stepping up the ignition advance a great amount, but I wanted to step it up some, after all tinkering is 1/2 of what having my LC is all about. Continued...