My brother rides an 08 Vulcan Nomad. Since purchase his bike has pinged, sometimes pretty bad. He installed a TFI and says he now runs 87 octane with no pinging. I told him not a good idea, his bike was designed for 93 and he should run it. He got online with a forum and read since bike is now running richer he can run a lower grade fuel. He wanted to hear that cause he is cheap and tries to squeeze a penny until it bleeds. I think in the long run it could damage his bike, but don't know enough to convince him. Am I right?? Will it damage his bike? or is he gonna be ok running low grade? thanx.