After doing some research I can see that 91 octane helps with pre ignition, which by the way my wife is glad we have now put that behind us. Will using a lesser octane do any other damage to the motor? My car recommends 91 and I use a lower grade without any significant performance difference or damage after 140k miles.
Just wondering.

After doing some research I can see that 91 octane helps with pre ignition, which by the way my wife is glad we have now put that behind us. Will using a lesser octane do any other damage to the motor? My car recommends 91 and I use a lower grade without any significant performance difference or damage after 140k miles.
Just wondering.

89 might work or might not.  Depends on several things including temperature, with some people saying their Liners are okay with it in winter but they get knocking during summer.

I did the fill up one day 2/3 a tank of 87, the bike ran ok, but seamed to run a little hoter and the gas milage dropped some. that was the only time.

I run mid or regular fuel a lot. No issues, no pinging. Chevron 91 or 89 seems to me to make no difference..even 87. Just my experience