Yes, less oil in the fuel can cause serious problems . The extremely rich fuel/oil ratio these engines run is to protect them at high rpm’s where heat and friction can destroy an engine quickly. If you aren’t comfortable with pulling the head of your engine yourself , pull off the exhaust pipe and header , look in thru the exhaust port and inspect the cylinder visually and see if there is any scoring, galling etc. Also pull the spark plug out so there is no compression and turn the engine over while looking thru the exhaust port. Look closely at the piston as it travels by, usually the first signs of damage show up on the exhaust side of the piston and cylinder as that is the hotter side. Hopefully everything is ok. The higher octane in fuel prevents detonation in an engine , also called spark knock. It usually shows up under high load, high rpm conditions just like you have when racing wide open. Detonation can destroy an engine. If your engine seemed to run ok except at high rpm you could have been experiencing detonation, and switching back to 110 octane race fuel should stop that. Hopefully you have no engine damage.
