My ride is a 1980 thousand CC Ironhead and the Harley manual says I should get high quality premium gas that is 94 octain or slightly more. Since ethanol came out the premium available has mostly been just 90 octain.
   I use a S and S Super E carburator. I tried to change the jets at first but that was the wrong idea. While using the wrong jets I tried some Sea Foam but with the wrong jets that didn't seam to help.
   I heard about Star Tron on line and found out it was available at Southern Cycles. I could also get it at an auto dealer. It really seams to work not that the original jets are in use gain. It just didn't seam to run like it had when premiu had more octain in it.
   Searching online I stumbled upon Lucas Octain Booster offered at JP Cycle. I lucked out because it was also offered by a local auto parts dealer. The phone number on the bottle let me speak to a technitian and find out how much to mix with the two and a half gallons my fuel tanks hold. I was told 1.5 fluid ounces  would make a high 43octain.
   I've even talked to other riders who have used it in some old hot rod cars. The technutian even told be I can still use star tron and octain booster can get mixed in the gas at any time.
   I've heard Lucas also make Sea Foam and that can be used to fight ethanol. I've used that before, once a month in a pickup truck and have heard it also has octain in it.
   I'm still having to be carefull because I have been told not to make the octain level too high. 97 and 100 is too high.

I used it years ago when I traveled to Sturgis and in some areas couldn't find anything higher than 89. It actually came in a bottle specifically made for 5 gallon gas tank.

I buy something, I think it is, called Nitro. It is designed 1 ounce per gallon. Usually on the back it will break it down. Does it help? Who knows, I do not think I really notice a difference when I use any of the additives. But for the money it is worth it to believe it might and use it.