I recently purchased a 1987 FXLR, without an owner's manual. What octane is recommended for a 1987 1340 Evo engine? Thanks for your input.

 

With todays fuels, I would run 93 or 91 in the bike depending on where you live. Chad

 

My owners manual said 89 for a 95FLSTN eve

 

I recommend 92/93 octane.

 

Run the lowest grade you can run without any detonation.

 

I can only give you advice I received when I was racing. It came from the Ducati mechanic that was on loan to the company that distributed Ducati, Moto Guzzi and Norton back then that I worked for. He still spends winters in Italy doing engine development and fields his own teams here during the racing season. I guess you'd say he knows what the's talking about.
At the time I was getting 110 octane from a friend in the Air Force and using it in my bikes.

What he told me was to start with a lower octane, if it knocked go to the next higher octane etc. till the knocking stopped.
His reasoning was that riders used the higher octane believing they'd get better performance but in actuality what they were doing was shortening the life of the engine if it was not built to take the added stress and heat that was created by the higher octanes. Worked for me and I still have my enduro bike from the 70's that has 48k on the clock and still great compression on the original bore. That and Castro GTX oil changed frequently.

One other thing he told me as I uncrated one of my brand new Ducatis back then was that I should do the break in like I meant to ride it. I told him I rode hard. He said OK, break it in that way and I did. Never had a problem with that machine nor did the 2 subsequent owners.

Blacky