That's what I'm thinking. I normally run 93 in the Roadking and it is very smooth. When I have put 87 in it will run rough.

The sporty will run like crap with 87. It does ok on 93 and just loves 100LL (aviation gas).

 

My sporty runs well on 95 - 100LL would be good to try but wallet busting here in the UK.

 

When detonation is detected the spark is only retarded momentarily. On of the most famous Corvette engineers for race tuning Corvettes told everyone at a seminar that unless you were at the strip or on a race track that high octane was a total waste. Corvette like HD suggests 91 octane.

I run 89)which is the lowest in this area of 89-91-93 in all my HD's (5), Corvettes(3) and a Viper without ever experiencing pinging. I can run them through the gears with a lot of gas pedal. Never had them ping.

I will go by what the trained and experienced experts say.

 

We,, son and I only use 92,or 93 oct here never had problem,,,

Did get some water 2yrs ago in the fall, gas treatment took care of that..

 

You never know today,Ethanol,water,who knows what else flows out of the nozzle.Try a known good tank of fuel and see if it smooths out.

 

Bad gas or you dropped something in the tank possible... basically all I run is 93, you can't even get 91 in NY except for select stations here or there (some Sunoco's), premium here is all 93... never had a problem.

 

Probably bad gas. However, I was amazed to find that engines get "used to" a particular grade with the new engine management systems. When gas got high I switched to lowest octane in my cage. It occasionally pinged and complained during acceleration for a couple of weeks and then gradually smoothed out and ran perfectly. The transition was not immediate.

 

At high-altitude, you don't get the sea-level range of 87-93 at gas stations. You get 85.5-91.

That's why it was so unusual to find a place selling 93 around here.

 

Hmm...

Interesting thread with lots to think about.

In my area, the most common combination of octanes is 87-89-93 and almost always it is 10% ethanol.

With cars I have always understood that if it says "Recommended" then I don't necessarily need to use the rating it suggests. I noticed that my H-D owner's manual also reads "Recommended" when it says to use 91 in my bike. As a first time scoot owner, I did not want to take chances but I also didn't want to spend as much on gas riding my Harley as I do riding my car because I have to use the most expensive fuel. I decided to compromise and I use the 89 and have done so almost exclusively. As far as I can tell I have not had any problems at all. I am going on almost two years of owning my bike and I ride an average of about 240-300 miles a week. I have never put anything less than 89 and on several occasions when there is a good drop in price I may splurge and get the 93 but honestly, I have never seen any improvement or determent to the higher octane. Is it because I have to run it for some time before such changes are noticeable?

 

Will that my friend was a good one! LOL