High octane

[robertbarr]

I've also read that it takes a gallon or so of the previously pumped fuel to move through the pump & hoses before you start getting your premium fuel. Not a big deal for most vehicles that might take on 15 gallons, but for a bike, a different story. Buying five bucks of premium might get you pretty much what you'd get if you bought regular.

So, if you purchase premium, the next person to use that pump gets a gallon (or so) of premium for the price of regular.

[koolaid_kid]

My GS would knock continuously on 87 octane. On 91, only once in a while. on 93, never.
Made for tough times on rallies when we stopped in tiny hamlets where only 87 was available.

[wymple]

My 82 GS1100 would ping in very hot weather. Ethanol worked better than regular, but still got a little ping if it was hot weather. I got in the habit of using a station that sold "Turbo Blue" racing fuel. I put in one gallon and topped the tank off with regular. The pinging was history. Did it for years.

[Katarat]

If its at all possible I use the alcohol free premium they have here in Montana. Not because of the octane but because of what the alcohol does to the carbs

[dorkburger]

Not to turn this into a pods vs not thread, but ive often wondered what affect the pods sucking in hot air from directly behind the cylinders has, If any, on detonation......

[Steve]

... Now I've just read this recent post:

"Since higher-octane "premium" fuel burns slower, you need to advance the timing several degrees to get it to complete its burn in time.
With stock timing and "premium" fuel, the mixture is not being completely burned, robbing you of power.
My suggestion here is to go with the factory-recommended "regular" fuel."

Thoughts, comments? ...

I am the source that you quoted.

I don't remember the exact source of my information, and it was a LONG time ago, but it was an education about higher-performance automotive engines and the use (or requirement) of higher-octane fuels.

First off, the article mentioned that high-octane ("premium") gasoline actually contains fewer BTUs per gallon than "regular" gas. That alone will tell you that you will get fewer miles per gallon. The article went on to say that as compression figures went up on an engine, the temperature of the compressed mixture also went up. Sometimes it would be high enough to ignite the incoming fuel mixture. Higher-octane fuels would resist that pre-ignition and required the spark to light the mix. Higher-octane fuels also burned slower, and since there is a need to finish combusion by a certain point in the crankshaft rotation, it was necessary to advance the ignition timing to get it all burned in time.

Note that the higher-octane fuels and the advanced ignition timing are "Band-Aids" that allow you to use higher compression in the engine. It is the higher compression that makes the power, the gas and timing just let you use that compression.
nee
If follows reason that since the timing needs to be advanced to complete the combustion at the proper time, if you don't advance the timing, you will be losing some efficiency. And, since there are fewer BTUs in the first place, you are losing even MORE efficiency.

Simply putting "premium" fuel in the tank might lead to deposits of unburned fuel on the tops of the pistons and on the valves. Eventually, you will need to run "premium" becaue the deposits are glowing and lighting mixture.

.

Not to turn this into a pods vs not thread, but ive often wondered what affect the pods sucking in hot air from directly behind the cylinders has, If any, on detonation......

Not to worry there, if you have a stock airbox, it draws in the same warm air just a few more inches 'downstream'.

.

[blowerbike]

Not to turn this into a pods vs not thread, but ive often wondered what affect the pods sucking in hot air from directly behind the cylinders has, If any, on detonation......

none that i (on my bikes) or any bikes i have done st.3 kits have every noticed.

[GSX1000E]

I've also read that it takes a gallon or so of the previously pumped fuel to move through the pump & hoses before you start getting your premium fuel. Not a big deal for most vehicles that might take on 15 gallons, but for a bike, a different story. Buying five bucks of premium might get you pretty much what you'd get if you bought regular.

So, if you purchase premium, the next person to use that pump gets a gallon (or so) of premium for the price of regular.

All true. I recommend looking for stations with individual hoses for each grade such as Chevron and Shell so that you get what you are paying for.