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93 oct gas

Honest Abe said:
+1
Just learned that my bike likes higher than 93 octane. I live in northern california and recently found out how to get higher than 91 octane. I mix 91 and 100 octane 50/50 runnign about 95-96 octane, and I can swear it is like riding a different bike.

My bike and I both are much happier with higher octane!:)
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It's not the best thing for your valves running that high of an octane.
 
Most mid end cars like BMW recomend Premium fuel, so the pumps are most likely turning over the tanks on a regular basis. We have 93 in MI so that is what I use. The couple times on trips I used 91 I can't say I noticed a difference.
 
Sometimes you just don't have a choice and gotta use what you find. At least with a 3.3 gallon tank on the Sporty, that's what I do. But, for the most part, I use what's recommended or a little better and fuel up at a big national brand station that sees a lot of traffic.

I've experiemented a bit and found some improvement going with mid grade fuel.(from 87 to 89, manual calls for 87) When I tried the high test (91), didn't notice a difference from the mid-grade. I get a little bit of knock pulling from a stop with the factory recommended rating.(87) None with the mid grade.(89)

10 year old machine, no internal mods. Just Stage 1 filter and slip ons and jetting to suit. It seems to me, there is more various octane fuels/ratings in the USA than the great white north so, take this with a grain of salt.

As others have cautioned on the potential harm of using too high of octane rating, I think it's just money burned up that could have been spent on bling or mods. I just wouldn't go straight to the highest possible octane just because.........


I don't sweat the details of what's left in the hose before or after. Twist the grip and ride.

Cheers.
 
93 Octane...? Whats that...(LOL)??? In California you can get 91 Octane, 89 Octane and 87 Octane that is "seasonally adjusted" for Winter and Summer formulae. I run mildly tuned stock machines w/ Stage I typically. So with one or two grades down from premium with no ill effects I am all for saving a little bit by finding which grade my bike starts to ping...then go one grade higher. When on the road, go to busiest gas station and run premium 91 octane and like Bubbie, never gas up if you see the tanker there to fill the underground tanks.

Never ran 93 Octane, nor have I found any here in SoCal. I just spend the time to determine what octane rating and brand runs best in my machines and stick with it. I have found 89 Octane runs fine in my high performance Sportbike, unless I intend to go on long trips 2-Up or spirited rides where pinging could occur. My Harley runs fine on 89 Octane or if solo for in town 87 Octane does not ping either, even with strong thottle, just feels a bit sluggish when I "wick it a bit".

93 Octane should be fine, but you would probably do even better with 91 or 89 Octane, cheaper and if it does not ping with heavy throttle or two-up riding. Changing ROH rating is like adjusting the overall timing a few degrees, so spend the time to find which grade causes the bike to ping worst case...and go one octane rating higher and do run a few tankfuls to be sure.
 
You don't need to worry about 'stale' gas in modern stations

The gas all comes from the same tanks and is blended right at the pump. While a older mom&pop station is always a risk, the newer modern stations blend the different grades right at the pump. If there is any residual gas after the previous customer it is maybe a couple of ounces at the most. We have 94 oct here in BC and it has its own tanks since it contains no ethanol......yet. Chevron will continue to provide this until the demand becomes so small is is un-economical to produce.
Caveat- do not fill your machines while the truck is refilling the tanks, or within an hour either. The sludge that collects at the bottom of any tank is stirred up during the filling process.
 
Straight from the owner's manual...is table 18, 1 entry only, that specifies 91 octane fuel, no mention of minimum or maximum octane. This is for a 96 cu.in.
I am more concerned with the amount of ethanol blended, the manual specifically states not to use more than a 10% blend. I have read several posts here that some states will allow a 15% blend soon.
 
Using a higher than recommended octane like racing fuel or other octane rated fuels of 100 or more in any motor will result a slower burn. Your engine management system will retard spark to try to eliminate the knock from the slow burning fuel and can remove more timing than is necessary to avoid knock. The ION sensing in the Harley engines will perform this task but will pull more timing than usual to stop knock from the slow burn of the 100+ octane negating most benefits arrived at with the higher octane and more expensive fuel.
Spark control in the engine management program will try to have a complete burn by a pre determined point after top dead center usually around 10*and the higher octane racing fuels will burn slow enough to damage valves by a slower burning than a regular fuel and can be still burning at the time of the exhaust valve opening which will form carbon deposits on the valve and prevent a seal when closed, This would result in overheated and burnt valves. The rest is obvious.
Engines that require a higher octane than 93 usually have a compression ratio in excess of 10-1 that would make the bike not very streetable and more suited for a track motor.

I don't recommend any octane higher than 93 and I only use 93 in all motors I own. The modern day fuels use a rating of "research octane" which isn't rated like the older fuels of years ago that actually rated the fuel for it's properties.

If you don't agree, then run some avgas or racing fuel for a period of time and let us know the outcome.
 
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