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It may seem like a stupid question but I'm curious about octane recommendations, I read on lower compression bikes 91 octane is not good for combustion. I filled the tank with 91 and noticed it seems sluggish. Currently the third owner of the bike and the gentleman before me took it out maybe a hand full of times during the summer. I'm curious if it needs a carb tune or if 91 just is not the way to go. Just curious what octane is recommended.
 

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It may seem like a stupid question but I'm curious about octane recommendations, I read on lower compression bikes 91 octane is not good for combustion. I filled the tank with 91 and noticed it seems sluggish. Currently the third owner of the bike and the gentleman before me took it out maybe a hand full of times during the summer. I'm curious if it needs a carb tune or if 91 just is not the way to go. Just curious what octane is recommended.
My sv1000 I run mine on 91 and have found i get the best mileage, feels fine to ride (engine performance feels the nicest) and when i check spark plugs they don't show as lean.

I do occasionally run a tank or two of 98 through originally due risk of carbon buildup but have seen an SV that was run on 98 and had cylinder carbon buildup and when they ran a lower octane they didnt....
When on 98 mine feels slightly sluggish.

Overall though i think it comes down to the additives and simply what your bike was originally tuned as from the factory.
E.g. a mate had all sorts of dramas with a regular 98 fuel but found a 95 ethanol blend that his bike performs nicer with, no idle struggle or pinging etc. That was a CBR though.

Sent from my SM-G965F using Tapatalk
 

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The 650s are not fuel-sensitive. In the UK, the minimum octane rating you can buy at the pump is 95RON (equivalent to 91/92 by the US rating method) with 5% ethanol.

We also have 99RON premium fuel (equivalent to 95/96 US, 5% ethanol). I never noticed any difference between them in performance or economy in either of my SVs.
 

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No reason to run anything other than 87 octane Regular in the SV650.

I always run ethanol-free 87, but technically you make more power with ethanol-gas when the mixtures are both optimized.
 

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Higher Octane rating means the fuel is less prone to detonation. So contrary to popular belief, higher octane fuel will make your bike weaker, not stronger, since it will combust less efficiently and not as designed by the engineers who built the bike and tuned the fuel injection. Get the minimum octane rating your manual calls for.

The only reason to get higher octane fuel is for the additives they advertise to justify the drastic increase in price. However there are no independent studies as far as I know that prove these additives have any noticeable effect on your engine's longevity.

More important is to get fresh fuel from a gas station with clean tanks. Plain old regular is the most used type of fuel, so it usually will be fresh. Also fuel up at a well frequented gas station that adheres to a quality standard set by auto manufacturers:
 

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No reason to run anything other than 87 octane Regular in the SV650.

I always run ethanol-free 87, but technically you make more power with ethanol-gas when the mixtures are both optimized.
How about an explanation of that last sentence, it's a little confusing.
 

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How about an explanation of that last sentence, it's a little confusing.
"but technically you make more power with ethanol-gas when the mixtures are both optimized. "

I doubted this myself at one point, but was corrected.

Gas with ethanol does provide more HP than gas without ethanol if the air/fuel ratio of both are optimized (optimum air/fuel ratios won't be the same unless adjustments are made).
 

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I think I know what you're referring to because car tuners will blend higher than normal amounts of ethanol in order to get a higher total octane rating to keep from blowing up their turbocharged engines, but if one is using pump gas (straight "regular" gas or regular with 10% ethanol) it doesn't work. On a 87 octane blend of gas the refiners blend to an octane rating of 85 or 85.5 then when the ethanol is added at the truck loading rack the final product will add up to an octane rating of 87. Refiners don't like to "give away" octane, and this saves them a ton of money.
 

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I think I know what you're referring to because car tuners will blend higher than normal amounts of ethanol in order to get a higher total octane rating to keep from blowing up their turbocharged engines, but if one is using pump gas (straight "regular" gas or regular with 10% ethanol) it doesn't work. On a 87 octane blend of gas the refiners blend to an octane rating of 85 or 85.5 then when the ethanol is added at the truck loading rack the final product will add up to an octane rating of 87. Refiners don't like to "give away" octane, and this saves them a ton of money.
I understand what you mean - you're right.

The tests I saw were done by adding ethanol to gas, so it would have bumped the octane.

They changed the jetting and ignition timing, and made more power - but that could have been due to the octane increase in that situation.

I would like to see back to back tests of E10 vs non-ethanol fuel (both "Regular" 87 octane) to see how they compare. You would need to be able to adjust the air/fuel to really know.
 

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As stated, higher octane is to resist pre-ignition/detonation /pinking /knocking /whatever term your used to. To answer OP question run the lowest octane that is recommended for your bike that doesn't knock/ pink/pre- ignite/ detonate. Otherwise your just chucking money out the exhaust.
 
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I think I know what you're referring to because car tuners will blend higher than normal amounts of ethanol in order to get a higher total octane rating to keep from blowing up their turbocharged engines, but if one is using pump gas (straight "regular" gas or regular with 10% ethanol) it doesn't work. On a 87 octane blend of gas the refiners blend to an octane rating of 85 or 85.5 then when the ethanol is added at the truck loading rack the final product will add up to an octane rating of 87. Refiners don't like to "give away" octane, and this saves them a ton of money.
where do you get this stuff?
 

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Most anywhere, or any region that requires a ten percent blend of ethanol in the gasoline.
Most anywhere, or any region that requires a ten percent blend of ethanol in the gasoline.
Most anywhere, or any region that requires a ten percent blend of ethanol in the gasoline.
Most anywhere, or any region that requires a ten percent blend of ethanol in the gasoline.
not that stuff.....your information!
 

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As someone who just spend $400 towing their bike back home with a truck rental I'd say just mainly avoid using backwoods gas stations if you can. Just flushed my high pressure fuel filter at 60k miles and the amount of grime in there was shocking to say the least.
 
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