I will be the first to admit I don't know much about engines. I can change my oil and do a few other things, but that is about it for my mechanical skills and knowledge.

The owners manual for my new BMW suggests super unleaded (89 octane) but the book also shows "with regular unleaded" which is 87 octane.

I also know many bike owners who only put premium in their bikes.

So... am I hurting the bike by running 87? Is it even better to run 91?

What they are saying is, "for best results run hi-test, bike will run fine on regular because the computer will adjust accordingly".
(maybe a little less (hp) performance with reg..)

I always run Hi-test in my C14 because that's the only grade they mention.

So... am I hurting the bike by running 87? Is it even better to run 91?

From Edmunds....

If you're in doubt about switching to a lower-octane fuel, here's a deeper explanation of why the change is unlikely to hurt your motor.

Premium gas is more expensive because it contains a higher percentage of octane. Why is this important? When vaporized gas mixes with air and fills the combustion chamber, it is compressed by the rising pistons. This makes the gas-air mixture grow hot and it could ignite before the spark plug fires, pushing backward on the piston. Higher-octane fuels can be compressed to a greater degree without self-igniting. That's why premium gas is used in high-performance engines.

In the old days, engines could not adjust to fuels with varying octane ratings. Use the wrong fuel and the engine would knock or "ping" audibly because the gas exploded prematurely. This knocking damaged internal engine components over time.
Today, engine control systems can compensate for low octane by monitoring knock activity and adjusting ignition advance to avoid knocking. This sophisticated electronic capability effectively tunes the engine on the fly and gives drivers more flexibility in the grade of fuels that they can safely use.

Compared to premium gasoline, lower-octane fuels don't allow the engine to run as much ignition advance during situations calling for rapid acceleration. More ignition advance allows the engine to make more power, and accelerate more quickly, during these conditions. Since the engine doesn't make quite as much power with lower-octane fuels, this translates into slower acceleration in cars for which premium fuel is recommended. The performance loss is especially noticeable in turbocharged gasoline engines, which have become increasingly popular in recent years.

The performance loss, however, is something you will only notice if you flog the bike and accelerate rapidly from a dead stop or while changing lanes at highway speeds. But if you accelerate moderately, the loss of power is barely noticeable, regardless of whether you use premium or regular-grade fuel.

Use premium.

After doing some additional research I discovered Missouri requires 10% ethanol to be blended into all gas EXCEPT premium, so I will go with your suggestion.

Ethanol Blend Mandate

All gasoline offered for sale at retail stations within the state must contain 10% ethanol (E10). This requirement is waived only if a distributor is unable to purchase ethanol or ethanol-blended gasoline at the same or lower price as unblended gasoline. Premium gasoline is exempt from this requirement. Ethanol is defined as fuel that is derived from an agricultural source and that meets ASTM specification D4806. (Reference Missouri Revised Statutes 414.255)

New bike, so;
Run it on 89 until it's broken in and you're familiar with how it runs, sounds, rides, performs, etc.  Record your mileage.
Then;
Run run a few tanks of 87.  Note any differences - mileage is the one that can be compared with hard data.
Oh,
And enjoy!!

Quote from: Stripes on January 09, 2014, 07:27:55 AM

Use premium.

After doing some additional research I discovered Missouri requires 10% (soon to be 15%) ethanol to be blended into all gas EXCEPT premium, so I will go with your suggestion.

Meh.  Everything has ethanol these days and has for years and years around here.  The only way I'd pay more for premium with no ethanol is if the increase in MPG justified the difference in price at the pump.  Odds are it doesn't.   

When i first got the FJR i was running premium but when the price of gas went up i started running 87. 272,000 and no problems. When it gets hot out i do get a little nock when acseletaring off of low end but not an issue. When it gets hot out (85+) i will run 87 or 91 octane.

Quote from: Stripes on January 09, 2014, 07:27:55 AM

Use premium.

There's no benefit in running an octane higher than what's recommended.

IMO, run what the bike calls for.  Which, in this case, is 89 (mostly called "plus").

EDIT: Oops, moderator error. I clicked on the wrong post to edit.

This, all day long.

Unless, as in your situation, hi-test contains reduced or no ethonal, in which case, it would be worth while to test performance (mostly milage) with that . . . .


Running higher than suggested octane buys you nothing at all. Octane is simply an indication of the fuel's resistance to pre-ignition.

In NY all gas has ethanol now so no benefit of Super unless called for.  I run the cheapest I can in all my stuff.  My car calls for 91, so in my car its the 91 or higher.  Any knocking or pinging and I go up to the next octane grade.  No better performance based on octane, just raises combustion temp.

If I had the option of no ethanol in only one grade, I would run that. 

Quote from: Black Hills on January 09, 2014, 09:15:41 AM

Quote from: bomber on January 09, 2014, 09:08:17 AM

Running higher than suggested octane buys you nothing at all. Octane is simply an indication of the fuel's resistance to pre-ignition.

 I agree with this and understand the science behind it to some degree. But, why does my 2 stroke dirt bike run sooo damn good on 1/2 pump and 1/2 AV gas??

Maybe no ethanol in the AV gas?

 it runs noticeably better than 93 octane w/o ethanol too?

Assuming it's a US model you would hope they give the rating we use in this market.

Quote from: Cablebandit on January 09, 2014, 09:52:33 AM

Assuming it's a US model you would hope they give the rating we use in this market.

My US model specifies RON on the tank (IIRC) and has others listed in the manual.



In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).

Gotcha.  All my bike warning stickers come off once I get home from the dealer.  I don't want the death reminder. 

I'm aware of all the different grade/methods. 

Oh, if you try 87 and it doesn't quite do it you could always step up to 87.5

visitors can't see pics , please register or login

That has to be at least 0.5 better! a difference you can FEEL!

That's what you should run in that wethead you just bought.

That is just a rumor! -which may or may not be true. 

That was from a few years ago on a trip down to Merlin*.








* Maryland

Geeze, it's an F700. I doubt the engine was tuned for high performance fuels

Seriously, put regular in it. If it knocks or pings, then use the good stuff. Unless the engine has a knock sensor, which most bikes don't, it will not adjust for lower octane.

Edit: a quick internet search confirms the f700gs does not have a knock sensor. So yeah, if low octane runs crappy, use the 89.

Doesn't the octane of gas you choose depend on the oil specs?

 

Quote from: Justin on January 09, 2014, 12:18:29 PM

Geeze, it's an F700. I doubt the engine was tuned for high performance fuels

Seriously, put regular in it. If it knocks or pings, then use the good stuff. Unless the engine has a knock sensor, which most bikes don't, it will not adjust for lower octane.

Edit: a quick internet search confirms the f700gs does not have a knock sensor. So yeah, if low octane runs crappy, use the 89.

Does it have to have a knock sensor? Won't the sensors in the exhaust detect a burn condition that indicates pre-ignition? The 1200 manual states you can use lower octane but the engine will compensate and power output will go down.

This is ST.o, and we won't let this die until every dead horse if thoroughly flogged.

I believe the 1200 actually has a knock sensor.

Quote from: Justin on January 09, 2014, 01:32:27 PM

I believe the 1200 actually has a knock sensor.

Letting you know if someone make fun of your bike?

One the Vstrom that sensor is a handy light near the front- when it's lit, you know someone is knocking your bike:
visitors can't see pics , please register or login

Try this:

https://mn.gov/commerce/weights-and-measures/images/OctaneFacts.pdf

Use premium.

Both my bikes call for premium gas in the manual, so that's what I use. Bikes get great mileage anyway, so I think nothing of the small amount extra I pay.

My Fjr has used 87 since it was new.  Our rating system is diferent but as to how different, I don't know.  I run the WR250R on premium.  If it wasn't available when I filled up I would put 87 until I could put premium next time or to top it back up.  It blows up.... it blows up.   

don't forget elevation plays into the mix as well

Use what the manufacturers manual recommended!

Use premium!