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2009 Shadow Spirit 750
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Discussion Starter · #1 ·
Saw an old thread on here... didn't want to dig up the past...
I've googled, etc. Unfortunately I don't have an OEM Owner's manual for my '09 Spirit 750.
I do have a good understanding of the different octanes and their correlation to specific engine (design).

Can anyone with an owner's manual or first hand actual knowledge state what Octane is factory recommended for our shadows?
I've typically always ran premium in my bike just in case and never had any apparent issues with it... and being a small tank, a few extra cents doesn't break the bank.

Now if I was filling up my old Jeep... with a 20+ gallon tank... that's a different story.. and fortunately it's old and is recommended to run on 87 all day long.

I always tend to run Shell brand in all of our vehicles.. (bike, Jeep, wife's car). Just because I like the detergent/cleaner package they use over other brands. But these days, whatever isn't costing an arm and a leg plus your first borne. lol.
 

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Be aware that manuals for different markets might have different numbers, because local jurisdictions measure fuel octane differently.

This Honda VT750C manual from 2007 states 91 RON, (Research Octane Number) Honda VT750C Owner's Manual (Page 40 of 135) | ManualsLib
which is roughly equivalent to 87 AKI, which is the average of RON and MON, (motor octane number),
I believe that AKI is what appears on gas pumps in the USA. Complicated right?!

This suggests to me that regular gas would be fine in your bike. Honda didn't give the Shadows particularly high compression, and the dual spark system is intended to counter detonation.
 

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I had a sneaking suspicion that it would be 87... but tossed this out there to get confirmation.
Not that folks don't have valid reasons for running premium, especially if they have experienced pinging while running regular.

Premium can even be more economical for some people, (although I doubt this will be case any more, with premium about $1 more per gallon, or 20% higher cost than regular, locally) . Two cases where premium could possibly be more economical, would be 1) if the premium didn't contain ethanol, but regular did. Ethanol has about 1/3 less energy per unit volume than pure gasoline. Or, 2) If the engine was computer controlled, and automatically retarded timing to avoid pinging, then fuel economy can really suffer. This second case isn't your carbureted Shadow though.

The bottom line, in my opinion is miles per dollar. Do a controlled test with premium and regular and find out what is what! There's also such a thing as mid-grade. And gasoline isn't uniform. It can vary from lot to lot, (there are tolerances on the formulations), and decline in quality over time even while sitting in storage. Ethanol content doesn't help with this, it attracts water molecules.

Pinging will usually show up, in my experience at high engine rpms and high loads, a long uphill run on a highway at top speed in hot weather, for example. If you don't get it then, you probably won't get it ever. If you do, back off on the throttle. Each ping can put a tiny divot in the top of your piston.
 

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Be aware that manuals for different markets might have different numbers, because local jurisdictions measure fuel octane differently.

This Honda VT750C manual from 2007 states 91 RON, (Research Octane Number) Honda VT750C Owner's Manual (Page 40 of 135) | ManualsLib
which is roughly equivalent to 87 AKI, which is the average of RON and MON, (motor octane number),
I believe that AKI is what appears on gas pumps in the USA. Complicated right?!

This suggests to me that regular gas would be fine in your bike. Honda didn't give the Shadows particularly high compression, and the dual spark system is intended to counter detonation.
All US gas stations use the same octane spec.
 

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2009 Shadow Spirit 750
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Discussion Starter · #6 ·
I remember 10-12 years ago where I lived at that time, there were still 2 stations near town that sold straight gasoline... not that worthless Ethanol blend garbage.
To me their "on the books" reasons for Ethanol fuels are invalid.... and has NO positive affect on the environment as a whole.
Fact: the Ethel-alcohol produces approx. 30% less energy than straight gasoline when burned.
Fact: Is proven to be corrosive to internal parts within the fuel system and engine. (because Ethel-alcohol is hydroscopic it attracts moisture from the air aka. water).... leading to said corrosive issues.
Fact: will cause at least all vehicles built before the introduction of Ethanol blended fuels to prematurely become damaged internally because they were not designed to burn that type of fuel. (this one may actually be part of their plan, only they know)
Just like burning regular unleaded gasoline in an engine that required a Lead additive (remember those?) It won't kill it overnight...but will prematurely wear out internal parts.
Fact: Because of being forced into this type of fuel in our vehicles... the affect on the environment is the same if not a little worse because we still have to get from A to B...and if it's 30% less efficient, we have to burn 30% more in order to go the same distance. Don't need to be a rocket scientist to do that kind of math. LOL.
The last fact...is why Washington's argument for these fuels is invalid. If they were really the peaceful, tree hugging, polar ice caps melting people they say they are... they would put their greed aside for a moment and actually make the accurate choice.
Seems to me that a lot of the time they're just trying to sell us lipstick on a greased pig.
Okay... rant over. LOL.
 

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Wow, a reasonable question re factory recommended fuel pivoted to an ethanol rant that was somewhat relative about 30 years ago. I have some of the oldest bikes owned on this forum and started using methanol and then ethanol 10% blends in 1988 so about 34 years ago and still running strong. As far as Shadows: 1995 VT1100C2 and 1999 VT750DC have used nothing but E10. The 1995 had its carbs off in 1996 when I installed a Dynojet carb kit but no engine/carb work for 25 years and the VT750 has never had its carbs off. Both bikes are stored 6-8 months every year.
 

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I remember 10-12 years ago where I lived at that time, there were still 2 stations near town that sold straight gasoline... not that worthless Ethanol blend garbage.
To me their "on the books" reasons for Ethanol fuels are invalid.... and has NO positive affect on the environment as a whole.
Fact: the Ethel-alcohol produces approx. 30% less energy than straight gasoline when burned.
Fact: Is proven to be corrosive to internal parts within the fuel system and engine. (because Ethel-alcohol is hydroscopic it attracts moisture from the air aka. water).... leading to said corrosive issues.
Fact: will cause at least all vehicles built before the introduction of Ethanol blended fuels to prematurely become damaged internally because they were not designed to burn that type of fuel. (this one may actually be part of their plan, only they know)
Just like burning regular unleaded gasoline in an engine that required a Lead additive (remember those?) It won't kill it overnight...but will prematurely wear out internal parts.
Fact: Because of being forced into this type of fuel in our vehicles... the affect on the environment is the same if not a little worse because we still have to get from A to B...and if it's 30% less efficient, we have to burn 30% more in order to go the same distance. Don't need to be a rocket scientist to do that kind of math. LOL.
The last fact...is why Washington's argument for these fuels is invalid. .
This source discusses the history of ethanol use as fuel. History of Ethanol Production and Policy — Energy (ndsu.edu)

Although it has been blended with gasoline for 100 years, I've read that real push to mandated ethanol content in fuel was not primarily for environmental reasons but to promote national energy independence. It's a fuel that can be grown, not mined from presumably limited resources millions of years old. It still makes sense in terms of long term sustainability. If you bury some ferns today, the lead time on them turning into crude oil is a couple million years.

Mixed in at 10%, with the major proportion being, in theory, gasoline, the BTU content is only reduced by ~3.5% ( 10% of 30%) I've seen experimental results that suggest efficiency loss may be up to twice that, but I can't account for why, perhaps it is the hygroscopic nature. Water content won't be burned, but it will be vaporized and that will consume energy.

A vehicle would probably have to be from the early 70s to suffer from unleaded fuel. Preserving one of these as a collector's item is good fun, but I can't imagine being able to afford using the 10 mpg, 1972 Buick I owned back in the day, as a daily driver. Ethanol blended at moderate percentages shouldn't be a problem for any vehicle less than 40 years old.

I won't argue that pure gasoline isn't more stable, or easier to use. Ethanol blend is what we have. Enjoy it while you can.
 

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In the end, those in power will do what they do, for their own reasons. Critics can call them ‘stupid’ or ‘uninformed’. Trust me, they’re not. They know, and have experts that keep them informed. Not much else we think or say matters…

So yeah, factory spec is regular ‘87’, and the only benefit of ’91’ would be if it was Ethanol-free. If you ride enough, and properly store the bikes for long periods, the Ethanol isn’t as much of a consideration. For an EFI system, ’91’ will usually run more efficiently, as it does in my cars. However, there have been exceptions. The ‘98-‘00 Honda Accord V6 ran like GARBAGE on ‘91’. Nobody knows just why… 🤔

As for the energy volume corrections, well, have you bought a package of cookies lately? 😄
 

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Saw an old thread on here... didn't want to dig up the past...
I've googled, etc. Unfortunately I don't have an OEM Owner's manual for my '09 Spirit 750.
I do have a good understanding of the different octanes and their correlation to specific engine (design).

Can anyone with an owner's manual or first hand actual knowledge state what Octane is factory recommended for our shadows?
I've typically always ran premium in my bike just in case and never had any apparent issues with it... and being a small tank, a few extra cents doesn't break the bank.

Now if I was filling up my old Jeep... with a 20+ gallon tank... that's a different story.. and fortunately it's old and is recommended to run on 87 all day long.

I always tend to run Shell brand in all of our vehicles.. (bike, Jeep, wife's car). Just because I like the detergent/cleaner package they use over other brands. But these days, whatever isn't costing an arm and a leg plus your first borne. lol.
It's probably 87 octane for your bike.

Go to TECHNICAL DISCUSSION, open up FUELOLOGY.

Running a higher octane does nothing but waste your money. Higher octane fuels do not burn cleaner, provide more power, and they don't burn slower. Octane only increases the fuel's resistance to pre-ignition, like from a hot exhaust valve or piston surface. The tendency to pre-ignite is increased under increased pressure, hence the need for higher octane in a high compression engine.
 

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Discussion Starter · #12 ·
Agreed there Vito... I do know what octane does.... and maybe it's just me...but I've always considered motorcycle engines to be higher compression engines in general as most typically are. that being said.... with the way fuel prices are now.... it's good to know that only 87 is required per the manufacturer in our Shadows.
 
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