Gas grades

[rkj2002]

Hi Guys, I'm running two bikes on the street, a 1985 GS700e and a 1985 Nighthawk 650sc. Both have 9.5 to 1 compression and both seem to run better (and gets better mileage) with the better fuel.

I'd be interested in what you guys think about this and what you use in your machines no matter what you ride (please tell me what bike you're speaking about though).

Thanks, Rick

 

[JEEPRUSTY]

Burn the fuel specified in the manual. As long as its not knocking then all is well. Burning a higher grade fuel is a waste of money.
I think all our bikes specify unleaded or low lead regular gas.

 

[Nessism]

Found these in the archives using the search feature...

http://www.thegsresources.com/_forum/showthread.php?t=171846

http://www.thegsresources.com/_forum/showthread.php?t=169369

 

[Hammered]

My 83 GS650 ran sweet with very good gas milage on 87 octane before I went deer hunting with it. Course I ran a couple caps full of Seafoam every third or so fill-up.

 

[Steve]

All the machines in my sig and all my cages get only the finest, cheapest gas I can scrounge up.

No gas-related failures, EVER.

.

 

[don]

I've always used the cheapest grade. My 550 gets 50+ miles per gallon and my 1100 gets 40+ miles per gallon. Both pull consistant and smooth all the way through the throttle range.

The only time either of them will ping is riding 2-up going up a steep hill in too high of gear,(2000-3000 rpm or less), when it's hot out.

 

[Baatfam]

Burn the fuel specified in the manual. As long as its not knocking then all is well. Burning a higher grade fuel is a waste of money.

This!

My GS1100E gets regular...
The BMW requires premium...
The Triumph requires 89 octane minimum...

 

[cableguy]

I believe only your higher compression motors actually NEED high octane gas because lower octane gas will detonate under compression before the top of the stroke, which is the dreaded ping. That's probably why hot engines under load would ping too (a few replies up). I'm not sure, but I think anything under 11:1 is good to go on regular. I could research of course, but I'm too lazy at the moment. Someone will post a correction I'm sure.

 

[sk843143]

its not the static compression ratio that you have to worry about..... depending on the valve timing events even 10:1 could be to much for low octaine. in some cases the high grade stuff could actuly make the engine run worse>>>> given those cases are rare though

 

[Jason the terminator]

Factory service manual states to use premium in my 1100E. I have tried all three grades and it runs the best and gets the best mileage on premium.

 

[cableguy]

Premium almost always has the good cleaner additives, which might account for smooth running and high mpg's.

 

[rkj2002]

All I know is what the mileage figures turn up and how my 700e runs; seems to like the expensive stuff, and that's actual, not dreamed up or subjective.

You hear alot of stuff about how bad gas is these days, for an extra buck or so a tank seems like l can give her what she wants~

Ride safe, Rick

 

[1_v8_merc]

gs650 manual says 87, I run 87!!!

My camaro says atleast 92, I run 93!!!

-----
Premium fuel is a waste unless you have higher compression, supercharger, turbo, nitrous,etc....


There ARE some people on here that run Premium on ther fairly stock GS'es which CALL for Regular. Most of them state that their GS Pings or knocks a lot unless they use Premium.
(I'm not going to argue, because I guess everyones bikes are slightly different even if they are the same make/model....after all they are 20+ years old)


But it STILL amazes me how many people think that Premium Fuel is cleaner or Contains additives and things of this such nature........

What amazes me MORE, is the amount of people that think OUR bikes all require Premium! As I recall, premium wasn't that common back then, not too many cars or bikes required it.

A lot of stuff was just made to run on regular pump gas.

 

[rkj2002]

gs650 manual says 87, I run 87!!!

My camaro says atleast 92, I run 93!!!

-----
Premium fuel is a waste unless you have higher compression, supercharger, turbo, nitrous,etc....


There ARE some people on here that run Premium on ther fairly stock GS'es which CALL for Regular. Most of them state that their GS Pings or knocks a lot unless they use Premium.
(I'm not going to argue, because I guess everyones bikes are slightly different even if they are the same make/model....after all they are 20+ years old)


But it STILL amazes me how many people think that Premium Fuel is cleaner or Contains additives and things of this such nature........

What amazes me MORE, is the amount of people that think OUR bikes all require Premium! As I recall, premium wasn't that common back then, not too many cars or bikes required it.

A lot of stuff was just made to run on regular pump gas.

Premium fuel has been around since I pumped gas in the early 60's and as I remember our boats took a good grade fuel (marine gas) in our outboards. My nighthawk seems to tolerate regular gas okay but is happier with better grades but the GS really hates regular and runs like crap. That's all I can say about it... It might be that older motors that have a certain amount of carbon build up like the better grades of fuel.

Live free and ride, Rick

 

[Nessism]

My nighthawk seems to tolerate regular gas okay but is happier with better grades but the GS really hates regular and runs like crap. That's all I can say about it... It might be that older motors that have a certain amount of carbon build up like the better grades of fuel.

Live free and ride, Rick

Something is wrong with your bike.

 

[salty_monk]

I agree, 3 different GS bikes and none are any different on any grade of gas.
If you have huge carbon build up raising compression that could explain it...,

 

[DanTheMan]

87 octane. Out west I run 85 octane (lowest grade) except in the higher elevations and low desert with temps over 100 deg F because then it tends to ping. If I hear pinging (pre-detonation), it's time go up one grade.

 

[chuckycheese]

Reg

Reg

Factory service manual states to use premium in my 1100E. .

Mine doesn't!

 

[David_510]

On my 83 gs550esd i've tested this theory actually...
Done it in my car and truck aswell..

On 87, 3.8 gallons of gas will get me 172~ miles

On 89, 3.7 gallons of gas gets me 188~ miles

On 91 3.8 gallons of gas gets me 214~ miles

So as you can see, my bike runs better on premium. It's not like there is a difference in the type of additives, it's the extra added octane.

This is the same for my car aswell (a 240sx 2jz motor) where i get about 8 mpg better (24mpg) running 91 over 87.

And same goes for my truck (03 dodge hemi) gets about 2 miles better off of 91 (13 mpg WHOOHOO!!)

 

[Nessism]

On my 83 gs550esd i've tested this theory actually...
Done it in my car and truck aswell..

On 87, 3.8 gallons of gas will get me 172~ miles

On 89, 3.7 gallons of gas gets me 188~ miles

On 91 3.8 gallons of gas gets me 214~ miles

So as you can see, my bike runs better on premium. It's not like there is a difference in the type of additives, it's the extra added octane.

This is the same for my car aswell (a 240sx 2jz motor) where i get about 8 mpg better (24mpg) running 91 over 87.

And same goes for my truck (03 dodge hemi) gets about 2 miles better off of 91 (13 mpg WHOOHOO!!)

I don't mean to sound argumentative but this information goes against logic.

Higher octane gasoline actually tends to burns slower, thus it resists detonation better. It does not have more energy per unit volume.

Engine designers can take advantage of higher octane fuels ability to resist detonation by increasing the engines compression ratio, or advance the ignition, both of which will extract more power out of the fuel and increase mpg. Modern engines typically have detonation sensors (called knock sensors) and automatically adjust the ignition timing to take advantage of high octane fuel. Some car manufacturers list two hp ratings for their engines: normal rating using regular fuel, and a high performance rating when using premium.

So if we run premium fuel in our GS without advancing the ignition timing (or the compression ratio) it's not logically possible to get more mpg from our engines. It could be that the particular brand of premium fuel you are using is has less alcohol than in the regular fuel, in which case your story would make since since alcohol is known to reduce mpg. I don't know but the octane alone can not do what you say.