This is sort of a double question. I've been running 87 octane & its been fine, but the weather is getting cooler & I'm having troubles starting on a cooler morning (<70 Fahrenheit). I know very little about mechanics but my mental troubleshooting goes "if it clicks & won't start, battery. if it turns over, fuel". Would running higher octane fuel help it start &/or run better? I have a Clymers & I swear that thing doesn't tell me what fuel to run. It'll tell me how to full dissemble & reassemble the bike, but not what kind of gas to use.
Quote from: samburger on September 17, 2010, 04:12:49 AM
This is sort of a double question. I've been running 87 octane & its been fine, but the weather is getting cooler & I'm having troubles starting on a cooler morning (<70 Fahrenheit). I know very little about mechanics but my mental troubleshooting goes "if it clicks & won't start, battery. if it turns over, fuel". Would running higher octane fuel help it start &/or run better? I have a Clymers & I swear that thing doesn't tell me what fuel to run. It'll tell me how to full dissemble & reassemble the bike, but not what kind of gas to use.
If you have been on this forum for very long, you will recognize that this topic comes up every so often and is one of my major peeves!
Octane rating has nothing to do whatsoever with your squawk of hard starting in cold weather. Higher octane will not make an engine (designed for regular) "run better" or "smoother" or "more powerfully" or ge 'better mileage".
RUN REGULAR IN YOUR ENGINE...........!!!!!
Octane rating is simply a measure of anti-knock ability............if you engine does not have "knock".....on regular.....you're finished.....use regular....end of story. (if a gs 500 does "knock" on regular, it is an engine problem, not a fuel problem, i.e. massive carbon build up on piston, cylinder head, timing off, etc.)
If you have other symptoms, like hard to start, in cold.....look for other problems, like choke/enrichment system, spark plugs, etc.
Cookie
^spot on.
trouble starting in the cold - check spark plugs and battery.
if not those then you have a bigger prob with the engine but if it runs fine when warm then it prob some other maintenance issue
x2
Then why does my '98 say run 91 or higher under the seat on the fender with all the basic bike info? I run shell 93 with all that cleaning shaZam! in it.
Samburger,
You do use Full Choke when starting, right?
As twocool said, Octane is really an Anti-Knock guide. But, that doesn't mean people are not experiencing different performance on their bikes based on which octane fuel they are putting in.
The owners manual says... Use unleaded gasoline with an octane rating of 91 or higher (research method). Research Method is the Method used to come up with an Octane number. Says for Canadians to use a Minimum of 87 ((R+M)/2) - the octane is figured using Motor method, it is added to the Research method number and halved for an Average.
Either way, the Suzuki-supplied manual says to try different octane and even brands cause there are differences between the brands.
I can attest to the difference in Brand - my bike runs better on BP than Shell. And as for Octane, well, with pretty well all 91 (Aust lowest) now containing ethanol, I use 95 as a minimum.
When I spoke to Caltex, I was told the 95 and 98 have Stuff in them to keep Injectors clean. So the Octane number isn't Just about the fuel's ability to not knock. Other stuff is going on we consumers don't really know about.
Best thing... try different brands and octanes in your bike and use what gives You the best results.
Michael
Quote from: kylegod on September 17, 2010, 01:27:17 PM
Then why does my '98 say run 91 or higher under the seat on the fender with all the basic bike info? I run shell 93 with all that cleaning shaZam! in it.
What country are you in? Different countries use different octane calculation methods, thus arrive at different numbers for the same gas.
USA is R+M/2 or the average of two different octane rating methods.............many other countries just use the higher number, not the lower, or the average........just advertising gimmick, to make you think you are getting more for your money.
Running higher than spec octane will do no harm, other than to the wallet.........but will offer absolutely no benefit either!
Do not run lower than the mfgr's spec...........
I don't see why a '98 would require higher octane than my '09, unless they used higher compression back then....
Cookie
Quote from: mister on September 17, 2010, 03:11:46 PM
Samburger,
You do use Full Choke when starting, right?
As twocool said, Octane is really an Anti-Knock guide.
The owners manual says... Use unleaded gasoline with an octane rating of 91 or higher (research method). Research Method is the Method used to come up with an Octane number. Says for Canadians to use a Minimum of 87 ((R+M)/2) - the octane is figured using Motor method, it is added to the Research method number and halved for an Average.
Either way, the Suzuki-supplied manual says to try different octane and even brands cause there are differences between the brands.
I can attest to the difference in Brand - my bike runs better on BP than Shell. And as for Octane, well, with pretty well all 91 (Aust lowest) now containing ethanol, I use 95 as a minimum.
When I spoke to Caltex, I was told the 95 and 98 have Stuff in them to keep Injectors clean. So the Octane number isn't Just about the fuel's ability to not knock. Other stuff is going on we consumers don't really know about.
Best thing... try different brands and octanes in your bike and use what gives You the best results.
Michael
"But, that doesn't mean people are not experiencing different performance on their bikes based on which octane fuel they are putting in."
Well, maybe they "feel" something, or not, but there is no science or research or practical experiment to back that up.
Yes, "bad" gas will make a motor run poorly......"good" gas will make it run to spec..........."better" gas (higher octane or different brand will make no difference..........
Suzuki says to try different brand or octane IF you get knock.......if you don't get knock, a different brand will do no better...just the same .....(or worse)
Yes different brands may put in some different additives, detergents etc........maybe better in the long run for engine cleanliness etc.......but no performance increase, or mileage increase.......Plus it doesn't have to be high octane to have the additives.........
Alcohol in gas is a different story........but as far as octane is concerned, alcohol or not, octane is just anti knock, nothing else
On another forum I made a challenge.....and I will make it here too.........lets get together......10 bikes and 10 riders...........and make a nice long ride over varied terrain and road conditions............
Get gas of various types and octane............switch gas in the bikes but don't tell rider what gas it is..........see if a "blind taste test" will show one gas better or not..........
Then tell rider "this is the good gas"....bet you get false good reports!
Without such a test, its all urban myth!
Human nature.......
Cookie
toocool pretty much has it...all an octane reading is the resistance the fuel has to detonation due to tempurature caused by the compression of the engine...that's why higher performance engines use premium fuel, they run higher compression ratios...I'm not sure why any GS500 engine would require more than 87 octane, since it is not a high compression/performance engine...not sure where Samburger is from, but here in Canada the highest octane rating I have seen at the pump is 93...unless you go to a specialty place...
Quote from: madjak30 on September 18, 2010, 11:07:11 AM
toocool pretty much has it...all an octane reading is the resistance the fuel has to detonation due to tempurature caused by the compression of the engine...that's why higher performance engines use premium fuel, they run higher compression ratios...I'm not sure why any GS500 engine would require more than 87 octane, since it is not a high compression/performance engine...not sure where Samburger is from, but here in Canada the highest octane rating I have seen at the pump is 93...unless you go to a specialty place...
Yep!
Back to original question:
Problem: Hard starting
Solution: Nothing to do with octane...........look elsewhere....
Cookie