I've been using premium in my 97 GS ever since I bought her (I have a feeling the member who paid 1400 at 31k got taken a little) I paid 1800 for my 97 with 7500 in "virtually" perfect working condition.  Anyway back to my real question....I read in a forum that regular is actually "better" for this bike, is this true?  Should I stop putting premium in?  And since I have been using premium will this "upset the engine at all if I switch cold turkey?

Don't change fuels because someone told you to do it.  On a naturally aspirated engine, you run what works.  If you run regular and the motor doesn't ping/knock, then keep running regular.  If it does ping/knock, step up a grade.

funny you should mention the "ping/knock"...when my bike is still "cold" and not on every ride either, I do hear a "knocking" sound.  Once I've been riding for a half hour or more "if" it was making that sound it totally disappears but it's still a fairly consistent thing when the bike is cold.....and I agree I would not change gas types "b/c someone told me to" I just wanted some enlightenment on the options available .  Thanks!  Any other comments and suggestions are welcome!

octane is a measure of resistance to detonation. The higher the octane, the more resistant. Gas can ignite by compression as well as spark. In a high compression engine, like those of higher end bikes and cages, premium is necessary because lower octane fuels would detonate from the compression before the spark plug set it off. In old engines, with lots of carbon build up, the compression can increase because of that build up, setting off gas too early, causing a knock/ping.

So, unless you have a high compression engine, premium is just a waste of your money. To take care of knocking and pinging, try a fuel system cleaner. Switching between gases doesn't do a thing to a normal engine, it's all the same to something that requires only 87 octane.

that nock you hear is not fuel related.


the GS500 does not require prem fuel, i cant not understand why so many think that prem is better.

it burns slower than regular fuel. which in the gs case the fuel doesn't burn all the way before it get to the bottome of the power stroke (in most cases). if the compression was higher or had a turbo/super charger then yea the added air/fuel would raise the ratio of when the fuel would ixnite and burn.

reg fuel would burn before the plug fired in this case and you would need prem fuel.


google this stuff for more info, but its your money you spend it the way you want.

your knocking = normal for the GS... do a search for "cam shaft free play".. they all knock. If your engine was knocking from premature detonation, you'd know it. Run regular. Save the money. Octane = resistance to detonation. High octane is only necessary in very high compression engines, where the fuel ignites before the spark plug ignites it. The GS is NOT a high compression engine. Therefore, run the lowest octane you can before it knocks/pings. Which is regular cheapo gas. Some people swear they get a performance boost out of premium (my stepmom)... I'm too tired of arguing over it, so I just tell people the facts, let them believe what they want. YMMV

Thanks for all the advice everyone....on my next fill up I'll put in regular for a change and to see if I notice anything different at all, thanks again!

I could swear regular fuel (92 in europe) gets my bike more torque, than premium  . But ofc that could be all in my mind. Sometimes one can be ashamed to put regular in his GS "beast", especialy if a sexy girl next to him fills her sports car with premium and looks at him. Not that i feel so .

+1 on regular fuel. Put premium if it makes you feel better, nothing more.

O3

adn for the "self ignition" that can cause damage cause you get an explosion before you want it then an other by the spark plug and with time it really does damage an engine...

So the GS has 9:1 compression which i know is normal or low. and 13:1 is def a high compression. But where is the line between the two? 11:1 is high? 10:1 is norm?

While I didnt get a fantastic deal considering the small # of 500cc bikes ive seen on craigslist (and this was the first gs500e id seen for MONTHS), and that this is socal after all, its not so bad  Can still sell it for the same price i have little doubt.
carry on.

I put premium in. Never had any problems with regular, but hey, its' 3.29 x 4.0 = 13.16 for about 200 miles or so for premium. Pbhhhhttt...

SOOoOooOOO much money (keep in mind my cager is a 79 Buick with the V8)

Fuel designations like "regular", "super" and "premium" are one of the greatest marketing gimmicks that I have ever seen.  93 isn't any cleaner, hotter burning, higher energy, or in any other way generally superior to 87 octane.  It simply has a different ratio of branched-to-linear alkanes in it which modulate detonation resistance, but by calling it "high-test" or "super" they have convinced millions of drivers to empty their pockets of an extra $0.10/gallon at the pump.

Many cars and bikes (especially the very high performance ones) REALLY like that extra Octane.

It has to do with resistance to early detonation.

Low compression like the GS doesn't need that extra resistance. But higher compression engines (and applications using forced induction) require that resistance. Still I use premium, why? Because it's 50 - 70 MPG WHO CARES.

Let's not start on Centane (diesel measurements) while we're here ok.