[blitz2190]

any professional tuner will tell you if you advance your timing or increase compression(or both) you will need to increase octane. It more so causes the burn to be more consistent instead of lighting gas infront of the main flash(pre detination) than "slow it down".

[Kreylyn]

any professional tuner will tell you if you advance your timing or increase compression(or both) you will need to increase octane. It more so causes the burn to be more consistent instead of lighting gas infront of the main flash(pre detination) than "slow it down".

If you were advancing the ignition past the OEM designed for use with 87 octane fuel, they would be right.

US model bikes have their timing retarded... Pretty much all other country models do not.

Putting one of these advancers on a US model makes It = non US model timing.

Putting an advancer on a non US model... changes nothing.

87 equiv fuel is recommended by Suzuki for ALL country models.

Krey

[blitz2190]

Putting one of these advancers on a US model makes It = non US model timing.

87 equiv fuel is recommended by Suzuki for ALL country models.

These I did not know, always teaching

[crazycraven420]

look on the neck of your frame below your handle bars, on the right side is the vin etc...on the left is a plate that should say 91 RON which translates to 87 octane at the pump.

[ZukiFred]

My Kat loves the cheap stuff.

[Jreid843]

Guess im now about to be saving 30 cents a gallon

[Mopar-Man]

Any benefits from running advanced timing and higher octane fuel are reduced or even negated as you approach the redline - hence a poor result on a dyno if all you are measuring is max HP. The benefits are most noticeable in the lower half of the RPM range (touring rather than sports) when the timing advance will have a greater influence on the whole fuel ignition process, as will a higher octane fuel's role in slowing the explosive effect of combustion and preventing pre-detonation ... which you tend to get at low speed and under load. (The standard Kat 5* advancer is a huge advance in an otherwise non-modified engine.) Ambient temperature, altitude, humidity ... also play a role.

If your style is to bounce the needle off the redline, you will probably see little benefit from an advancer or premium fuel (unless premium = no ethanol). If you tend to spend most time in the low-mid range in 100*F temps, you may very well see benefits.

Exactly. Higher octane fuel will allow you to run more timing and increase bottom end TORQUE which on a heavy bike like the Kat, makes a world of difference. Too much timing will hurt peak horsepower.

[arsenic]

You know what running higher octane on a Katana gains you? NOTHING

[crazycraven420]

You know what running higher octane on a Katana gains you? NOTHING

[numus]

So what does Octane mean? Give you a hint, in the US we use "AKI"...

[Stumpy]

I don't think it really matters on Kats. Our lumps are ancient relics of technology that don't need high performance fuels. Just fill up and go!

It matters in a petrochemical lab or a Ferrari, not on a 80's motor

[suzuki99]

I use to run 91 octane but then I started using 87 and it runs just fine! Plus, I am saving money at every fill up!

[TRPUT]

You know what running higher octane on a Katana gains you? NOTHING

I guess you're right as always ... well, nearly always. Must be only the GSXF that benefits from premium fuel - especially one with the timing advanced 9* over US spec, a K&N air filter (they suck too!), slip-on, and carbs tuned with an O2 meter so turns and clip positions aren't just general approximations. All the premium fuel did was allow me to advance the timing further and still eliminate the knocking on hot days, smooth out power delivery and noticeably improve torque especially in the low to mid RPMs, keep the carbs spotless and return damn near 60 MPG. I'm a slow learner so I guess I'll just keep doing it all wrong and wasting my money.

Of course:

1) If you have done nothing else to the bike (eg timing advance and mixture - 2.5 turns had me way rich) there will be little to no benefit in high octane fuel.

2) Australian fuels are better than the soup you run in the US.

[Ronny]

Just out of interest, does anybody find that a different fuel supplier gives different results? I find supermarket fuel to be pretty crap compared to the really big fuel companies' products. The smaller fuel retailers are a mixed bag, some good and some not so good.

That said, I'm not convinced there's any advantage in using higher octane fuel, so few people seem to buy it that it must be half degraded by the time somebody wants a drop!

[arsenic]

There's always gonna be at least one numbnutz that swears higher octane in his ancient Katana makes a difference. Rock out with your bad self good sir.