[crazycraven420]

Both 600's btw..

[Wild-Bill]

Interesting. My 1100 doesn't say a thing about octane on the frame label. It runs great on 87 octane as did my '96 750. Maybe it's a 600 thing?

[girlstrytohard]

for $500 there is probably a member here that will sell you a set of carbs that are already rebuilt
And they are rebuilt by somebody that actually knows them

Talk to arsenic. I think he might have a set for $400 on eBay

[Wild-Bill]

He does take trade-ins. It's not much but it helps take some of the sting out of the price.

[crazycraven420]

It's on the left side, at least on the 600's. I never really took much notice until I swapped and it was in my face, just referred to the right side for tire psi etc.

When I first got my bike I had a fresh 5 gal of regular and ran that, followed up with super an been sold ever since
91+ octane and Star-Tron enzyme treatment fuel additive are a must for me at every fill up. This is all based on my high tech, state of the art seat-o-pants dyno of course
Not trying to start a debate, just my choice.

[Aimbot9000]

Actually....I noticed on the neck of the frame on my parts bike when i swapped motors it said 91 octane minimum. So I just took a picture of my 94 stamp on the neck (parts bike is 96) and it also says 91 octane minimum. As far as I know neither of them are Cali models...

that says 91 RON octane minimum in the USA and Canada we use the average of the RON and the MON seen on the pump as (R+M)/2) as the MON is about 8 to 10 points lower than the RON that would give you the 87 octane that is shown on the pump.

[crazycraven420]

" A fuel with a higher octane
rating is less prone to auto-
ignition and can withstand a
greater rise in temperature
during the compression stroke
of an internal combustion
engine without auto-igniting,
thus allowing more power to
be extracted from the Otto-
Cycle.
If during the compression
stroke the air / fuel mix
reaches a temperature greater
than the auto-ignition
temperature of the fuel, the
fuel self or auto-ignites. When
auto-ignition occurs (before
the piston reaches the top of
its travel) the up-rising piston
is then attempting to squeeze
the rapidly expanding
(exploding) fuel charge. This
will usually destroy an engine
quickly if allowed to continue.
In the case of the normally
aspirated engine, at the start
of the compression stroke the
cylinder air / fuel volume is
very low, this translates into a
low starting pressure. As the
piston travels upward, a
compression ratio of 10:1 in a
normally aspirated engine will
most likely not start auto-
ignition. But 11:1 may."

IMO id rather just avoid regular and and run close to 91.

[Wild-Bill]

Like I mentioned earlier, because of the price of the higher octanes, I run the lowest octane that a vehicle will take. If you don't get pre-ignition using 87 then that's what I use. My Kat runs great on 87 octane as did my 750 Kat. My '66 Mustang wants 89 or else it knocks. YMMV

[Kreylyn]

IMO id rather just avoid regular and and run close to 91.

Just FYI... the compression ratio by numbers may seem high, and would be considered high for a lower rpm ranged car/truck engine.

The motorcycle engines are a bit different, and the Katana/oil cooled GSXR engines with out some serious modfications are no where near being considered "high compression" motorcycle engines to warrant anything needed differently than 87 octane rated gas. I mean, not even even close enough that the common mods like jet kit, advancer and aftermarket exhausts would have any affect to cause a need for a higher octane.

There is really only 1 reason you will ever see a "false improvement" of any type by using a higher octane, and that is running a lean setup or clogged carbs causing a lean fuel mixture. This is not a reason to run higher octane instead of fixing the issue. Despite some claims that I've seen, I have yet to hear of someone having that issue... switching short term to higher octane and it "cleaning things out" to make it so they switch back and the bike runs fine. It's almost always that they keep with the higher octane to mask their poorly maintained engine/carbs. What it masks is the ping, but it does not make up for the performance degradation of having an incorrect a/f mix at the various rpms. The proper fix is to clean the carbs, and tune them properly with the correct octane fuel.

That said... minute performance differences aside, if there is nothing wrong with your bike... running 87-91 octane fuels isn't going to "hurt" anything. The bike will run with all of them.

In a perfect setup though, your best performance and fuel by design for the engine setup is 87.

There is no more energy or "power" in comparison to any of those 3 fuel choices, so switching is not going to "make it better" power wise... unless we are back to something is wrong and your bike needs fixed.

The choices for fuels with no ethanol vs ethanol blends some times plays a part, as some companies claim that their "premium" blends contain no ethanol. If that is what your going for then I would say that isn't about octane at all really... just a side effect of wanting no ethanol.

Locally here I can find stations that sell all 3 options ethanol free so if that is also an option for you, then again your gain nothing by using higher octain.

Finally I hear people discuss the "additives" or "cleaners" added to "premium" fuels vs lower octane fuels... My research has shown that when comparing specific company fuel sources, those additives are the same and in all 3. They just focus their advertisement on the "premium" to further perpetuate the erroneous concept that "higher octane" = better because you pay more for that and thus = higher profits for them.

This isn't an argument I'm trying to make to change your mind. I don't care what you run in your bike. I do think that if you take this information as suspect, and then research and verify it yourself... you are highly likely to come to the same conclusions... and maybe even question your prior choice to use the higher octane. Or... you may verify your choice for other reasons; such as the ethanol concerns.

Krey

[crazycraven420]

It's all very logical as you've pointed out. I have had a friend do an ethanol test in a few different gas stations I use and found I can get down to about 8% ethanol as compared to 10%. Not really a large enough reason to warrant paying more IMO.
Mostly I use it for how much smoother she runs. Again, not a huge difference enough for me to notice. This very well may be my carb setup, unfortunately I can't get a sync right now cuz I have a broken vacuum port on carb #2 or 3. Hopefully as soon as I can get damn taxes done I'll be getting a new set from Arsenic . Than I will re evaluate my choice of fuel and go from there. Thanks for the input

Though the only thing.I do question is since I use an additive (star-tron) to combat the ethanol does that lower the octane by neutralizing the ethanol? Therefore validating a use of higher octane?

[Kreylyn]

Though the only thing.I do question is since I use an additive (star-tron) to combat the ethanol does that lower the octane by neutralizing the ethanol? Therefore validating a use of higher octane?

No, doesn't work that way. Star Bright claims that the octane is maintained with their additive by preventing the phase seperation that occurs when water is introduced to ethanol blends (from atmosphere or liguid form). In other words, it doesn't neutralize the ethanol, it keeps the ethanol from breaking down.

See more there... http://www.starbrite.com/whatsnew/ST...%20p3072D2.pdf

Krey

[crazycraven420]

Ahh, very cool. thanks!