[cintidude04]

If his buddies all ride rr type bikes, they are right. any supersport bike now a days must use AT LEAST 90 octane. I throw 91 or 93 octane in my ZX14 and CBR1100xx. Anything less could cause engine damage.

Nope.

So wrong, on so many levels...

Yep.

The factory manual for my 2005 GSXR 750 says to use 87 octane.
Only reason to bump up the octane would be for a different compression, forced induction, or altering the timing maps.

[TRPUT]

The machinery manual usually lists the MINIMUM acceptable octane rating. ie DO NOT USE LESS THAN ... In the case of the Kat, it is 87 (or 91RON) minimum. Just saying.

[il_ragazzo]

We should send this to myth-busters, to see if they can send the truth to all over the nation using infallible scientific method broadcasted via the main stream media by pop culture's most respected source for scientific data. I am willing to bet that this argument can be found on ANY gear head forum.

[TRPUT]

I am willing to bet that this argument can be found on ANY gear head forum.

Including this one ... several times over.

[boomer_95]

argument about what? the fact that ethanol is crap? or the "minimum rating" that manufactures put on the bikes? or the ratings themselves?

i covered two of them already. as for the minimum ratings its probably best to just follow them so you don't screw yourself over if/when you blow the bike up and try and get warranty for detonating a high power engine.. they put them there for a reason. either they really need the higher ratings or they haven't tested with lower and they want top cover there arses

as far as i can see theres no argument to be made

[STULER]

Many, many things other than compression ratio and timing determine fuel requirements. Valve size, valve overlap, spark plug type, placement and depth, burn pattern, etc. Basing fuel requirement purely on compression ratio or timing is rather silly.

FYI, Corvette's is due mostly to timing. We run 34+ degrees advance on our Chump car with a 350 in it. Kats run 10 degrees timing, for comparison.

That is my point. What I was saying is that compression is just a small chunk of the whole pie so to speak.

OK back to the original question....... the higher ratings of fuel (I'll use all ratings without ethanol. 87 included. again NO ETHANOL) there is only ONE difference between them. and the one and only difference is to stop detonation in engines. the rating refers to the MON/RON rating of octane. the higher the rating the better at stopping detonation it is. yes different places have different "additives" to help the fuel systems but that aside....

now lower grade fuels usually have ethanol (i don't think there is a place around that doesn't have it in 87) were as higher grades don't tend to have it. mid grades can be a mix of the two (so maybe half the ethanol of regular) or completely without depending on the station

ethanol breaks down VERY quick and is a weaker burn than regular gasoline so there is some performance in higher grades when your talking about with and without it. it also holds on to water..

small engine manuals usually say to run a little higher rating in them but that's only because they know the engine isn't being used 24/7 like automotive and ethanol breaks down ALOT faster than non ethanol.. high performance engines are a different question . with regards to the extreme timing of the spark and valves and the usually very high compression. but the principle is the same regardless. they need the higher octane to stop the earlier detonation that they will produce. i went to school for this and am a technician.. I'm not some random guy on the Internet saying bla bla bla. (well i guess technically i am lol)

What I like about where I live, is that there is a gas station on every corner down the road that has pure 100% gasoline. No ethanol. One gas station is a Road Ranger and it has 100% 87 octane with no additives. One is a Citgo, the middle grade gas is 100%, no additives. and the Shell across the street from that only has 100% pure 93 octane, no additives. I gas up and different places, but try to always gas up with just pure gas w/o additives.

Nope.

Yep.

The factory manual for my 2005 GSXR 750 says to use 87 octane.
Only reason to bump up the octane would be for a different compression, forced induction, or altering the timing maps.

and noticed i had said before, for big cc bikes. the 600's and 750's still use lower octane

[cintidude04]

and noticed i had said before, for big cc bikes. the 600's and 750's still use lower octane

And notice what I said before.

Only reason to bump up the octane would be for a different compression, forced induction, or altering the timing maps.

One of my local riding buddies rides a ZX14, and my old boss has a Busa, neither of them had any complaints running 87 daily.

[boomer_95]

the guy i work with has a newer ZX12R and can put 87 in it.. hell if he has to drain the slightly old gas out of a customers vehicle he puts it in is bike (well not anymore after the last bit of green stinky cr*p he put in, made it run like total cr*p!) he usually uses 91 tho simply because he doesn't use it very much so the lack of ethanol in the 91 will last probably a good month or more longer without stabilizer

i would like to see pictures of these "minimum ratings" on the big bikes you keep claiming.. i only have experience with a few larger CC bikes, so i'm really not sure on that part

again i will say: if it has a "minimum rating" FOLLOW IT! you can go higher BUT NOT LOWER! some of the higher end shops like to send away fuel and oil samples to b tested so they don't get screwed when doing warranty. that and if you are not under warranty anymore the catastrophic engine damage that detonation can cause is a little bit of change out of the proverbial piggy bank

[STULER]

And notice what I said before.


One of my local riding buddies rides a ZX14, and my old boss has a Busa, neither of them had any complaints running 87 daily.

Well then I guess Kawasaki is just trying to rip me off buy specifically writing in the owners manual, use ONLY 90 or greater octane. I guess they really wanna stick it to me and make me spend an extra $10 a year on gas. Damn them!