Yea the previous owner on my bike said he was running premium the whole time, so I did it a couple times then read here and in the manual you should run 87. I've run 87, 89, and 93, so far I get the best mileage w/ 89.

 

If you run higher octane too long you'll build up carbon deposits. These create hot spots which lead to detonation. To counter that you need higher octane gas. So using to high of an octane eventually makes you need that high octane gas. But you'll never get the combustion efficancy of 87 octane in a non carbon fouled motor.

 

I know you've said this several times, but the previous owner on my bike claims to have run premium since he got it. I got it at about 16k miles on the odometer. So it should be running like crap if what you say is true. Do you have any links/articles to back up what you're saying?

 

I don't need articles to back it up, its common knowlage in the internal combustion community. 16,000 miles is hardly enough mileage to build up the kind of carbon deposits needed to create problems unless the motor has been also running very poorly from something else the entire time. Again, the engine won't run like crap with high octane gas, even with carbon deposits creating hotspots. The high octane will prevent the detonation. It just won't run as well as a clean motor running 87 octane [think a couple horsepower and a couple MPG's]. And this 87 octane rule applys to F4i's, not every bike. Some bikes need 91 octane. They will tolerate less but will pull timing to keep from detonating and damaging the motor which kills power and mileage.

 

I've searched for info on this several times now and all I see is hearsay from people like yourself posting on forums. When searching for causes of carbon deposits not once have I found anything indicating that running higher than the spec'd octane gas as the cause. Obviously from a cost standpoint run the lowest octane you can get away with w/o detonation and pre ignition, but I don't believe pump gas w/ a little higher octane rating is gonna cause the effects you mention at any mileage on a properly maintained vehicle. That being said, I don't think either of us will convince each other that their view is the correct one, so I'll just leave it at that.

 

The carbon build up thing is pretty much irrelevant. The slower burning higher octane fuels are obviously not getting fully combusted so logic says thatd lead to carbon build up but ive never seen anything showing that just a few years of running 93 vs 87 will cause any significant build up or cause any significant power/efficiency losses but over a decent amount of time then im sure. The main thing is just that people put premium in bikes that are meant to run 87 and they think its better when in reality it does nothing except cost more and potentially decrease power and gas mileage IN THE LONG RUN and theyre just ignorant for still refusing to believe otherwise. Agreeable?

 

I think that's true for some people yes. I run maintenance doses of marvel mystery oil in my gas as an upper cylinder lube, cleaner, and stabilizer. That is the main reason I run 89, b/c I'm diluting the gas w/ an additive.

 

Like bored said. Run 87. If your bike calls for 91, run 91 (which in this case it doesn't). A lot of bikes with a bit higher comp ratio ask for 91.

If you tune your bike on the dyno, continue to use whatever you tuned with. Racers will usually bump up the octane to play it safe because they are running the motors extremely hard, back to back and often times in hot climates. All that extra heat could possibly lead to det./knock. Not to mention they might run a thinner head gasket or something as well, but usually when you get that serious you start using race fuels for consistency (gas companies play with fuel to match the temp/weather changes).

Run 87. I use it in sofla and have never heard a ping or a knock. I think if anything it's more important to buy your gas from a decent company. I did read somewhere that some companies pull more of the residue or waxes or something out of the 93 and put it in the 87 but not sure if it's true. Another thing to consider is that 87 gets used more so could possibly be fresher.

 

So my 96 F3 requires 87? I've been putting 91 in it for the past two months, oops. 87 it is. Can someone please post a link to a F3 owners manual stating 87 octane or snap a pic in one of theirs of the statement? Thanks.

 

I don't have a link to your owner's manual but google might help you find one. I found this searching in the F3 section, read post #14https://cbrforum.com/forum/cbr-600f3...-129845/page2/.

EDIT:
LilRed F3 I found a link to your manual http://www.stephygee.com/F3manual.zip.