if the manual says something, dont go against it.

i hate how everyone becomes an engineer or scientist without creditantials. these hearsay things are what hurt your prolonged useage of a motor in the final result. also, most articles written on octane rating are based on stop and go vehicles on the street. there are other things that can cause detonation besides compression like piston and combustion chamber shape/design, rpm/heat/riding conditions, fuel delivery, etc....

you trust honda to make the bike, they should know what to put in it.

 

The manual also says to break it in easy and to change the oil after 20 hours. I'll do neither of those. Break it in hard and change the oil after the first 5 hours or so is my idea. Just because the manual says it doesn't mean it's correct, that's why I asked for opinions and experiences. Thanks for all the input so far.........

 

i like to trust those little nerds that designed the motor then the internet as a reputable source.

why not just get it over with and put methonal in it? [img]i/expressions/face-icon-small-smile.gif[/img]

 

HA2,
I hope you were not referring to me as the engineer or scientist. I am not, and make no claim to be.
I was simply stating the fact to reconranger, that higher octane is not better if you don't need it, and mixing gas is not good either. I referenced a VERY WELL known and respected MOTORCYCLE engine tuner/builder/and former Factory engine (Yamaha) R&D man.



I run 100 in my 13.5:1 (static) 500R, and its just great. But, then again who am I to know, I am no scientist or expert......Even though I have used EGT and AFR meters, have pulled the head after usage, and have cut many $15 spark plugs apart to see the base of the insulator.

 

not you KGB. i know you're the only one to stated an article, but im not disputing mixing fuels or the benefits of highier octane.


im saying to dispute the manual is to dispute engineers.

even you said that above..."Are you a petrochemist?.."

 

HA2. Crystal Clear..Thanks....
I agree with you.

 

yes, manual does say 91.

i was up for 2 days- my brain said 91, my hands typed 87... like a typo has never happened to
ANY of YOU before. lol

 

12.5-1 is about the max compression on 91 octane. If you are higher in elevation you are easily safe w/ 91 at 3000ft or higher.. You lose one point of compression for every 3000ft in elevation...

 

another thing with octane ratings: if the pump says 91 octane, that's the minimum rating. so running pump 91 octane when the manual says 92 or higher, won't make any noticable difference. i agree with HA2 on following the manual (except that i tend to need an oil change in my 450r after about 60-70 hours, not 100) but using gas that has a minumum requirement of 1 octane below reccomended won't hurt.

 

In the "Quick Reference" section of my owners manual, it says 86 octane or higher. (Right away I figured something was wrong here!) Page 83 says 91 octane or higher, and pg. 184 says 91 or higher. So, I think it is safe to assume that the 86 is a mistake!

As for "mixing fuels", I run a 1:5 mix of VP C12 Race Gas with 91 octane pump gas. (Most people run a 1:2 mix.) My oldest bike where I run this mix is a 99, 400EX that has hundreds of hours of hard a$$ desert miles on the original engine. And the Z400 is starting its 3rd season in the desert, on the original engine. Sorry KGB, but NOBODY I know has been left "..........sitting alongside the trail with a holed piston, bent rod, broken valves, snapped cam chain, or ventilated crankcases threw (through) a hole that wasn't there when you bought the thing............"

Another issue, is that gas is going to lose octane rating during storage. If you started at 91, a few weeks later that gas in your gas can, will probably now be 87.