fuel

[fairweatherrider]

Would it do any harm using 89 octane fuel? The manual states to use 91 0ctane or better.

[Water Warrior 2]

Me first to respond I hope. Buy the cheapest top tier gas in town. You don't need more than that.

[blaine]

Originally Posted by Water Warrior

Me first to respond I hope. Buy the cheapest top tier gas in town. You don't need more than that.

:plus1:


Any higher octane is a waste of money.

[fairweatherrider]

Thanks for the replies. I figured it was ok but wasn't sure.

[alantf]

The 91 octane is mentioned in my European GZ handbook. I've mentioned this before on the forum, & the general opinion is that 91 octane is the European measuring system, & nothing to do with the American system. 91 octane is, apparently, something quite different in America. Can anyone come in at this point & let us know what 91 is in America, as I forget? :2tup:

[dhgeyer]

BMW uses an octane rating system called "ROZ" in their manual, and its octane numbers are a lot higher than the US rating system for the same fuel. They call for 98 octane in my bike! I just looked at my US GZ250 manual, and it says to use regular unleaded, with a minimum pump octane rating of 87. That's regular gas in most places, although I did notice that in some of the western states regular gas is 85 pump octane.

I don't remember the conversion from European system to US system either, but this I do know: there is absolutely nothing about the GZ250 engine that would require anything other than regular (87 pump octane) gas. That's all we really need to know. I've got a conversion table written down somewhere. If anyone's really curious I'll see if I can find it.

Contrary to much popular belief, there is nothing to be gained by using high octane fuel in an engine designed for regular.

[alantf]

Originally Posted by dhgeyer

there is absolutely nothing about the GZ250 engine that would require anything other than regular (87 pump octane) gas.

Now that you've mentioned 87 octane, something rang a bell, & I do believe that's what was stated before, as the American equivalent of the European 91.

With regard to the 98 octane you mentioned, that's our "super". We get 95 & 98 at the pumps, so I run the GZ on 95.

[Easy Rider]

Originally Posted by fairweatherrider

Would it do any harm using 89 octane fuel? The manual states to use 91 0ctane or better.

What copy of the manual are you looking at, exactly ??

IIRC, the one that is avalilable online here is from a European model and has European octane standards; their system comes up with different numbers for the same gas. Their 91 roughly equates to 87 in North America.

I wonder if the copy here could be corrected.....or noted somehow.
This misunderstanding comes up a LOT it seems.

[fairweatherrider]

Chapter 1 page 3 of the downloaded manual states 91 octane or better. I should have read further as chapter 7 page 32 states 87 octane. My mistake.

[Sarris]

From my previous post:

Originally Posted by Sarris

The European and American octane numbers are different for the same stuff.

America uses the MON + RON/2 to achieve the stated octane number, whereas Europe only uses the RON (?? one or the other) number.

MON is the Motor Octane Number and the RON is the Research Octane Number. One is numerically lower than the other for the same stuff.

SOS, regular is regular is regular is regular.... Use the lowest possible grade available. It will run on 60 octane cat piss if you can find it.