ST4s octane

What octane is required for a 2002 ST4s?

I was told 87, and that's all I've used.

Thanks Paul ! Do you have an ST4 or ST4s?

What's the owners manual say?

Stick, I have no idea! If I had an owners manual I wouldn't be wasting anyone's time.

ST4s

Thanks Paul! I was hoping that it would run on regular. I have a ST4S engine that I'm planning on putting in my 851.

Here you Marvin:

http://www.ducati.com/my2002/d...=ST4S

http://www.ducati.com/doc/manu...3.pdf

Cool project. Total sleeper

infoage1, Thanks, I did finally manage to download and make a copy, I'm on dial-up! I had forgotten that that info. was on the net.!! I'm still back in the 90's with my 851!!
Marvin

regardless of what the manual says (usually recommends high-test for the higher compression 4v motors), run the lowest octane you can without knocking/pinging. 89's definately ok. 87's likely depending on the environment. if you ride in REALLY hot conditions, 87 may be too low.

Well my owners manual for the ST3 tells me 95 octane? Where in the hell do they sell 95 octane?? I use 93, most of the time, but some of the place I tour only sell 87 and 89, bike doesn't seem to mind the lower octane.

I think they are using the European method , which I believe translates out to be about 87 octane US

[Gilbert]

Originally Posted by Guest

Well my owners manual for the ST3 tells me 95 octane? Where in the hell do they sell 95 octane?? I use 93, most of the time, but some of the place I tour only sell 87 and 89, bike doesn't seem to mind the lower octane.

The 95 octane rating that your manual tells you to use is based on a completely different gasoline mixture & octane rating method, refered to as RON or Research Octane Number. To more accurately specify what your bike should use, the manual should state 95 Octane (RON). RON is used throughout most of Europe, if not all of Europe.

Here in the US, it's different method, based on a combination of RON and MON (Motor Octane Number), refered to as R+M/2. I can not tell you the specific differences, other that the mixtures are not identical, but I can tell you that 95 RON is approximately equivalent to our 89 Octane (slightly less actually). Do your reseach and you will see that here in the States we use the R+M/2 method. Some Chem-E's call it R-(F1)/2. GO FIGURE.

What's best for your bike, car, plane, lawn mower, etc. etc......well, it's the lowest octane number you can get away with, and not experience detonation or ENGINE KNOCK. Why, because the lower the octane number, the more volatile, or readily ignitable the gasoline mixture. Which is what the guy 2 posts above was trying to tell you. Also, a lower octane number also translates to lower combustion temperatures, and therefore less thermal torture on engines internals.