Well I have yet to "observe" any yfz with stock compression have any issues related to predetonation or lack of sufficient octane. We are about 500' above sea level here, so the same octane should perform better as altitude increases.

 

Everyone would love to have physical evidence but it is physical evidence the leads to safer calculated estimation. Since you seem to have some pyhsical evidence, what would you recomend the minimum safe octane rating be for various compression ratios in general(assume stock ignition timing and throw all other variable out the window)?

 

If you real the manual or the little sticker by the tank it reads "min 91 octane"

 

 

 

min 91 octane - As in MINIMUM!? lol

 

Yes minimun meaning not less than. If there would be problems with the engine at 91 octane I think Yamaha would put a higher minimum rating. I could be wrong they only desinged the eninge.

 

94 to the pump here!!!! stock bore... runs like a million dollars!!!!!!!!

 

I appreciate the octane lesson. Is there going to be any changes on the 2006? Thanks.

 

lol IDK.. shee or Rappy for Dunes... better than YFZ