After reading peoples issues with their 07 yz450f's I looked into the issue buy leafing through my service manual that came with the purchase of my 09 yz450f and noted that the bike needs 95+ octane in it's fuel. I'm on the east coast on Canada and the highest I can get is 91 octane. Meaning I'm going to have to look at mixing octane boost with my fuel. If anyone knows the proper mixture and if this could be the problem let me know. Also on my previous post about oil Yamalube was suggested but what rating???? 10w-30 or 20w-50??? whats most of you running in your machines???:bangdesk

mine knocked at 100 octane.It was not an octane related knock - Im surprised the manual says 95 , but would have thought 91+.

dont fret the talk of the knock its not a ping it is just the mechanical noise Yamahas are prone to . probably due to the way the engines are built the compact size and proximity of exhaust and airbox.
wait til you hear the 2010 you will shit a brick it is loud as hell .

IMO do not mix any octane booster either mix a race gas with pump gas or consult your Yamaha dealer incase you are somehow misunderstanding the wording of the manual.

on the oil:
yeah the only yamalube I can get around here is 20/50 and that is what I run in all the yamaha's I own

If I remember correctly the manual gives you a huge range of viscosity possibilities based on riding conditions temps etc.

mixing 50/50 with race fuel or avgas will get you to that octane. You can likely get 101LL at your local airport that'll do the trick.

turns out that the 95 octane rating was "research" rating meaning that at the pump 91 is suffice...I won't get into the details due to the confusion it might lead to....there is different meanings and rating of fuel which involve octane....if your interested to know more by all means head to wikipedia and other web sites to read up on it....:humpleg

turns out that the 95 octane rating was "research" rating meaning that at the pump 91 is suffice...I won't get into the details due to the confusion it might lead to....there is different meanings and rating of fuel which involve octane....if your interested to know more by all means head to wikipedia and other web sites to read up on it....:humpleg

that is what I was thinking it was . glad you figured it out :thumbup

was the bike originally a euro spec model? the North American ones generally have the req octane listed as the average value.

On the west coast Phillips 66-Conoco 76 sells racing 100 octane but its 7 bucks + a gallon. Stick with 91.