BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Samiam

I for one will not excoriate you, as I have always chosen to address theory and practice. Once again, there are many variables, the blend, the region; differences between bikes, state of tune, one or the combination of many can affect the operation of the engine.

Likewise, I have always advocated to each it's own....what works for you might not work for the next person.

def38 statement is quite true,

Our boxers run on the ragged edge of stoichometry. Reduced fuel octane can cause severe engine damage.

.....in the case of the oilheads, it ranks right up there with, clutch spline failures, fuel QD's failure, wire bundles overtightened by nylon ties and of course the dreaded "surging"

I run 89 in cooler weather and 91 in the summer.
Pings too much in the summer if I don't.

toolinalong wrote:def38 asks "So, what is your point? What should we use for fuel? Which grade (octane)?"

My answer is everyone must investigate the issue as much as they feel like and then make up their own minds, like we always do; you have, so have I, and we are not exactly very far apart in our opinions. I will buy the octane rating that the manual calls for, just like I've been doing. I just did not know that I was doing it before today's research told me what the real effect of altitude is. And the cost of doing so is insignificant even at 20 cents more per gallon.

Excellent...yes, do your own research and make your own decision. But, for those who want an answer, my opinion is to stick to the BMW fuel recommendations.

Your situation at the high altitudes leaves you with considerable latitude regarding anti-knock requirements. Until recently, I rode at sea-level in Houston where anti-knock requirements as well as heat required careful fuel selection so as to avoid detonation.