Regular, mid-grade or premium?

[HERRBAYEMVAY]

I've always put in premium in all the bikes I've owned in the past, including the '81 R65 I had before purchasing my 2nd R65, a '84 model. (My '81 Beemer always seemed to run fine, too.) The guy I bought the '84 from (who owned it for the past 10 years) said he had only put 87 octane regular in it. I know the specs in the owner's manual specify 87 grade as well, but I was wondering if putting premium in the tank does make the engine perform a bit better, or does it result in fouled plugs or anything else that might lessen the performance. Any thoughts or experience with changing the fuel grade? Thanks! John

 

[kbasa]

I use the minimum octane that will let the bike run without pinging. Anything beyond that isn't useful.

 

[Hawk Hawthorne]

Way to go, Dave. I run 87-89 octane in my 86 R80RT with now problem. In fact, the K75 rarely gets higher than 89!!



Hawk Hawthorne
VP BMW MOA

 

[widebmw]

I use 91 at sea leavel or below, 87 over 3,000 ft.
It all depends on your altitude.

 

[solarbean]

Years ago I I had a '75 R90S with high compression (Luftmeister?) pistons and dual plugs. That baby pinged like hell. I always used the Sunoco 94 octane with that 104 octane boost additive (the stuff in the red can), and it still pinged. Then I drilled/filed the breaker plate to try to get the timing right, and it still pinged. Then I sold it for $1800 and bought an '83 R80RT. I used the same Sunoco 94 octane gas and ne'er a ping.

Man I loved that R80RT... best bike ever made in my opinion.

My current bike is a R100RT. I use whatever high-octane they happen to have. It does not ping. Perhaps I could get away with the lower grade.





OK. Wake up. I'm done.

 

[TC]

The correct answer is ........use the minimum octane that will let the bike run without pinging.
My 90/S runs great on Sunoco high test.....No prablemo