Hi everyone, I had my 94' cbr900 for about 4 years now. Every since I purchase it, I've been using 91 octane since. Back then, I really did not give it any thoughts to as what grade previous owner was using. When I pull up to gas station, I just select 91 believing this will keep carbs clean & better performance? Now gas price gone thru the roof, and everything is getting expensive. I have thought about downgrading to 87 or 89? Would there be any risk involve? Bike has 24k, new iranium plugs, seems to be running good...with 91... Is it okay to switch back to 87? And if this matters, I'm not planning to sell this bike anytime in the near future. It's a keeper. Any suggestion is appreciated.

 

Unless the engine compression or timing has been modified from stock use whatever the owner's manual calls for.

 

 

I'd do some experimenting. Try it with 87 for a few gallons.
It might like it.

 

Dude, when your filling up a 5 gal tank it only works out to be 50 cents to a dollar more than filling up with the cheap stuff, just go with premium. I've never used less than 93 in my bike, that's premium around here. These are such specialized engines at an extreme rpm, why risk it?

 

I ran my old 96 RR on 89 the whole time I owned it,no issues.

 

Well said .. Tks!!