Ok, since I read the recent post on octane I figured I would experiment a little myself. And I am quite suprised. I always run 93 octane in my bike (calls for 91) and 91 isnt available here, and have run 93 in it since I got it. Today I filled up my tank with 3.5 gallons of 89 octane (which means it has approx 1.5 gallons of 93 still in it.) I started going down the road and after about a mile I noticed the exhaust tone changed and got more quiet. I'm talking I cant hear the exhaust at speed anymore over the wind noise, its that extreme of a change in the sound. The little vibrations I normally felt also went away, which confused me because I thought it would react the opposite. Since I had my jet kit installed, I noticed my bike was bogging down a little in midrange, around 5-7K rpms, after putting the 89 in it, damn if that didnt go away too, the motor pulls like it should the whole way to 13. Pretty much on the whole rpm band I feel more power, kinda like my bike woke up. This is all pretty strange to me, but I am assuming that since I was using a higher octane (less volitile) fuel (93) that all the gas wasnt being burnt up in the cylinders, and with the 93/89 (more volitile) mix, all or more of the fuel is being burnt. Does anyone agree with me? I noticed no pinging either. I guess either #1 my bike has lost a little compression, or #2 the extra fuel my jet kit is sending through has something to do with no pings. What do you guys think about this? I just thought it was kinda interesting and I'm curious if others have found this too... On a side note, my bike has about 40,000 miles, and the motor went through a rebuild with the previous owner about 8 thousand ago.

 

What level of elevation are you at? Cause I put 87 and 84 in mine (well 84 when im at 5K higher then sea).

You should try putten in the lowest octane... I would think the jet kit is what fixed the mid range slug and then pinging (prolly more gas can go in).

More octance doesn't really do anything for a car/bike that runs on less octance (talk to chemical engr. and they will tell you the samething).

 

THANK YOU!!!! I'm so tired of people who think they have all the answers basically calling me an idiot for saying, even providing a link that proves, that the best gas to run is the lowest octane you can run without detonation. This way all of the fuel burns and you're not wasting any gas. By the way, did you notice if it was any easier to start? When I swapped from 93 to 89 octane in my 1000, it lowered the number of rotations to start from around 9-10 to around 6 or 7. And the bike runs better, also no detonation.

 

No prob man, I was just stating the truth, and from everything I have seen, your assumption is correct. As far as the starting goes, my motor always comes on right when I hit the button with full choke, and I keep a little throttle in and go to no choke right when it catches so I dont screw my plugs. Another thing I noticed tonight is that at idle the rpms bounce a few hundred rpms more up and down, but overall I can tell the engine is performing alot better.

Van_nav, I think you missunderstood what I was saying about the jet-kit. After I got the jet kit installed, my motor was bogging down in the midrange, I think because the mixture was a little to rich in that area, but with the lower octane fuel, all the fuel is burning and I no longer have the hole anymore. I am gonna experiment further once I get the tank filled with 100% 89 octane, and then do a 89/87 mix and see how that goes. I have a feeling the way my motor sounds right now that I'm not going to be able to go lower than 89 octane, but we will find out.

My only question now is, I wonder how the extra fuel from the jet kit will react in respect to detonation, vs an F2 with stock jets.

Oh, and I am at around 2,000-2,500 elevation

 

hell i run 87 in both my cbr and gsxr 1K with no problems at all. always have and always will.

 

good job meng! also note that when a manual specs for like 87, 89, 91...make sure to find out if it's RON, PON, tec....aight? aight...

 

You know..........Im glad you wrote this. I always run 91-93 in my bike and yet know full well I dont have to as the compression is no where near high enough to need it. I have run 87 before, but not for extended periods of time. I will try it more often. Thanks.

 

I just run 91 i mean it does not cost me more than $8 at the pump when i fill up so it does not really hurt my wallet or anything. I mean damn... if i was driving a motorhome or something that took like $200.00 to fill them i would stick with 87 :P

 

True, but it's not all about money. Some performance is to be had by running the lowest octane gas you can get away with before detonation happens. It allows for a more complete fuel burn, optimizing performance. (How ever incremental it may be).

 

Just an update, I ran a full tank of 89 now, the bike is running even better than it was. Next tank will be 2 gallons 89 and 3 gallons 87, and I'll post back up. Not trying to bore you guys, I just find this interesting.