What fuel for CBX??

[djpauw]

Hey guys

I would like to know what type of fuel is best to use in a CBX motor, perhaps some different experiences from you and what to.look out for generally.

Over here we generally have unleaded and LRP (lead replacement petrol) available but others can also be found with a little effort.

Thanks

[6Pipes]

In my neck of the woods the only option is 10% ethonal / 93 octane. I have never had any problems with it but at the end of every riding season, I always drain the tank and the carb floats and then run the engine until it will run no more. Thus far, no issues with the ethonal fuel.

[Rick Pope]

In my neck of the woods the only option is 10% ethonal / 93 octane. I have never had any problems with it but at the end of every riding season, I always drain the tank and the carb floats and then run the engine until it will run no more. Thus far, no issues with the ethonal fuel.

Don't forget that the lowest point in the system is you accellerator pump circuit. As your engine sputters, give it a few quick pumps and you'll get the last of it out.

[steve murdoch icoa #5322]

Eethanol-free 91 octane.
I notice less "popping/burbling" on deceleration.
Quick, wrap up this thread before EMS gets back from Germany. lol.

[6Pipes]

In my neck of the woods the only option is 10% ethonal / 93 octane. I have never had any problems with it but at the end of every riding season, I always drain the tank and the carb floats and then run the engine until it will run no more. Thus far, no issues with the ethonal fuel.

Don't forget that the lowest point in the system is you accellerator pump circuit. As your engine sputters, give it a few quick pumps and you'll get the last of it out.

Always!!

[djpauw]

So unleaded is OK? But preferably no ethanol although the motor can cope with it...?

Anything else?

I noticed somewhere someone mentioned using Avgas....? Anyone's take on that? Or anything else?

[EMS]

If you ask this question often enough, you will inevitably get responses from braggarts and know-it-alls who will tell you to only use race gas or aviation fuel and maybe at the same time try to turn you away from DOT3 or 4 brake fluid because of the ill effects of it.
I currently own 15 motorcycle dating from 1971 to 2012 and all of them run quite well on common pump gas, all of it with ethanol. I have no other choice where I live.
I use lead additives in the 1971 just to be on safe side regarding valve seats, but I have occasionally used regular gas in some bikes that ask for premium and take advantage of the knock sensor and the automatic ignition retarder/advancer. The only bad thing I have encountered from using ethanol is that the fuel level sending strip in one of the BMWs stopped working correctly. The CBXes get 91 or 93 octane and run fast enough for me with it.
You need to do what you think is best for your bikes and if you have enough money, race gas or aircraft fuel is perfectly fine.

[djpauw]

Thanks EMS, that is really insightful. Over here in Namibia we have just a normal Unleaded (I think 95) and the LRP (Lead Replacement Petrol - I think 93) at the pumps. And if the reports in newspapers etc are true then we will no longer have LRP within a year or so.

So essentially what is most important for me to know is if my CBX would be able to handle the Unleaded fuel, which it seems it would...?

Secondly if there is any significant reason to get some other fuel I would like to hear that and consider doing so, but this is strictly optional as I am also realistic about the fact that I am not going to use the bike for racing or some such. Haha.

Oddly enough I just noticed that none of the websites of our local fuel suppliers give ANY indication of the presence and quantity of ethanol or any other chemicals and stuff in their fuels. There is really no technical info available. Instead they just ramble on about how smooth their fuel makes your engine run and how it contains "detergents" that leave your fuel lines etc cleaner etc etc... All a bunch of stuff that no-one can probably prove OR disprove for that matter. Not helpful at all.

[Rick Pope]

I doubt that your fuel has any ethanol. It was originally used here as a replacement for MTBE, which is another source of oxygen in the fuel, but pollutes water sources.. Oxygen rich fuel is require in the USA to reduce the brown fog, or "smog", that we had in the '70s and '80s. It seems to have worked.

One problem over here is that ethanol, being cheaper and higher octane than straight gasoline, often gets blended at more than 10%. That's when the issues tend to crop up.

[bigsixman]

I have 11 older Japanese bikes and a 2007 Harley and I use 91 unlead in all of them on a regular basis for driving. At the end of the riding season here in MN I run as much of the 91 unlead out and switch over to av gas for the winter storage. I have done this the last 4-5 years and I have had no varnish or gumming up of the carbs due to the av gas having a multi year shelf life and drying up clean. I had problems prior to that and they are gone after the switch to av gas for long term storage. In MN, we can end our riding season in Oct. and the bikes can sit until May. I use it in my generators year round because some years they get little use and there's no varnish issues when it comes time to use them. The local agricultural museum uses av gas in all their gas tractors and others equipment that uses a gas engines and it has cured a major carb problem for them due to the equipment sitting for long durations without use. I just purchased 6 gallons of av gas at our local airport for $5.38 a gallon. When we go to Sturgis in August there's a station that sells 94 octane unleaded fuel and due to the elevation and high temperatures, the Harley responds to the higher octane fuel over the normal 91 octane fuel.

[EMS]

When we go to Sturgis in August there's a station that sells 94 octane unleaded fuel and due to the elevation and high temperatures, the Harley responds to the higher octane fuel over the normal 91 octane fuel.

I am interested to hear how your Harley responds, exactly?

[bigsixman]

EMS: In August at Sturgis the temperature is 90s to 100* most days and pulling the hills in the heat two up the motor will sometimes detonate due to the weight, temp and the elevation changes. The power is slightly better with the 94 octane I assume due to the computer allowing more advance. We have a group of nine that go out there every year and the 94 octane works on the Harleys, but appears to due little or nothing to the water cooled bikes that ride with our group. Our Harleys are stock as was a Victory Hammer that went with us in 2010 and he felt his bike responded to the throttle better and overall ran better in the conditions. I think that the additional weight of the passenger and additional gear work a stock Harley pretty hard and the better fuel lessons the power loss in those conditions. When I get home after Sturgis and still have the 94 octane fuel left in the tank I notice no difference with our 800' elevation flat lands between the two fuels.

[EMS]

The interesting thing is, that with higher altitude and thinner air, you get a lower mean pressure above the piston due to the slightly lesser filling and the motor should be less prone to detonation. Also, the compression ratio of a stock Harley doesn't really require a high octane fuel as 94. I have been to Sturgis many times also on Harleys, always riding two-up. I always found that the massive torque the motors have at low rpm, they made short work of the hills. And those were carburetted EVO motors. The only time I had a motor knocking was after a spirited run on I-90 from Spearfish to Sundance when we hit in excess of 80mph. Just my experience.

[bigsixman]

EMS: Is it the quality of the local fuel sold in the Sturgis area? I agree with everything in your above post as it all makes sense to me. I do not consider my 96" HD as having an abundance of torque, good, but the motors work hard in the heat and two up. We run alot of the slow two lane black top back roads to avoid some of the bike week traffic and it works the motors pretty hard with the slow curves and hills in that heat. I agree with you on the high speed roads like I-90, the bikes work fine in that environment.

[EMS]

Maybe it is the fuel, but it could also be your controller, if you have a fuel injected motor. It may want to overcompensate for the normally richer mix at higher altitudes.