fuel

just curoius what gas you guys run in your XJ's. I found mine to run best on 93 as far as performance and mpg. The side cover says minimum 93 octane LEADED. The guy before me ran 87 unleaded and i run 93 unleaded. no problems in 4 thousand miles. I was just wandering what grade fuel everyone is running and leaded or unleaded.

 

on the inside of 1 of your side panels you should find a sticker mine says 91 octane or better . I also use 93 octane. if you feel the need get a lead substitute from the parts store , I haven't use it not having any problems. from what I have heard we should't worry about the lead issue.

They don't make leaded fuel anymore that I know of

 

I run High Test; too.
But, I have the Mixture's running a shade on the Lean side.

What gas you run is up to you.
You don't need High Test.
There's lots of different tires.
Lots of different Batteries.
They make Synthetic Oil that motorcycle safe, now.

 

you run it lean because of the volitility increase of 93 octane?

Smaller squirts (Lean) of 93 octane gas = normal size squirt with recommended 91 octane

?

 

I run non oxygenated 92 octane in my bikes, Its not as bad for the carbs and it lasts longer sitting in the tanks.

 

?
non oxygenated fuel? explain

 

I run what ever's cheapest.
Might run a tank of the good stuff now and then.

 

"From January 1, 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the US. However, fuel containing lead may continue to be sold for off-road uses, including aircraft, racing cars, farm equipment, and marine engines."
It is still available.
I was about to say when I was in Arizona they had leaded at just about every station, then I realized that was in '92.
:lol:

 

lol

go to the airport to fill up

 

He runs the 93 octane because his mixture is lean.

Lean mixture = burn fast = detonation
High octane = burn slow = less detonation

 

was just curious about the leaded thing. I'm sure with 38,000 miles and 7 owners the bikes probably seen alot of cheap unleaded. I just choose the 93 over the 87 because i get about 4- 4 1/2 better mpg. no real power difference felt. My friend calculated the "cost per mile" as he calls it and it worked out cheaper to run the 87 but i like to see 58-60 mpg instead of about 55 or so. and yes it does say 91 or better i think i typed 93 before.

 

I run premium because of the Norton.

Let me explain: The Norton is a vertical twin, but not really. It's a "twingle." Both cylinders use a common crank throw and go up and down TOGETHER not logically like a bicycle pedal crank. The spark occurs on alternate cycles so they call it a twin, but it SHAKES. That's where fuel comes in. I can tell the difference in fuels by how long it takes my right wrist to get buzzed to death. (Trips to Canada are LOADS of fun---sorry but you guys have crap gas compared to us...) So I run premium in the Norton and it is much happier. I figure if it's happier, the XJs oughtta be happier too although I really can't tell any difference.

 

I think this has been discussed many times and to be quite honest I don't get 4 1/2 miles per gallon difference when running high grade. If you do the research you'll find that these bikes, at least the 82s where made to run on 87 octane. In my experience the only time when I see that great an improvement is in my high compression motors. These bikes do not fit that catigory. In the lab you will find that 87 is more explosive, it burns faster just not a completely. Higher octane will burn slower but more completely but needs increased compression to do so. Yes? Am I wrong?

Isn't this the same reason that top fuel drag cars are able to run straight, or darn near it, alchohol. It needs the increased crompression to combust efficiently.

I have done many comparisons of the fuel available in my market; 87 w/10% ethanol, 89 w/ ethanol, 91 w/ethanol and 91 straight. I even ran some 93. I could see little to no difference.

Maybe my carbs, valves and cylinder heads need some work. Maybe that would show me a difference. And for those detractors of ethanol that say they blow up motors or cause other ills, Yamaha ran a 5 year test on car, motorcycle, and boat motors and found that there is no ill effects from ethanol to be found, infact they said that their 2 stroke outboards performed better and showed improved wear resistence with the ethanol blend and only very slight increase in fuel consumption.

I know that ethanol is an expensive fuel to produce and don't want to go down that road but at the pump here in the upper midwest it's some cheaper. I think running the "good" stuff is throwing good money at maybe marginal benefit.

I may be way off on this but it's how I understand it. Can some one correct me if I'm wrong?

The Buff

 

Often so.

Without going into too much elaboration, when there is detonation energy is going toward pounding the engine instead of moving the vehicle down the road. In those cases, higher octane will improve fuel economy.

If the machine doesn't detonate on 87, putting a higher octane is the same as throwing money on the ground.

There are some legitimate issues with ethanol:

1- less energy density reduces mileage.

2- ethanol will damage some rubber compounds. I do not know if the o-rings and such on the XJs are at risk for this.

3- ethanol will mix with water. BIG issue for marine uses where the environment is high humidity. Can also be a problem for a metal fuel tank and a long storage season.

Now for the best part - ethanol is a cheap octane booster. Higher octane fuels are more likely to have ethanol blended in.

 

well said! i would also like to add that here in the states, all pumps are now pushing minimum of 10% ethanol in place of mtbe, so really the chances of pinging on 87 are slim with these low compression bikes. even when running lean i had no issues on my 750 running 87.

 

I still see stations advertising "No ethanol!" around here..

 

I usually run 87 octane fuel with good results. I ran some 85 octane gas in my bike last year in the Black Hills, to stay away from the ethanol blends. The bike did not run very well at the higher elevation with the lower octane gas. I will be cleaning my carbs this spring and I will be breaking the rack to replace all the o-rings on the fuel rails and will be replacing the seals in the petcock as well. I have heard the stories of ethanol fuels being hard on old rubber, so I am replacing everything that I think can be hurt by it. It's getting harder to find gas without ethanol so I might as well have the bike set up to accept it.

 

I have run ethanol in my bike for 6 years since purchase and the PO ran ethanol for years before that. The PO had the carbs done 2 years before I purchased and they haven't been touched sinced. I will be redoing my carbs this spring. and will let you all know if the rubber parts come out in pieces. but as of early November I only saw a small decrease in performance over what I had when I purchased the bike.

The upper midwest is the eppicenter of the ethanol trade. Most everyone uses it in in everything from cars to bikes, tractors to lawnmowers, boats to ultralights. There just doesn't seem to be alot of credible opposition.

I said it before and I'll say it again; I may be all wrong. I don't claim to be a genious, I just go on observation and experience. So far so good or I missed something.

The Buff

 

Ethanol blended fuels here in MN seem to attract moisture. Since my bikes sit most of the time I noticed that the float bowls would get white and frosty inside with corrosion. I have switched to non oxygenated fuel. (availabe at my local station) It has no ethanol and is more like the old gas we used to get several years ago before the goverment required the blending of ethanol. I would bet your carbs are the same as mine were before I switched. I also had my gas tank on my black 750 started to turn red inside. I have to clean that out again also. Let us know what you find.

 

wow! its been about a year since i have seen non-alky fuel at a pump anywhere around here! there must have been a bunch of holds full of the old stuff out by you. send some my way, my wifes mustang DRINKS the alky fuel. she dropped about 1.5-2 mpg when they switched over :x

 

You can stiil get the nonethanol fuel here as well but it is typically 85 octane, this is the same fuel that they blend with ethanol to attain 87 octane. I found one place that sells 93 octane for the hy-pro set but thats dumping money for nothing for most of us.

The Buff