MPG

[JARichmond]

I'm about 5'8 and 150#. Running 142.5 and 145 mains with pods and stock exhaust. Usually I don't run high octane (89 or 87 with some Seafoam). With about 25km of city riding and 135 of highway riding, I averaged about 45 mpg. Looks like I'll have to start shedding some weight and shelling out some cash for 93 octane.

 

[arfstrom]

I don't think Octane level has anything to do with anything. unless your only a weekend rider. If you use the cheaper octanes, with the corn syrup additives, you have to dive it daily to every couple days. The classic car gas you will have less to worry about, but then you will be shelling out $$. or we (me included) can shell out some $$ to the local YMCA or local gym, and disappoint our favorite barley beer makers. Can we be skinny and be able to drink????? Or is it the Skinny people only drink, and never eat????? (still over 210 lbs)

 

[16VGTIDave]

Ethanol is a big part of the problem. It reduces performance and fuel mileage. Yes, it will increase the octane of gasoline, but very few vehicles require the higher octane. However, the reduced energy of the fuel, as well as the damaging effects to brass, rubber and some other alloys makes it one of the worst things ever forced on us. Has ethanol reduced our dependance on foreign oil? No. Has it reduced vehicle emissions? No (burn ethanol with gasoline and you get formaldehyde, the same stuff we embalm our dead with). Has it made a few people wealthy? Yes.

I have been able to document improved mileage and (up until recently) lower cost per km (or mile) by using ethanol free gasoline in my bike (16,000km tracked) and my car (75,000km tracked). My wife's car doesn't care so she runs the crap because it is cheaper for her. With premium gas (the only ethanol free I can get) jumping in price the past months, the cost benefit has disappeared. The improved mileage/performance and lack of maintenance issues makes it worth while to me though.

 

[arfstrom]

Make sense. $$

 

[JARichmond]

Changed my jetting and riding style around and got a solid 60 mpg (3.92 L/100km) on the highway with ethanol-free gas.

 

[16VGTIDave]

That is outstanding fuel mileage! When you say "highway", what speeds are we talking about?

 

[JARichmond]

Anywhere from 80 to 100km/h. I make the jaunt from Hamilton to London frequently and like to take the back roads through Paris and Woodstock. I'm looking to mount a windshield I have laying in my shed for extra slipperiness.

 

[16VGTIDave]

LOL. Okay, so you are cruising at speeds 20kph lower than I typically do. And you are riding in my back yard! I'm in Drumbo, which is 20 min from either Woodstock or Paris. You should stop by some time you are passing through!

 

[JARichmond]

I'd love to stop in and visit another xs400 member in the flesh!
I'm still getting used to high speed riding, so I'm cautious with how fast I can go. If I'm doing the maths correctly, wouldn't riding at higher speed result in better fuel economy? the way I see it, you're operating the engine at a certain rate, consuming x liters of fuel per hour and the bike is going at y distance per hour. If you're in an overdrive gear, the engine is spinning slower than the wheel is, so although you may be consuming an extra bit of fuel, you'll be going significantly faster, and thus operating the bike for a shorter time.
Does this make sense to anyone else?

 

[Lou Ranger]

If the engine's most efficient rpm results in a higher highway speed than your normal, then you ought to burn less gas.
However, while the engine will be willing to rev higher, it's efficiency will start to drop again as you go beyond the sweet spot and mileage will drop.
I suspect this is why computer controlled cars with cvt transmissions can deliver amazing mileages if you drive around with the setting on "granny".
It will keep the engine at or close to the efficiency sweet spot all the time.

I can't even imagine where the efficiency sweet spot is on a 30+ yr. old 400 cc bike engine. I doubt if it was much of a consideration at the time, lol

 

[Scorpio1963]

I have to say my xs has got best fuel economy ever since I owned it.so far this year I haven't burned a drop

Dave

burn ethanol with gasoline and you get formaldehyde

Does that harm the environment?

 

[16VGTIDave]

Aerodynamic drag increases exponentially with speed, not linearly. That is why going fast takes significantly more power than going slow, especially on our "naked" bikes.

JAR, shoot me a PM next time you plan on coming through and we'll see if we can meet up.

Scorp, formaldehyde is toxic to all living creatures, so the answer to your question is a resounding YES! It is what makes your eyes water and throat burn when you get stuck behind a vehicle burning E85. But they don't test for it when measuring vehicle emissions, because they don't want the information out there. No, it isn't a conspiracy theory, it is just a conspiracy to make a few even more wealthy. Even Mr. Al Gore has recently admitted publicly that ethanol in gasoline was a bad idea, despite his shoving it down our throats. Literally...

 

[Scorpio1963]

Dave thanks for the info very intriguing to say the least.I don't believe or know if I have ridden behind a vehicle burning E85,from what you say Id know right away if I was.Seems like everything our gov does to our fuel has some harmful affect to the environment.Also I read that hear in Michigan the state gov is to increase the amount of ethanol to E20 soon.I didn`t get an exact time frame from the article.You think with the droubt in areas of our country there wouldn't be enough water to grow corn for making the stuff.

 

[arfstrom]

Weight has to play a role in this equation too. The higher the mileage, the lower the drivers weight.

 

[16VGTIDave]

Weight certainly is a factor, especially when accelerating or climbing grades. But it is less of a factor when maintaining a steady speed.

 

[vismajor]

I'm trying to calculate my estimated miles per tank so I can be aware before needing to switch over to the reserve fuel. I'm resetting my trip odometer when I fill up, but how are all of you measuring fuel used per ride?

(sorry if that's a dumb question - I'm a new rider & my XS400 is my first motorcycle.)

Thanks for any advice you can give.

 

[arfstrom]

Our tank is generally just over 3 gallans, about 110 miles I will need to flip to reserves, and then once I get gas, I go to Fuelly.com and log my fuel info, then it spits out a MPG number. first tank 2 weeks ago was 45MPG, then yesterday, it was 39MPG. I also roll the trip counter to Zero.

 

[xschris]

My xs400's get around 55-65mpg. I fill them up, ride the bikes for a while then fill it back up. Most of the time (when I am testing for mpg) I have gone 55 miles on my modded 80 and 65 miles on my stock 79 and can fit 1 gallon in the bike to fill them back up.

 

[vismajor]

Thanks for the help.

 

[vismajor]

Thanks.