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I got a message from someone concerned about their gas mileage. I typed up a long reply and then decided that maybe I should post it for the general population to see, so here it is.

Fred
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You probably need to do some actual MPG calculations and see what you get. I typically get between 90 to 100 miles when the gauge hits the halfway mark. Typical mileage on a GL1800 is about 32-38mpg, depending on bike speed, wind speed/direction, temperature, load, tire pressure/type, altitude etc. I have gotten as low as 30 MPG while riding at higher speeds. Some folks will report getting 40 or even 42mpg on internet boards. If you ever ride with any of these guys you will understand why their mileage is so high. They ride nice and easy and don’t generally ride as fast as others. Personally, I can’t ride that way, but that is just me. I like to go fast and Texas highways make that easy to do.

Speed has a big impact on mileage, as does how hard you accelerate and brake (which also affects your tire mileage greatly). Colder winter temperatures also cause a drop in mileage. That is normal. Also, remember the lower your local altitude, the worse your mileage will be. Someone who lives in Colorado may get 5 or even 10 mpg higher than someone who lives near the coast at sea level. This is because the bike has a barometric sensor (BARO sensor) that tells the ECM to lean the mixture as the altitude increases. This also means that even a low or high pressure front can affect your mileage slightly.

You really don’t get a good data point comparing your mileage with someone else’s as there are just so many variables at work. Also, remember that wind drag has a pronounced affect on mileage. Aftermarket windshields are notorious for causing gas mileage reduction. So do highway pegs with size 12 boots hanging on them, and mirror air deflectors and baker wind wings. Anything that is in the airstream sucks horsepower from the engine and reduces mileage.

One real easy thing you can do yourself is to pull the spark plugs and check the color of them. If they are clean, then your bike is probably running ok. If they are dark or sooty, then you are definitely running too rich. This is probably the first thing I would do if I were you. Here are some photos of mine, this is about what they should look like:
http://www.pbase.com/image/14813796

There are two basic components to suspect if your bike is running rich and/or your gas mileage is abnormally low. The first things are the oxygen sensors. Many have reported having one or more (there are two in the bike) bad o2 sensors and that it impacted their mileage. I replaced both my o2 sensors about a week ago and my gas mileage went from about 32mpg to about 35 or 36 mpg. My o2 sensors had 40K miles on them. Standard advice on 02 sensors is to replace them sometime around the 40-50K mile mark. Here is a link to my oxygen sensor replacement photos:
http://www.pbase.com/fredharmon/o2sensors


The second component to check is the fuel pressure regulator. It is supposed to vary the fuel pressure in the fuel rail from about 41psi to as high as 50psi during high fuel demand situations. It isn't easy, but you can put a gauge on the fuel rail and check the fuel pressure at idle. It should be about 41 or 42 psi. If it is 45 or higher, then you may have a bad regulator. Here is a link to my fuel pressure testing I did:
http://www.pbase.com/fredharmon/fuelpressure

Also, depending on the mileage on your bike, you might want to think about replacing the air filter. A clogged air filter will reduce mileage.

In closing, if your mileage is anything over about 30mpg, there probably is nothing wrong with the bike. Monitor it over a few months closely and see how it behaves. As the weather warms up, it should improve by a few MPG. You can do things to help it, like keeping fresh plugs, oil, and airfilters in the engine and changing the o2 sensors when the bike gets near the 50k mark. Keep tire pressure correct, and don't add aftermarket devices that increase parasitic drag. And if you really want to improve your mileage, keep your speed under 60mph (if you can, you are a better man than me!)
 

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Fred....I'll disagree on some of your points. If your getting low 30's for mileage you have a problem. I don't care how hard you're running it, unless you are at the drag strip all day. The only time I have seen mileage that low on a 1800 is when my '01 had a bad O2 sensor(s) from the factory. After they were replaced along with many other parts the mileage went straight to 40+. The bike performed fantastic, but the mileage really stunk for the first 7,500 miles.

I get a constant average above 40mpg. I doubt many people ride a Wing harder than I do. I ran from north of Atlanta to Clearwater, 500+ miles, at a almost constant 85 mph and still got in the 40 range. Much of that was with the cruise on.

In the mountains my mileage will jump into the 45 range. I play harder than almost anyone I have ever met in the hills. Altitude means a great deal toward fuel mileage.

The way I understand fuel injection, a dirty air filter won't change the mpg much if any. The injection system corrects for the restriction. Maybe if the filter is 85% clogged, then that might make a difference. In a carbureted vehicle it will draw more fuel because of the extra vacuum it creates when you have a restriction such as a dirty filter.

I've checked almost every tank of fuel since my first 1800. That is over 46,000 miles, most of that at sea level. These figures are not corrected for speedo error either. Of course 99% of the people check their mileage with indicated miles, not corrected. My results are with 20/50 Castrol Syntec Blend oil and 87 octane fuel.
 

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Discussion Starter #3
I forgot to mention, I am using a Yellow box which corrects for speedo/odometer errors. My odometer error was about 5%, so my true mileage is 5% lower than before it was corrected. That means my current mileage of about 34-38 MPG would be about 36-40 if uncorrected.

Also, remember that this bike does not have a mass airflow sensor in the fuel injection system. This means it does not measure air flow density and account for variations. The only feedback devices to the ECM are the oxygen sensors. An oxygen sensor can tell the ECM to lean or richen the mixture, but only within a small percentage range. I doubt it has enough range to adjust for a clogged up air filter, but I could be wrong (have been before).

I occasionally hear reports like yours where folks claim they get 40+ MPG but don't ride like Gramps. I think they are in the minority. Most of the reports I hear are folks getting around 34-38MPG. It could be that if you are getting 40+ MPG that your bike may actually be running too lean. You might want to look at the spark plugs and see if they show signs of blistering. If an injector was clogged it probably would make your mileage go up, because it would lean out the engine.

Also, don't forget to correct for odometer error when reporting gas mileage, so that we are sure to be comparing apples to apples.
 

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One other thing I noticed. Red, you are apparently from Clearwater Florida. The terrain is extremely flat where you live. I typically ride in much more hilly terrain than you. I wonder how much of an impact that has on mileage. I bet it is significant. Another thing to note. Here where I live in Texas, it is ALWAYS windy. And I mean windy. I frequently ride in 30mph and higher cross and head winds. That also has a huge impact on my mileage. As does my Cee Baileys windshield (I lost about 2mpg when I put it on). Windshield height is also a big factor. Additionally, my home altitude is only about 600ft above sea level, which is fairly low. All these factors conspire against me resulting in poor mileage. My right wrist doesn't help any either.

When I travel two-up and fully loaded long distance, I tend to get slightly better mileage. I attribute most of this to the fact that I am usually traveling at much higher altitudes and at slower speeds. However, I have sometimes wondered if the GL1800 doesn't actually waste horsepower when riding one up and single, and not operate in the most efficent range of it's power curve. Could it be that loading the bike down actually makes the engine perform more efficiently??

As you look at all the variables, you start to see why I think it is not a good idea to compare mileage figures. Looking at spark plug color is probably a far better way to determine if your bike is running lean or rich.



 

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Fred--

Your mention of what effect riding double might have on gas mileage got me thinking.

It seems to me, given the rather serious turbulence effects often complained about by our SOs, that they might be having a salutory effect on the airflow (and thus the gas mileage) by filling in the space behind us.

I don't know if this observation has any credence, but if it does we may need to rethink comments such as "you're a waste of space" when engaged in connubial discussions. :D
 

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Discussion Starter #6
Interesting point on the turbulence effect. There could be some merit to it. I can tell you that having my wife on back makes the bike handle better in turns. It plants the rear tire and helps reduce the rebound on the rear shock. So there are yet more reasons to bring your SO with you when you travel.

But I am straying from the fuel mileage issue now, let me get back on topic.

Another thing that is worth noting is that the last time I used fuel injection cleaner (Chevron Techron), I actually saw a reduction in gas mileage on subsequent fill ups, by about 2mpg. I wonder if the cleaner allowed the injectors to work better and inject more gas, thus reducing mileage.

Also, as many bad o2 sensors as have been reported in various model years, I think it might be prudent to go ahead and replace them every few years (or 50K miles). Ron Ayers has them for about $90 each, and I suspect Hal also sells them for a good price. If they cause a fault light, you can also get them replaced under warranty.

Here is a link to a good site with some info on the o2 sensor topic.

http://oxygensensors.com/

And before you ask, I already called them to see if they could cross reference the o2 sensors on the Wing to a generic model. No luck.
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Why should I change my oxygen sensors?
A new oxygen sensor can improve driveability and lengthen engine life. Ultimately, you achieve a smoother running engine that is more fuel efficient. Feedback from the oxygen sensor provides closed-loop control of the injected quantity of fuel for optimum air-fuel mixture...enabling virtually complete combustion to take place. By providing closed-loop control of the mixture, it becomes possible to use three-way catalytic converters to achieve the maximum reduction in exhaust gas emissions.
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How often should I change them?
Your vehicle manufacturer recommends a specific mileage at which your oxygen sensor(s) should be changed. However, contaminants in gas and certain atmospheric conditions can drastically shorten the life of any oxygen sensor, therefore they should be checked with every periodic maintenance and changed if necessary. Click here for a visual reference of oxygen sensor problems as well as diagnostic procedures.
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I couldnt log into this chat board since early last evening. So my post is a tad late...however, here it is. Red, I somewhat agree with your analogy about fuel mileage. Having said that, I also agree with what Fred has said. Too many variables to make a blank statement as to what the gl1800 should get for average fuel mileage. I only got into the 40 plus range when the bike was new and using uncorrected odometer readings. After I installed the yellow box, I got high 30's for mileage. Then my right 02 sensor took a dump, mileage dropped to 24 mpg. Dealer changed it, mileage went back to high 30's. Since then, roughly 15,000 miles, fuel mileage has stabalized at around 33...with occasional spurts to 36. I cruise at 75, do not attack twisties..am not hard on the throttle. I concur with fred that at higher altitudes..I get my best mileage. can reach into the low 40's..have done this a few times. I ride basically at sea level, which gives me the worst performance. Winter fuel mix also gives me the worst performance. Now I am wondering what Fred meant by changing the 02 sensors. Fred, are you saying the 02 sensors diminish in performance like spark plugs do compared to new? If I thot my 02 sensors were faulty, I would have the dealer change them. Everytime I pull my plugs, they look like your pictured ones. I have yet to perform the fuel pressure test but I am very close to getting that done. If anything is wrong with my mileage, I am suspecting a faulty fuel pressure regulator....(running at too high fuel pressure). If the pressure test shows around 42 psi..there is nothing more I can do but to drive the bike and accept what it gives me for fuel mileage. However, if the pressure test shows a high value...the dealer will be getting a phone call. btw, I have a new air filter installed. My fuel mileage did not change from old air filter to new..filter was changed out at 18,000. Fuel mileage was not affected by new spark plugs either...mileage is the same with old or new...those were changed at less than recommended mileage.
 

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I just read these posts with curious interest. My bike and I have only been together for 4200 miles so far, but, using uncorrected numbers, I have an average overall to this point of 41.3 mpg and a high of 49.2 mpg.

I don't ride like a grandpa, I'm ONLY 44, and my last bike was a Ninja 900. Still have a little of that in my blood (and to think my wife thought I had grown up when I bought the wing!!).

I live at 1260 feet in elevation and the best tank was riding around Mt. Rainier at a much higher elevation.

Maybe I just got lucky! :lol:

Paul H.
 

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elevation will always better your mileage on the 1800. I get my best mileage at elevation. Mileage also depends on the area you live in..I live in so. calif...our gas is loaded with crapola emission control additives..which also serves to give less mileage.
 

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I live in the same area as Fred. I have the Cee-Bailey shield, all of the Baker Air Wings and have the Yellow Box and get right at the same mileage described by Fred.

My point is that when the wife is riding with me, I DO get slightly better fuel mileage. I am sure that I know why! The pokes in the ribs, banging on the helmet and shoulder blades, and the continuous noise on the inside of the helmet make me alot less aggressive with the right wrist. :roll:
 

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My point is that when the wife is riding with me, I DO get slightly better fuel mileage. I am sure that I know why! The pokes in the ribs, banging on the helmet and shoulder blades, and the continuous noise on the inside of the helmet make me alot less aggressive with the right wrist. :roll:[/quote]

Orange Bandit...I have a set of anti-rib pokers..ifn ya wanna borrow em..... :D :D :D
 

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Discussion Starter #12
To answer your question about oxygen sensors, yes they do wear out. They are considered a tune-up item and probably should be replaced around the 50K mark. They have a thin platinum plate in them that detects changes in oxygen levels and produces a small voltage relative to the oxygen content change. Over time, the platinum plate becomes contaminated and ceases to function to its original specs. How soon it becomes contaminated depends on a variety of factors and I know of no way to really test one to see if it is working up to spec or not. So it is just easier to replace them at a given time period.

Also, it is worth noting that anytime I disconnect the battery and go through the ECM reset procedure, my first tank of gas afterwards seems to be slightly higher. Once the ECM re-learns the o2 sensor readouts and how I ride, my mileage settles back to it's original settings. For example, last week I replaced my o2 sensors and reset my ECM and the first tank afterwards I got 39mpg. The second tank dropped to 34mpg. I also saw a temporary jump after the ECM was replaced. It seems like once the ECM reads all the sensor data over a period of time, and decides on what bias factor values to apply to the fuel map, that it ends up richening the mixture. When first reset it must use the factory default values for a while it gathers sensor data.
 

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Fred H. said:
and I know of no way to really test one to see if it is working up to spec or not.
Testing is fairly easy, Fred. Contact me by E mail if you want to discuss it.

Stu O
 

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Stu_O said:
[quote="Fred H.":38m8pdb2]and I know of no way to really test one to see if it is working up to spec or not.
Testing is fairly easy, Fred. Contact me by E mail if you want to discuss it.

Stu O[/quote:38m8pdb2]

Stu...is testing of 02 sensors a big secret?....be nice to share on the board how to do it and let all the board members that are interested in knowing how to do such.
 

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gas mileage

While on the subject of gas mileage, has anybody seen a gas mileage excel chart. I am looking for one. Someone posted this excel file several months ago as a downloadable file.
Thxs, Mike
 

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I dug out some old gas receipts. Going over the rockys I got 42.3 mpg corrected mileage (yellow box). prior to that gas load, i was getting 33...after that load..i got 33. now, I carry a 5 gal fuel cell. So I was filled up prior to crossing the rockies....going from west to east on I-70 filled up in St. George Utah. Didnt fill up again till after the rockies...cant remember where it was ..but was on the flats of the plains. I can go about 400 miles before refueling ..if i get good mpg. so, in order to attain that 42.3 mpg figure...I had to be getting even better than that ...prolly was hitting very high 40's. reason I say this, there was a good bit driven on the flats before and after the rockies. so all this tells me...I wished I was driving in higher altitudes all the time. sure is a nice feeling to be in the forty bracket with fuel mileage. I think the one pass is just a wee tad under 12,000 feet or maybe 11,000...somewhere around there. Bike also runs best at that elevation..more power ..more fuel mileage..more pickup and go..more horsepower..thats my experience anyways.
 

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I keep pretty decent records of my bikes fuel mileage and agree the mpg is usually higher at higher altitudes. Have actually been as high as 51 mpg a few times. The lowest was 29 mpg on a 180 mile stretch of 2 lane hiway with serious wind and an average speed of 90 mph. With 43000 miles my bike has averaged 43 mpg on mostly the cheapest gas I can find.
 
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