How can I resolve such fuel Consumption !


Information and questions on GL1500 Goldwings (1988-2000)
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Alemayehu
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Location: Melbourne ,Australia
Motorcycle: 1992 Honda GL1500 SE
1983 Honda GL1100I Sold
1987 Honda GL1200I sold
1997 Honda GL1500A sold
1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

How can I resolve such fuel Consumption !

Post by Alemayehu »



Hello friends I have got very serious matter regarding the fuel consumption.First of all I should let you know the history of the bike.I use to have quiet a few of wings, CX and smaller GL models.I have learnt a lot where I need no one to fix my bikes having the help of all you guys and how to of this wonderful website.I sold all and moved to Australia and got very beautiful Bike.The Bike is 1991 GL 1500 California model imported from the USA new with 650 mile on it and was not registered for 28 years and kept in a garage.The PO (couple ) were collector's of vintage vehicle passed away one after the other.Family member sold all and the last one was the bike purchased by a young man who has a friend who owns bike shop.The bike was serviced there sitting almost a year to hunt parts from US one by one.The mechanic did good job change all necessary parts like new tires front and rear,fuel line,fuel pump,fuel tank,cleaned and serviced the carburetor ,all new fluid's ,Break,Clutch, and few things here and there to make it perfect.At last the young man didn't like the shape and the heaviness of the bike decide to sale it and I got it from him. I did change the cam-belt and did quiet few paint work.The Bike runs like a dream,no fuel leaks,no fuel smell,cold start with full chock and idles at 750 rpm in 60 sec or so.I did almost 1000 mile on it now it shows 3000 mile in total.I try to calculate fuel consumption and I only get 10 km in 1 liter of 91 unleaded petrol.I did used two or three full tank by mistake E 10.I use to have exactly same bike and I was getting a minimum of 15 km in 1 litter.I am not an aggressive rider and don't exceed 3000 rpm ( always under ) and always between 60 mph - 65 mph.I thought about it and read most of the questions and answer from the web and decide to change new air filter and those small intake filter and vacuum filter and no change at all.At last I went to the mechanic who did serviced it and who knows all about the Bike and asked him to fix if there is any thing wrong in the carburetor or any thing and he said I don't want to play up with it I can make it worse or may come up with no difference and I get shocked don't know where I should go.A friend suggested me a bit far away place well known bike shop to take it and get chucked still I don't know what to do next.Please help.


Jesus is Lord!

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AZgl1800
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Re: How can I resolve such fuel Consumption !

Post by AZgl1800 »

the 1500s MPG numbers can very by a large amount.

Depends on the how big the windshield is, headwinds, and your throttle hand.

If you are the slow type, who enjoys the color of the leaves ( in Australia? ) it will get 40 mpg, have seen some folks mention 46? which makes me wonder if their calculator is broken.

I owned two gl1500s, a 94 and a 98. both of them had the Tulsa Tall windshields which projects up above the top of my helmet. both bikes averaged 33 mpg overall on long trips, and writing down every drop of gas they used.

But, I lived in the flat wide open spaces, no trees to look at, and when I am going from point 'A' to 'B', I fly with the wind.
our speed limits are 65, 70, and 75, depending where you are.... and I push that +5 all the time.

so, 33-35 mpg is the best it will do for me..... except once, when I lived in Arizona and took a Foliage Tour, twisty roads, 35 to 45 mph.... one tank of gas got 40 mpg.
~John

'02 GL1800
2009 Piaggio MP3 250cc

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bluthundr31
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Re: How can I resolve such fuel Consumption !

Post by bluthundr31 »

That mileage is quite a bit lower than I would expect. A few tips, , , ,

1.) Some bikes don't really "like" 91 octane and its not really gonna help, , ,go with the 87 octane and see what the mileage is after two or three tank fulls.

2.) If you use the choke to start the bike, , ,MAKE SURE you turn it off the moment you start to ride.

3.) When you fill up the tank, mix in 1/2 (8 oz.) a bottle of Seafoam per tank. It'll help clean up jet and bowl "gunk" that might have collected as it sat for 10 yrs. Seafoam works best for me when I mix 2 oz per gallon of gas (petrol for down under). Seafoam works best on the "jets" if you keep the RPM's below 2k.

4.) When were the spark plugs changed last, , , maybe new ones are in order.

There is no "overnight" solution to poor mileage, all of these tips are meant for work and solve your issue after a few months of normal riding.

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bellboy40
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Re: How can I resolve such fuel Consumption !

Post by bellboy40 »

That is low fuel consumption for a 1500. If my math serves me right, that works out to about 23.5 mpg. That is a little over half of what I think it should be. I would think you should be around 16 or 17 km per liter.
Are you sure it is running on all cylinders? A miss will kill the mileage. Do you see any fuel leaks or have a strong smell of fuel from the exhaust? Maybe the brakes are dragging. These are some things to check on.

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ct1500
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Re: How can I resolve such fuel Consumption !

Post by ct1500 »

Unfortunately your experience is not an uncommon one. When these machines rolled off the assembly line years ago there were none of these wildly varying MPG reports. You don't hear much about 1800 MPG discussions, do you? Many will buy one of these older machines which may have a dubious repair or running history. The 1500 in its' design day (early to mid eighties) was the pinnacle of technology for a motorcycle with all the creature comforts and having to meet Federal requirements for emissions with carburetors no less. Most who chime into the Forums will report around 38-42MPG as the norm. There usually is no easy one sentence fix for these types of problems on something of this age and bygone technology and takes detective work of the many systems and sub-systems involved which usually involve carburation first or ignition second, sometimes multiple issues.

Visual inspection of systems is the first step, how is the ignition system, does ignition timing advance work, plug wires breaking down? Are all the vacuum lines properly routed correctly with no leaks, are there non OEM parts used in previous repairs. As mentioned earlier are brakes dragging, clutch slipping etc? Are vacuum lines leaking, Air Jet Controllers working, carb slide condition, Shot Air system leaks and working correctly, enrichment rod malfunction, hot air door closed for intake air, is the mixture too rich or lean, vacuum leaks at carb/intake joints, internal carb problems, etc, etc? All have to be looked at and checked off the list.

An engine power balance test is a good diagnostic test. :)
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CrystalPistol
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Re: How can I resolve such fuel Consumption !

Post by CrystalPistol »

Alemayehu wrote:
Thu Mar 05, 2020 5:59 am
Hello friends … etc … I try to calculate fuel consumption and I only get 10 km in 1 liter of 91 unleaded petrol.I did used two or three full tank by mistake E 10.I use to have exactly same bike and I was getting a minimum of 15 km in 1 litter.I am not an aggressive rider and don't exceed 3000 rpm ( always under ) and always between 60 mph - 65 mph.… etc …Please help.
What is that in miles per gallon?


It doesn't hurt running E10, been running it for years, no harm in running it. Potential for harm is more in long term storage. These bikes are not set up to maximize 91 octane fuels, 87 or 88 or 89 is perfectly fine and is what the timing curve and compression ratio are designed for. 91 octane fuel has a higher resistance to spontaneous combustion from heat & compression than 87 octane, but a teaspoon of each has the same energy. If a engine is built to run 87 octane, very likely the slower igniting & combustion resistant 91 results in lower power output, incomplete combustion, poorer mileage too.

There is a point in the power stroke where maximum leverage of the connecting rod to crankshaft throw is achieved. Timing is all about ascertaining that the maximum energy is released by combustion to take advantage of that point. Too eary, you get preignition, too late you get a hotter motor due to more cylinder wall exposure to heat of combustion and lost opportunity for maximum power, compression is also lower thus slowing combustion (fuel can combust because of heat, spark, compression)

I can get mid 30s (miles per gallon) all day long two up, have exceeded 40 on occasion, but I seldom ride roads like interstates. 55-60 mph is about normal. I don't hustle from traffic lights either. I'll run 70-75 if needed on short legs on interstate if in a group, but it costs in mpgs once that tach makes a steady home over 3,000 rpm.

Mine is a three wheeled trike, has big rear air brakes called fenders, has two heavier car wheels & tires to spin up to speed, I have some minor exhaust help with an X-tractor, some say it's snake oil, but I know from past trials that it help versus OEM middle chamber. I also have the hitch and car rear axle weight that likely makes it a wash. I do use a K&N air filter, but also a 90 amp alternator so there's that drag too.

You could have some vacuum lines dried out and leaking too. I think someone mentioned choke, on a 1500 it's not so much a choke of air, but an enrichener throwing extra fuel in the mix, if left on it can use fuel fast so proper adjustment is imperative.
Make Courtesy your "Code of the Road" …

… & Have a Safe Trip!
:)

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Alemayehu
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Location: Melbourne ,Australia
Motorcycle: 1992 Honda GL1500 SE
1983 Honda GL1100I Sold
1987 Honda GL1200I sold
1997 Honda GL1500A sold
1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

Re: How can I resolve such fuel Consumption !

Post by Alemayehu »

Thank you so much for all your insight and sharing your experience about the 1500,to answer some of your concern's I don't see any leakage or fuel smell,I did chuck recently the front and rear break and no dragging or any issue there,the windscreen is the original factory one which is the normal size with air vent,of course I always feeling one way there is wind resistance,Fuel here in Australia either E10 & E85 Ethanol based , 91 Unleaded ,Premium 95 Unleaded or Premium 98 unleaded and I have been advised not to use Ethanol based fuel instead I use 91 Unleaded.In the mean time I have to chuck first I don't really know which type of fuel to run the engine all I know is, it is 1991 Californian model & love the shape and design of 1500's.Regarding the chock I always use for few sec and pull it back in full after the engine fires up.I think all the vacuum lines are okay but I am not 100 % sure but I will chuck it out very very soon.

CT1500 I appreciate your description you wrote me in depth & very detailed my next plan is to ride the bike a bit long distance using sea foam,and then an engine power test is next.By the way here in Australia one cane of sea-foam is 27 bucks,and I am planning to use home brew sea-foam and I would be very great full if any one of you suggest whether to use it or not even to think about it.
Thank you so much again I will let you know the result once I go through all of you guys suggestions and advice.I would appreciate if there is any one who is local whom I can communicate in person close to 3175.

Regards!
A A Fenta
Melbourne
Jesus is Lord!

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AZgl1800
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Re: How can I resolve such fuel Consumption !

Post by AZgl1800 »

on the 1500, you can use the lowest grade of E-10 while you are actively riding the bike.

the problem with E-10 arises when folks put the bike away for long term storage, and that is a real NO NO with Ethanol fuels and carburetors.

I run the E-10 down nearly empty, and then fill up with E-0 non-Ethanol gas....
I pour in some Sta-Bil Marine 360 first, then gas it up. that mixes the Sta-Bil with the fuel.

by the time you ride it home, the carbs will be clear of the e-10

Put the bike on the Center Stand for this:

now, to be a bit on the safer side, once you get it home, pull the vacuum line off the Fuel Petcock, place your finger over the end of the Vacuum line, and let the engine run until it starves out from lack of fuel.

that will remove most of the gas from the carbs, and the low speed idle jets won't clog up on you.
Once the engine dies, plug the Vacuum line back where it belongs....
~John

'02 GL1800
2009 Piaggio MP3 250cc

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CrystalPistol
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Re: How can I resolve such fuel Consumption !

Post by CrystalPistol »

AZgl1800 wrote:
Sat Mar 07, 2020 12:32 pm
on the 1500, you can use the lowest grade of E-10 while you are actively riding the bike.

the problem with E-10 arises when folks put the bike away for long term storage, and that is a real NO NO with Ethanol fuels and carburetors.

I run the E-10 down nearly empty, and then fill up with E-0 non-Ethanol gas....
I pour in some Sta-Bil Marine 360 first, then gas it up. that mixes the Sta-Bil with the fuel.

by the time you ride it home, the carbs will be clear of the e-10

Put the bike on the Center Stand for this:

now, to be a bit on the safer side, once you get it home, pull the vacuum line off the Fuel Petcock, place your finger over the end of the Vacuum line, and let the engine run until it starves out from lack of fuel.

that will remove most of the gas from the carbs, and the low speed idle jets won't clog up on you.
Once the engine dies, plug the Vacuum line back where it belongs....
I have kept my eye open for a brass 1/8" aquarium valve to insert in line.
Make Courtesy your "Code of the Road" …

… & Have a Safe Trip!
:)

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Alemayehu
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Motorcycle: 1992 Honda GL1500 SE
1983 Honda GL1100I Sold
1987 Honda GL1200I sold
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1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

Re: How can I resolve such fuel Consumption !

Post by Alemayehu »

Just updating all of you what I did and what I got. I ride the bike long distance with full tank gas and I have seen the fuel pointer needle pointing sharp at the middle of the gauge while it was 82 mile and then I have seen the red fuel light warning at 126 mile and then keep riding until it dies because of starvation of gas and come up with this figure which is 151.5 mile. Then I decide to chuck the spark plugs all where new just used about 1500 mile but for your surprise cylinder 3 and 4 are not firing. The cables are all fine chucked them 1 and 2 -- 23.6 k ohms - 3 and 4 -- 23.3 k ohms - 5 and 6 23.0 k ohms.The primary coil Resistance 4P WHT connector 1 and 2 3.5 ohms -- 3 and 4 1.2 ohms -- 5 and 6 3.6 ohms and lastly I try to chuck the Engine control unit 1 and 2 -- 4.1 ohms -- 3 and 4 -- 1.7 ohms and 5 and 6 -- 4.3 ohms.

Where do I need to go next from here do you think this can affect the fuel consumption any thought would be much appreciated.

God bless all.

Alemayehu
Jesus is Lord!

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bluthundr31
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Re: How can I resolve such fuel Consumption !

Post by bluthundr31 »

From what I see, , , #3 and #4 cylinders are your problem.

The readings from the coil and ECU point to a bad connection or a bad device for the #3 and #4 pistons. Try swapping coils to see if the "suspect" coil affects the #1 and #2 , or #5 and #6 piston which will prove that you need to replace that coil. The ECU is another issue, , but check the coils first, , prepare for the possibility of having to replace the ECU.

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Alemayehu
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1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

Re: How can I resolve such fuel Consumption !

Post by Alemayehu »

Hello friends I have got good news and here it is what has happens,yes bluthundr31 you are very correct,I have been thoroughly examining and trying my best to get from where the problem originates.While I was reading and studying all you guys wrote on the subject matter that I was troubled with on the how to and info and question page one morning the spark plug cable cap just snapped from the cable so easily with out exerting any pressure at all.The cap has to be replaced with new one.The new ignition coil was not functioning properly as well for cylinder 3 and 4 replaced with genuine ignition coil from Honda that fix's all my worries.I have done two trips and got the following result which never dreamed off.I got 79.1 mile with 6.69 lt of fuel and I was very careful not to accelerate over 2750 rpm at a speed of 60 m/h and the second trip I got 79.6 mile with 7.55 lt of fuel at 2750 rpm to 3000 rpm at a speed of 60 - 65 m/h. I will ride tomorrow a little bit longer trip hope I will have same result.Thank you every one for your advice and help.

God bless!
Jesus is Lord!

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AZgl1800
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Re: How can I resolve such fuel Consumption !

Post by AZgl1800 »

Alemayehu wrote:
Tue May 05, 2020 5:41 am
.....I got 79.1 mile with 6.69 lt of fuel and I was very careful not to accelerate over 2750 rpm at a speed of 60 m/h and the second trip I got 79.6 mile with 7.55 lt of fuel at 2750 rpm to 3000 rpm at a speed of 60 - 65 m/h. I will ride tomorrow a little bit longer trip hope I will have same result.Thank you every one for your advice and help.

God bless!
Being a dumb Okie from Muskogee, I could not wrap my head around your numbers,
so, I grabbed a Spreadsheet and let it do the numbers for us dumb guys up North
I suspect you will better numbers over a full tank of fuel, or about 175-200 miles ...


~John

'02 GL1800
2009 Piaggio MP3 250cc

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DenverWinger
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Re: How can I resolve such fuel Consumption !

Post by DenverWinger »

John, you might want to recheck your spreadsheet formula,

6.69 liters = 1.76 gallon, divide 79.1 mile by 1.76 gets 44.9MPG. or 19.02 km/l
7.55 liters = 1.99 gallon, 40 MPG, 16.96 km/l

Both very good!
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ct1500
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Re: How can I resolve such fuel Consumption !

Post by ct1500 »

A common theme when looking for help is the bike "runs great" or as in the first post "like a dream". I always shake my head no when reading of these problems. How can that be?
To Alemayehu how would you describe it running now on all six cylinders instead of four. :) Congratulations on your fuel mileage improvement. :D
Last edited by ct1500 on Tue May 05, 2020 9:27 am, edited 3 times in total.
Local and need repair help with your 1500, Valkyrie or ST please click contact
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Alemayehu
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Location: Melbourne ,Australia
Motorcycle: 1992 Honda GL1500 SE
1983 Honda GL1100I Sold
1987 Honda GL1200I sold
1997 Honda GL1500A sold
1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

Re: How can I resolve such fuel Consumption !

Post by Alemayehu »

Hello dear ct1500 and DenverWinger , thank you for the simplicity I am going to ride tomorrow a bit longer that the one I did and will find out how many km or miles I should get out of full tank and will let you know you guys.
To be honest with you ct1500 this bike is my second 1500 and I use to get like 16 - 18 km in one lt of fuel & for the one that I am taking about I was not in able to figure out or just to point my finger here it is oh no the bike runs great idles at 750 smoothly run like a dream of-course with out any thing to notice or indication but the only concern was fuel consumption is night mare and any way Six cylinder is a total difference,I said to my self what ? Any way I learn a lot and thank you so much for all you guys help and support much appreciated.

Thank you and God bless!
Jesus is Lord!

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AZgl1800
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Re: How can I resolve such fuel Consumption !

Post by AZgl1800 »

DenverWinger wrote:
Tue May 05, 2020 8:08 am
John, you might want to recheck your spreadsheet formula,

6.69 liters = 1.76 gallon, divide 79.1 mile by 1.76 gets 44.9MPG. or 19.02 km/l
7.55 liters = 1.99 gallon, 40 MPG, 16.96 km/l

Both very good!
yeah,
I was trying to do that in the middle of the night.... the stars must have been in my eyes :roll:
~John

'02 GL1800
2009 Piaggio MP3 250cc

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Alemayehu
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Location: Melbourne ,Australia
Motorcycle: 1992 Honda GL1500 SE
1983 Honda GL1100I Sold
1987 Honda GL1200I sold
1997 Honda GL1500A sold
1982 Honda CX500 Sold
1981 Honda CX500 Sold
1985 Honda GL650 Sold
1982 Honda GL400 Sold
1990 Yamaha XZ 400 Sold

Re: How can I resolve such fuel Consumption !

Post by Alemayehu »

Hi every one just updating you I have done a bit different riding style today following my mate sporty guy riding mostly at about 3000 rpm some times even more not much other wise the rest all round over 2750 rpm.I used 18.96 lt which is 5.01 us gallon and got 193.7 mile (311.73 km).
1 lt = 16.44 km ( 1 gallon / 38.74 mile) which is good.I have got very good lesson and now I know how it works out to get around 40 mile / gallon.
Thank you again it is getting colder here in Melbourne winter is on its way.

Thank you and God bless!
Jesus is Lord!

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CrystalPistol
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Re: How can I resolve such fuel Consumption !

Post by CrystalPistol »

CrystalPistol wrote:
Sat Mar 07, 2020 7:37 pm

I have kept my eye open for a brass 1/8" aquarium valve to insert in line.
Scratch that idea.
I just added a ball type fuel valve in place of where OEM fuel filter was, I have a bigger fuel filter elsewhere.


Make Courtesy your "Code of the Road" …

… & Have a Safe Trip!
:)

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