GL1100 strange acceleration problem


Information and questions on GL1100 Goldwings (1980-1983)
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

GL1100 strange acceleration problem

Post by 77MM99 »



Hello all,

I have a GL1100 1980 and a couple of years ago an issue appeared: all of a sudden, during riding the engine got somewhat laggy, it accelerated and revved slower than before, it lost that “oomph” - mainly in lower revs between 2000-4000 RPM. The motorcycle at that time was stock, with stock exhausts, which were leaky and later rotted out completely. Nevertheless, even with those exhausts before then the motorcycle pulled really strong and ran great.

In hope to mend the issue the following things were replaced/serviced:
- aftermarket Marving exhausts
- carburettors overhauled with Keyster kit, whereas the 4 smaller pumps and the accelerator pump are new Honda OEM
- felts in carburettors replaced with custom ones
- carburettors synchronized
- ignition coils replaced (aftermarket)
- pulse generator replaced - NOS Honda OEM
- vacuum advance replaced - new Honda OEM
- mechanical ignition checked and greased – the pin was not worn out
- fuel pump replaced - new Honda OEM
- water pump and hoses replaced - new Honda OEM
- stator replaced (aftermarket)
- heads and valves were overhauled; gaskets, valve seats and seals - new Honda OEM
- valves were adjusted
- spark plugs replaced
- spark plug cables checked
- fuel tank cleaned of rust; fuel filter and hoses regularly replaced
- air filter replaced
- belts regularly changed – new Honda OEM
- the compression is equal on all four cylinders – about 150 psi
- oil in final drive changed, the final drive does not make any noise.

All of these things improved the performance considerably, however the issue is still persistent, although to a lesser extent. The motorcycle starts immediately every time, idles perfectly and at constant RPMs, does not stutter or sputter, neither at idle nor at acceleration and is throttle responsive. It backfires a little bit on higher revs when the throttle is completely closed, which I ascribe to aftermarket exhausts. It does not smoke whatsoever, not even at startup. It does not overheat, it does not consume or leak coolant. It burns a bit of oil, mostly when ridden for longer periods on highway when RPMs are constantly between 5500-6000 – regardless, it burned some oil even before the mentioned issue appeared. I’m using mineral 20W50 motorcycle oil. Fuel consumption is around 40 mpg. It has no problem reaching speeds of 100 mph.

TLDR version:
The weirdest thing is, that the issue is intermittent – it comes and goes. I usually do about 300 miles trips with a couple of stops for a coffee and lunch and it goes as follows:
- when I start the bike in the morning (overnight cold) – the bike runs perfectly, it pulls well in all RPM ranges, the engine runs smooth and the sound is normal
- after about half an hour or so the engine starts to sound a bit different (if normal acceleration sounds “VOOOM”, it starts to sound like “VRRROOM”; when the bike is running at constant revs it is sort of a buzzing sound like “BRRR” – I do not know how to describe it more accurately – but it is not an engine knocking noise or the chain rattle noise), it still runs on all 4 cylinders, however acceleration gets worse and laggy at lower revs, it feels and sounds as if the engine is struggling somewhat and does not seem to run that smooth; the takeoffs from standstill are not problematic and at revs over 4000 RPM the bike still pulls fairly OK – it just seems to lose some power and that “oomph” that I know the motorcycle is otherwise capable of
- now approximately on the second half of the trip the issue all of a sudden completely disappears, the engine sound is back to normal, the engine runs completely smooth, it pulls as strong as ever across the whole RPM range and it stays so for the rest of the trip.
It’s the same every time.

Does anyone have any clues what might be wrong? It would be greatly appreciated.

Thank you


77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

No one not even a clue? :/
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Rambozo
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Ducati Monster

Re: GL1100 strange acceleration problem

Post by Rambozo »

So far you have not provided much in the way of testing, and just thrown a bunch of parts at an unknown problem. That only makes things harder, as you may just as likely introduced new problems.
Does it do this on every extended ride, or will it be perfect for some rides?
What happens if you add choke when it is down on power?
Have you ever stopped when it wasn't running right and checked anything? Maybe pull the spark plugs to see how they look?
Can you make this happen or is it truly random?
Have you measured anything?
Have you cycled the kill switch when it was misbehaving? If so, do you get a backfire from that?

It sounds like a possible weak spark. I would check voltage at the coils both cold and hot. The first thing that comes to mind on a bike that old are dirty wiring connectors. Honda dielectric grease is well known to go bad over the years.
I am thinking it is a thermal issue as it takes some time to happen, then goes away once out of that zone.
But all this is just guessing without any real testing.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

Rambozo wrote: Sun Jun 18, 2023 4:48 am So far you have not provided much in the way of testing, and just thrown a bunch of parts at an unknown problem. That only makes things harder, as you may just as likely introduced new problems.
Does it do this on every extended ride, or will it be perfect for some rides?
What happens if you add choke when it is down on power?
Have you ever stopped when it wasn't running right and checked anything? Maybe pull the spark plugs to see how they look?
Can you make this happen or is it truly random?
Have you measured anything?
Have you cycled the kill switch when it was misbehaving? If so, do you get a backfire from that?

It sounds like a possible weak spark. I would check voltage at the coils both cold and hot. The first thing that comes to mind on a bike that old are dirty wiring connectors. Honda dielectric grease is well known to go bad over the years.
I am thinking it is a thermal issue as it takes some time to happen, then goes away once out of that zone.
But all this is just guessing without any real testing.
Hello,
thank you for the guidelines.

Yes, it does it on every extended ride, it is never perfect all the time - it happens every time in the same way as described, not randomly.

Adding choke does not affect it in any way, except that the idle rises to 3000 RPM.

I did not get backfire from cycling the kill switch - engine stopped for a moment then continued to run normally.

Yes, I have measured the coils when cold and when hot - there was no difference: primary resistance was 2,6 Ohm and 2,7 Ohm, secondary was 22.6 kOhm and 23.3 kOhm.

Plugs when cold:

Front right
Front right


Front left
Front left


Rear right
Rear right


Rear left
Rear left

The front ones look like it's overheating a bit?
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

The 1980 OEM carbs do not have removable emulsion tubes thus are very hard to know if these jets are plugged up - these are the mid range jets and all the jets work together to some degree so all really need to be clean.

I had a problem like yours and solved it by cleaning all the rust from the gas tank and cleaned the carbs again and the bike has run great for years. As a side note I rode it from Tampa, FL to Athens Tennessee today. The bike ran great but I don't care for the stock seat so much. :lol:

Anyway, on my 1983 GL1100 it took me about two years to sort the issue. I would clean the carbs and all was well then over time the problem would happen again and keep happening until I cleaned the carbs again and all would be well for 6 months or so and the issue would start all over. (Like your issue the bike would run fine some of the time and then get a bit sluggish and then might clean-up later in the same ride)

In my case, and this might not be your problem, rust from the gas tank would pass through the fuel filter and this is very very very fine rust - yet still heavier than gas so would collect in the bottom of the float bowl and turn into a solid chunk of solidified mud. This was not a problem until hitting a bad pot-hole which would break up the chunk sitting in the bottom of the float bowl and this would clog the tiny mid range jets.

I tried everything before I came to this solution. Coils, plug wires, brand new OEM fuel pump, removing the gas cap, and so on. (I put the old fuel pump back on and sold the new one to a friend)

You may want run most of the gas out of your bike and pull the fuel gauge sending unit under the seat and see if there is much rust in your tank....

The 1982 and 1983 carbs have a removable midrange jet that can be cleaned. Anyway, I don’t know if this is your issue but it’s worth confirming that you have a rust-free gas tank.

I now also run the stock fuel filter along with a 2nd unit after the fuel pump.

Again, your issue might be something else and that is why it's important to have several motorcycles 6 or 7 good ones will do - this way there is no urgency : )

Good Luck!
User avatar
winguyjo
Posts: 627
Joined: Sat Aug 11, 2018 9:26 pm
Location: b.c. Canada
Motorcycle: wing 8 : 1982 gl1100 standard.

Re: GL1100 strange acceleration problem

Post by winguyjo »

"Again, your issue might be something else and that is why it's important to have several motorcycles 6 or 7 good ones will do - this way there is no urgency : )"

best advice given since advice-giving began !
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

Thanks for the input!

The fuel tank was removed and was thoroughly cleaned of rust, but will check again just to make sure. The carbs have been ultrasonically cleaned a couple of times - the last time they were taken apart, they were checked for rust and there was none in the float bowls.

The issue doesn't seem to be getting worse over time (i.e. in a period of 6 months as you have suggested), it's just pretty much the same all the time.
PhotoDoctor wrote: Sat Jul 01, 2023 6:20 pm The 1980 OEM carbs do not have removable emulsion tubes thus are very hard to know if these jets are plugged up - these are the mid range jets and all the jets work together to some degree so all really need to be clean.

I had a problem like yours and solved it by cleaning all the rust from the gas tank and cleaned the carbs again and the bike has run great for years. As a side note I rode it from Tampa, FL to Athens Tennessee today. The bike ran great but I don't care for the stock seat so much. :lol:

Anyway, on my 1983 GL1100 it took me about two years to sort the issue. I would clean the carbs and all was well then over time the problem would happen again and keep happening until I cleaned the carbs again and all would be well for 6 months or so and the issue would start all over. (Like your issue the bike would run fine some of the time and then get a bit sluggish and then might clean-up later in the same ride)

In my case, and this might not be your problem, rust from the gas tank would pass through the fuel filter and this is very very very fine rust - yet still heavier than gas so would collect in the bottom of the float bowl and turn into a solid chunk of solidified mud. This was not a problem until hitting a bad pot-hole which would break up the chunk sitting in the bottom of the float bowl and this would clog the tiny mid range jets.

I tried everything before I came to this solution. Coils, plug wires, brand new OEM fuel pump, removing the gas cap, and so on. (I put the old fuel pump back on and sold the new one to a friend)

You may want run most of the gas out of your bike and pull the fuel gauge sending unit under the seat and see if there is much rust in your tank....

The 1982 and 1983 carbs have a removable midrange jet that can be cleaned. Anyway, I don’t know if this is your issue but it’s worth confirming that you have a rust-free gas tank.

I now also run the stock fuel filter along with a 2nd unit after the fuel pump.

Again, your issue might be something else and that is why it's important to have several motorcycles 6 or 7 good ones will do - this way there is no urgency : )

Good Luck!
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

I have also measured the temperature of the cylinders with a laser thermometer and the values for all four cylinders were without noticeable deviations, save for a couple of +/- degrees C.
Rambozo wrote: Sun Jun 18, 2023 4:48 am So far you have not provided much in the way of testing, and just thrown a bunch of parts at an unknown problem. That only makes things harder, as you may just as likely introduced new problems.
Does it do this on every extended ride, or will it be perfect for some rides?
What happens if you add choke when it is down on power?
Have you ever stopped when it wasn't running right and checked anything? Maybe pull the spark plugs to see how they look?
Can you make this happen or is it truly random?
Have you measured anything?
Have you cycled the kill switch when it was misbehaving? If so, do you get a backfire from that?

It sounds like a possible weak spark. I would check voltage at the coils both cold and hot. The first thing that comes to mind on a bike that old are dirty wiring connectors. Honda dielectric grease is well known to go bad over the years.
I am thinking it is a thermal issue as it takes some time to happen, then goes away once out of that zone.
But all this is just guessing without any real testing.
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

As a side note, Honda made the gas mix very lean in 1980's as show by your spark plug photos.

If it were me, and it's not, I would be keeping a look out for a good rebuildable set of carbs from a 1982 or 1983 with the removable emulsion tubes - aka the mid range jets.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Thu Jul 06, 2023 6:53 am As a side note, Honda made the gas mix very lean in 1980's as show by your spark plug photos.

If it were me, and it's not, I would be keeping a look out for a good rebuildable set of carbs from a 1982 or 1983 with the removable emulsion tubes - aka the mid range jets.
So you'd say even the front two plugs seem fairly normal?
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

All the plugs look like they are on the lean side, very white vs. a tan look that is considered more normal in motors.

I believe Honda did this to help pass emission test in some states like California. Some of my friend's re-jet their 1980's bikes so their plugs are not so Bone White and lean which improves the mid-range and takes the flat spots out of the acceleration.

On another note we had Leaded gas in 1980 and the speed limit was 55 mph.

My money would be on a fuel delivery for the issues you have, and a bit richer in the mid-range jets would help.
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Overdog
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Location: Pittsburgh, Pennsylvania
Motorcycle: 83 Goldwing Interstate

Re: GL1100 strange acceleration problem

Post by Overdog »

You say you replaced the accelerator pump. Did you physically check that all the nozzles are squirting?
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Thu Jul 06, 2023 7:33 am All the plugs look like they are on the lean side, very white vs. a tan look that is considered more normal in motors.

I believe Honda did this to help pass emission test in some states like California. Some of my friend's re-jet their 1980's bikes so their plugs are not so Bone White and lean which improves the mid-range and takes the flat spots out of the acceleration.

On another note we had Leaded gas in 1980 and the speed limit was 55 mph.

My money would be on a fuel delivery for the issues you have, and a bit richer in the mid-range jets would help.
Raising (shimming) the needles, especially on the front two carbs would probably help, correct?
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

My money is on your midrange jets being blocked. Reading your first post - the bike use to run fine with the needles where they are.

However, raising the needles might help.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Mon Jul 10, 2023 9:18 pm My money is on your midrange jets being blocked. Reading your first post - the bike use to run fine with the needles where they are.

However, raising the needles might help.
Valid point. Although the mid-range jets are non-removable in the early type GL1100 carbs, they were removed at the workshop and were cleaned.
Raising the needles would at least make the bike run less hot for now - until the possible jet issue is solved.
Last edited by 77MM99 on Tue Jul 11, 2023 7:18 am, edited 1 time in total.
77MM99
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Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

Overdog wrote: Sat Jul 08, 2023 9:14 pm You say you replaced the accelerator pump. Did you physically check that all the nozzles are squirting?
This was done at the workshop - it was checked and said to be functioning properly.
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

The "Work Shop" sounds interesting - I'd like to know more about that and any future ones. I guess I'd better look at this forum more often.

Yes, raising the needles may help.

You may also keep your eyes out for another set of carbs for the 82, 83 models that are in good shape to go through.

Do you do your own work, or send it out?
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Tue Jul 11, 2023 7:53 am The "Work Shop" sounds interesting - I'd like to know more about that and any future ones. I guess I'd better look at this forum more often.

Yes, raising the needles may help.

You may also keep your eyes out for another set of carbs for the 82, 83 models that are in good shape to go through.

Do you do your own work, or send it out?
What I meant was that the work was done by a professional mechanic.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Tue Jul 11, 2023 7:53 am The "Work Shop" sounds interesting - I'd like to know more about that and any future ones. I guess I'd better look at this forum more often.

Yes, raising the needles may help.

You may also keep your eyes out for another set of carbs for the 82, 83 models that are in good shape to go through.

Do you do your own work, or send it out?
Would it be preferable to acquire the full set of '82/'83 carbs (including plenum, linkages...) or would the carbs only suffice and I could utilize the existing plenum, brackets, linkages... ?
Thanks for everything
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

I would take my time and find a good set that is all together and I would also remove at least one float bowl and see what the inside looks like.

However, this is a tough call if you are not sure what to look for.

((You don't want to take your original set all apart and off the manifold and risk not having a set that works at all - at least now you can ride the bike ))



I believe there are a few shops in the country that specialized in the older 4 banger Goldwings and may offer carb service. I don't think it would be a great idea to use anyone that doesn't specialize in the older Goldwings.

Do you do any of the work yourself such as remove the carbs from the bike or do you have a shop do it all?

Now I'm curious and will have to look at shops that specialize in the older Goldwings - I'll see what I can find or maybe someone here already has a list.

Randsaks comes to mind.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Tue Jul 11, 2023 10:58 am I would take my time and find a good set that is all together and I would also remove at least one float bowl and see what the inside looks like.

However, this is a tough call if you are not sure what to look for.

((You don't want to take your original set all apart and off the manifold and risk not having a set that works at all - at least now you can ride the bike ))



I believe there are a few shops in the country that specialized in the older 4 banger Goldwings and may offer carb service. I don't think it would be a great idea to use anyone that doesn't specialize in the older Goldwings.

Do you do any of the work yourself such as remove the carbs from the bike or do you have a shop do it all?

Now I'm curious and will have to look at shops that specialize in the older Goldwings - I'll see what I can find or maybe someone here already has a list.

Randsaks comes to mind.
So far I've had it mostly done at the shop, however I plan to remove the carbs myself at least to raise the needles and then see what happens.
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

That's a good idea and it can be done without removing the gas tank. There are some videos on youtube that will help. It's a process - after taking all 4 intake boots off - you can move the carbs to the right and take the tops off. Then you have to slide and wiggle them out the left side of the frame.

There may be some info on this site as well. It sounds like a winter time job for you as you won't be riding much then anyway : )
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Tue Jul 11, 2023 12:29 pm That's a good idea and it can be done without removing the gas tank. There are some videos on youtube that will help. It's a process - after taking all 4 intake boots off - you can move the carbs to the right and take the tops off. Then you have to slide and wiggle them out the left side of the frame.

There may be some info on this site as well. It sounds like a winter time job for you as you won't be riding much then anyway : )
Uhmm a winter project? :) I plan on doing it this Saturday :D It shouldn't really take more than an afternoon, should it?

Yes, thanks, I've already checked some info on how to do it. I believe I don't have to unplug any of the hoses or cables, do I? Just as you suggested I planned on moving the carbs an inch or so to the right and left to give me sufficient space to remove the tops and get access to the needle.

However not removing the gas tank? Don't I have to remove the air filter assembly just to get the carbs to wiggle left and right?

At first I planned to raise only the front two needles for about 0,5 mm - 1 mm (more like 1 mm) since the front two cylinders seemed quite hot - or should I raise all four? I am aware that this is a trial-and-error process so I will probably have to do it a couple of times.

When I put everything back together should I pay special to anything?

The intake manifold o-rings are reusable, correct?
PhotoDoctor
Posts: 110
Joined: Mon Apr 06, 2015 7:31 pm
Location: Tampa, FL
Motorcycle: 1982 GL1100 Standard and several GL650s , few GL500s

Re: GL1100 strange acceleration problem

Post by PhotoDoctor »

Yes, you can do that in a few hours. The rubber boots will be very stiff so a hair dryer or heat gun may help get them back on along with some silicone spray.

You will have to remove the air-filter to move the carbs left and right, but that's no big issue.

The o-rings are reusable if they don't break - you may want some black RTV as a backup or to also hold in place when you put it back together.

Good luck - and be careful to use a good fitting screw driver so as not to strip any screws.
77MM99
Posts: 22
Joined: Sat Jan 09, 2021 4:55 pm
Location: New York
Motorcycle: 1980 GL1100 Standard

Re: GL1100 strange acceleration problem

Post by 77MM99 »

PhotoDoctor wrote: Tue Jul 11, 2023 4:02 pm Yes, you can do that in a few hours. The rubber boots will be very stiff so a hair dryer or heat gun may help get them back on along with some silicone spray.

You will have to remove the air-filter to move the carbs left and right, but that's no big issue.

The o-rings are reusable if they don't break - you may want some black RTV as a backup or to also hold in place when you put it back together.

Good luck - and be careful to use a good fitting screw driver so as not to strip any screws.
Why would I need to remove the rubber boots? Can't I just raise the carbs a bit and pull them a little to one side and the other so the tops can be removed? Or maybe twist them a bit?


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