how to access air/fuel mixture screw (s) ??


Information and questions on GL1500 Goldwings (1988-2000)
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ryan1980
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Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

how to access air/fuel mixture screw (s) ??

Post by ryan1980 »



hi all, finally got my gl1500 back together and running.

It's backfiring under load :( Perhaps too lean? It runs well otherwise!

I would like to know how to access the air / fuel mixture screws - which panels do i need to remove ??

Ryan


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newday777
Posts: 2153
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Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: how to access air/fuel mixture screw (s) ??

Post by newday777 »

Do you have the service manual for the bike? It tells you how and where the air adjustment is made. Do you have the "D" socket adjustment tool to adjust the air pilot screws before you try?

We don't know what you've been doing in your "finally got my bike back together and running"
You have to fill in the blanks to what you are doing so we might know if you left something unplugged in your doings.....
ryan1980
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Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

Re: how to access air/fuel mixture screw (s) ??

Post by ryan1980 »

I do have a Haynes workshop manual but it doesn’t specify how to access the adjustment . I have been repairing an accident damaged bike which appeared to me to be running fine (although i have not been able to ride it until today).

The backfiring happens under load , the bike doesn’t appear to miss and otherwise runs well . I thought maybe the mixture is a touch lean .
ryan1980
Posts: 9
Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

Re: how to access air/fuel mixture screw (s) ??

Post by ryan1980 »

I haven’t done any mechanical work to the bike as I wasn’t aware of any issues until today. I’m unsure of what the previous owner has done .
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newday777
Posts: 2153
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: how to access air/fuel mixture screw (s) ??

Post by newday777 »

ryan1980 wrote: Mon Dec 21, 2020 8:33 am I do have a Haynes workshop manual but it doesn’t specify how to access the adjustment . I have been repairing an accident damaged bike which appeared to me to be running fine (although i have not been able to ride it until today).

The backfiring happens under load , the bike doesn’t appear to miss and otherwise runs well . I thought maybe the mixture is a touch lean .
Explain where it is backfiring and what exactly it is .
That doesn't fit with "doesn't appear to miss and otherwise runs well"

Through the exhaust??
The carbs??
Loud bang????
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terryt
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1989 gl1500 trike
1995 Kawasaki gt550 Trike

Re: how to access air/fuel mixture screw (s) ??

Post by terryt »

newday777 wrote: Mon Dec 21, 2020 7:35 am Do you have the service manual for the bike? It tells you how and where the air adjustment is made. Do you have the "D" socket adjustment tool to adjust the air pilot screws before you try?

We don't know what you've been doing in your "finally got my bike back together and running"
You have to fill in the blanks to what you are doing so we might know if you left something unplugged in your doings.....
D socket tool. I used a long flat blade on mine. D socket is used on the Valkyrie six carbs
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DenverWinger
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1980 GL1100 STD Vetter (2005-)
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1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
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Re: how to access air/fuel mixture screw (s) ??

Post by DenverWinger »

Though unlikely if it's otherwise running well, you might double-check there's not a couple sparkplug wires got crossed by the PO, a common cause of backfiring, sometimes "smooth-running" can fool ya. Might be a simple fix!
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
ryan1980
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Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

Re: how to access air/fuel mixture screw (s) ??

Post by ryan1980 »

It's not really a loud banging noise, it's more of a popping , i believe through the carb.

I will double check the plugs :)

I do appreciate all the advise, however if someone could tell me how to access the adjustment , where it's located? Which panels i need to remove??
ryan1980
Posts: 9
Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

Re: how to access air/fuel mixture screw (s) ??

Post by ryan1980 »

terryt wrote: Mon Dec 21, 2020 8:53 am
newday777 wrote: Mon Dec 21, 2020 7:35 am Do you have the service manual for the bike? It tells you how and where the air adjustment is made. Do you have the "D" socket adjustment tool to adjust the air pilot screws before you try?

We don't know what you've been doing in your "finally got my bike back together and running"
You have to fill in the blanks to what you are doing so we might know if you left something unplugged in your doings.....
D socket tool. I used a long flat blade on mine. D socket is used on the Valkyrie six carbs
where is the adjustment , how do i access it? which panels to remove?
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newday777
Posts: 2153
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: how to access air/fuel mixture screw (s) ??

Post by newday777 »

terryt wrote: Mon Dec 21, 2020 8:53 am
newday777 wrote: Mon Dec 21, 2020 7:35 am Do you have the service manual for the bike? It tells you how and where the air adjustment is made. Do you have the "D" socket adjustment tool to adjust the air pilot screws before you try?

We don't know what you've been doing in your "finally got my bike back together and running"
You have to fill in the blanks to what you are doing so we might know if you left something unplugged in your doings.....
D socket tool. I used a long flat blade on mine. D socket is used on the Valkyrie six carbs
No. The D socket is used on the gl1500 goldwing.
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Snowmoer
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Re: how to access air/fuel mixture screw (s) ??

Post by Snowmoer »

newday777 wrote: Mon Dec 21, 2020 9:37 am
terryt wrote: Mon Dec 21, 2020 8:53 am
newday777 wrote: Mon Dec 21, 2020 7:35 am Do you have the service manual for the bike? It tells you how and where the air adjustment is made. Do you have the "D" socket adjustment tool to adjust the air pilot screws before you try?

We don't know what you've been doing in your "finally got my bike back together and running"
You have to fill in the blanks to what you are doing so we might know if you left something unplugged in your doings.....
D socket tool. I used a long flat blade on mine. D socket is used on the Valkyrie six carbs
No. The D socket is used on the gl1500 goldwing.
I also used just a long flat blade screw driver on mine. You access the screws between the top of the screen that protects the radiators and the just below the brace for the faring. You will need a flashlight to see them. They can be a little bit of a pain to find. No need to remove any plastic. At least that was how it was on my 88.

My 88 had a popping/backfire sound in warmer weather at idle. Balancing the carbs helped a lot, but it still would do it at times. I also adjusted the air screws because it had a strong exhaust smell that was like it was running rich. Never could get the popping to totally stop, or the exhaust smell. Sold the bike, so I don't have to worry about it anymore!
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newday777
Posts: 2153
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: how to access air/fuel mixture screw (s) ??

Post by newday777 »

Deceleration popping is normal and not usually heard with stock exhaust. Aftermarket mufflers and deletion of the collector box will make it noticed more.
ryan1980
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Joined: Wed Nov 11, 2020 5:32 am
Location: perth, western australia
Motorcycle: 1995 GL1500

Re: how to access air/fuel mixture screw (s) ??

Post by ryan1980 »

thanks for the info :) I read somewhere else that the mixture screws were accessed through the side panels on the bike, i didnt think that sounded right!

I should of specified, the popping is when accelerating, under load...
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ct1500
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Re: how to access air/fuel mixture screw (s) ??

Post by ct1500 »

The '88 machines did use a slotted head mixture screw where a regular flat driver would work. Not sure on the '89 model because that is one of the few years that has not run through my shop. '90 and up models all use the "D" bit for adjustment.
The manual states to access through the recess hole above the radiator, good luck with that and is really a no go due to ignition wires from the coils blocking the way along with not being able to get a visual of your bit and mixture screws. Way more hassle than it is worth.
A D bit tool is required and I can use both of these on a GW. The bit can be purchased separately.
https://www.motionpro.com/product/08-0229
https://redeye.ecrater.com/p/20824302/h ... ew-tool-on
Top shelter, inner fairings and air box are always off when I adjust them because it is along with carburetor or tune-up work etc. being done. They are in a tough location to access at the front very lower of carbs and you won't find them without the aid of an inspection mirror.
If the mixture screw(s) were lean enough to cause popping it more than likely would be idling poorly. The popping when throttling above 1500 RPM's is more likely a problem with the main jets, secondary mains (slides), fuel delivery or ignition issues.
Local and need repair help with your 1500, Valkyrie or ST please click contact
Nothing leaves my shop till its' perfect
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Elmobile
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Re: how to access air/fuel mixture screw (s) ??

Post by Elmobile »

With Christmas around the corner, I was considering getting this Motion tool? I have tried using a LONG screw driver with a D bit but as CT1500 indicated: Forget it...

I am going to take the carbs out to clean them in an ultrasonic bath so it is done right this time. When doing the adjustment, you are looking for a very small rpm change (+/- 50). What kind of equipment if any do you use to measure this or do you do it by hear? Are you using a short D bit or the extended one?

Would appreciate your input as to what I need to get...
Happy holidays.


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