GL 1500 has a high idle but only sometimes


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Swayze
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Motorcycle: 1991 gl1500 interstate

GL 1500 has a high idle but only sometimes

Post by Swayze »



Hi all. I bought my first goldwing last summer. It's a 91 interstate. Serial #000001. Anyway I found when riding if I came to a stop it would sometimes idle high ( around 2000 rpm ). But only sometimes. I would guess around 25% of the time. Bike runs perfect otherwise. Any ideas? Thanks.


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offcenter
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Re: GL 1500 has a high idle but only sometimes

Post by offcenter »

Mine would do that "occasionally", when the outside temps were below 40 degrees.
Never does it in warm weather.
Damned if I know what causes it.
But since I rarely ride when temps are below 40, it hasn't really been
a problem.
George in Jersey.
99 Goldwing GL-1500 SE
76 Goldwing Gl-1000
77 Honda CT-90 "Trail 90"
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MikeB
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Re: GL 1500 has a high idle but only sometimes

Post by MikeB »

My first thought is that you have an intermittent vacuum leak. Cracked and deteriorating vacuum hoses could be the cause.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
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Swayze
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Motorcycle: 1991 gl1500 interstate

Re: GL 1500 has a high idle but only sometimes

Post by Swayze »

Ok I will look for that. Thanks
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ct1500
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Re: GL 1500 has a high idle but only sometimes

Post by ct1500 »

Swayze wrote: Mon Feb 22, 2021 1:32 pm Hi all. I bought my first goldwing last summer. It's a 91 interstate. Serial #000001. Anyway I found when riding if I came to a stop it would sometimes idle high ( around 2000 rpm ). But only sometimes. I would guess around 25% of the time. Bike runs perfect otherwise. Any ideas? Thanks.
Absent a binding throttle cable and to a lesser extent enrichment cable the most likely cause would be from a carb sync problem where it was adjusted compensating for a carb problem.
If I had a dollar for every poster who said "other than this problem it runs great" I would be comfortably retired. :) When an engine does not run right there is always a shortfall.
Local and need repair help with your 1500, Valkyrie or ST please click contact
Nothing leaves my shop till its' perfect
This is what I do
Swayze
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Motorcycle: 1991 gl1500 interstate

Re: GL 1500 has a high idle but only sometimes

Post by Swayze »

Can I get to all the vacum lines by removing the top plastic and air filter? Thanks
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bellboy40
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Re: GL 1500 has a high idle but only sometimes

Post by bellboy40 »

No. There are some under the air filter housing, some under the carbs and some more under the rubber mat below the carbs.
Swayze
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Re: GL 1500 has a high idle but only sometimes

Post by Swayze »

Crap that's not what I wanted to hear
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WingAdmin
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Re: GL 1500 has a high idle but only sometimes

Post by WingAdmin »

The vacuum hose routing is pretty much spaghetti. It's buried, and it's extensive.

Vacuum hose routing
Vacuum hose routing

robertmcmahon
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Motorcycle: 1999 Goldwing trike conversion,17k miles.

Re: GL 1500 has a high idle but only sometimes

Post by robertmcmahon »

bellboy40 wrote: Wed Mar 03, 2021 4:56 pm No. There are some under the air filter housing, some under the carbs and some more under the rubber mat below the carbs.
What is the rubber mat you are referring to? When I got my GL1500, 1999 trike it had a piece of rubber underneath the carburetors that looked like an inner tube? It was removed.
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bellboy40
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Re: GL 1500 has a high idle but only sometimes

Post by bellboy40 »

That rubber mat under the carbs is there to control heat from rising up to the manifold, rubber hoses and wires above the engine. That much heat would shorten the life of the hoses and wires. It also helps keep the fuel from getting vapor lock and keeps some of the engine heat off the rider. If yours is missing, I would suggest you replace it.
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Re: GL 1500 has a high idle but only sometimes

Post by robertmcmahon »

Thank you Bellboy40 that’s kinda what I thought. Can I still get the correct part from Honda? Or cut up an old inter tube. My carbs need major attention. You rebuild if I send them to you? I live in East Tennessee.
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bellboy40
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Re: GL 1500 has a high idle but only sometimes

Post by bellboy40 »

Here is the part# for that rubber mat. It is rather expensive for what it is but that's the way it is with motorcycle parts. I don't know how well a truck inner tube would work in that role but I suspect it would deteriorate rather quickly.
19050-MT2-010
Here is a couple of places to get it. They are the cheapest I found but I have never ordered anything from either of them. A search for that part# will show a lot of different places to get it.
http://www.adeptpowersports.com/oem-par ... -part.html

https://www.hondapartsnation.com/oempar ... water-pipe

To your question about rebuilding carbs, no I don't do that for others. I'm doing good just trying to keep my own motorcycle going! 😉
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WingAdmin
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Re: GL 1500 has a high idle but only sometimes

Post by WingAdmin »

bellboy40 wrote: Sat Oct 23, 2021 8:44 am Here is the part# for that rubber mat. It is rather expensive for what it is but that's the way it is with motorcycle parts. I don't know how well a truck inner tube would work in that role but I suspect it would deteriorate rather quickly.
19050-MT2-010
Here is a couple of places to get it. They are the cheapest I found but I have never ordered anything from either of them. A search for that part# will show a lot of different places to get it.
http://www.adeptpowersports.com/oem-par ... -part.html

https://www.hondapartsnation.com/oempar ... water-pipe

To your question about rebuilding carbs, no I don't do that for others. I'm doing good just trying to keep my own motorcycle going! 😉
Regular rubber like an inner tube will very quickly deteriorate, harden and crack under the heat it is subjected to there.

If you are going to do a DIY replacement then use some high-temperature silicone rubber sheeting, like this: https://www.amazon.com/Silicone-12x12-i ... ref=sr_1_4


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