Slight RPM surge at idle


Information and questions on GL1500 Goldwings (1988-2000)
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702scottc
Posts: 252
Joined: Tue May 15, 2012 12:12 am
Location: Las Vegas, Nevada
Motorcycle: 1980 GL1100 Interstate (sold)
1990 GL1500 Aspencade (sold)
2005 GL1800

Slight RPM surge at idle

Postby 702scottc » Wed Mar 23, 2016 8:31 pm



Noticed this afternoon when I got home from work that the engine RPM would surge around 50 rpm's then settle then surge again. Never noticed this before.. I did stop on my way home last week and bought gas from a local supplier, not a major brand that I usually buy. Not sure if this is just a case of low quality fuel or something else. Anyone run into this before? Runs fine otherwise..



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WingAdmin
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Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Slight RPM surge at idle

Postby WingAdmin » Thu Mar 24, 2016 4:52 am

If the fresh tank of gas doesn't make a difference, you might have a vacuum leak, which is the most common cause of surging like this.

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Dusty Boots
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Location: Alvinston, SW ON
Motorcycle: 1992 GL1500Aspencade

Re: Slight RPM surge at idle

Postby Dusty Boots » Thu Mar 24, 2016 5:23 am

If it hasn't disappeared with a fresh tank of fuel, try this ....

Open your fuel access door and with the bike running, adjust the idle speed adjustment knob back and forth so it changes your idle speed up and down. It will be stiff to move.
Once you have done that a couple of times, set the idle speed to +/- 800 RPM and then blip the throttle a few times and let it come to a steady idle again. Turn off bike and then start it up again to check idle speed. Adjust as needed!



User avatar
702scottc
Posts: 252
Joined: Tue May 15, 2012 12:12 am
Location: Las Vegas, Nevada
Motorcycle: 1980 GL1100 Interstate (sold)
1990 GL1500 Aspencade (sold)
2005 GL1800

Re: Slight RPM surge at idle

Postby 702scottc » Thu Mar 24, 2016 9:44 am

Thanks for the input. A vacuum leak is what I've been thinking. It has been sputtering more over the last few days when it's cold. Going to take a ride with some friends tomorrow and I'll run 2 or 3 tanks of "good fuel" thru it and see what that does. I typically never use generic fuel but I forgot to stop the night before and the fuel light was glowing on the way home. Pushing isn't a fun thought..




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