Hey all, I just picked up a GL1500 this weekend. Beautiful bike, only problem with it is that it has an idle surge (about 800-1200rpm) and will occasionally stick around 2100rpm. I figure the idle surging stuff is vacuum leak related based on reading around the forum. However, what's really stumping me is what's causing that throttle to stick? If I'm slowing down, it won't want to drop down below 2100rpm. I have to pull the clutch in at that point or it wont slow down. Sometimes, downshifting to 2nd or 1st will free it up. Blipping the throttle sometimes frees it also. Doesn't feel like the slide is sticking, I still have full throttle rotation without binding (it also will snap back to closed at any position). Could this also be vacuum related?
All I've done so far is ran a heavy dose of seafoam though the fuel tank. Doesn't seem like it did anything. I could keep doing that, some say that it takes a while to clear it all out using seafoam.
Any help would be greatly appreciated!
GL1500 Idle Surge and High Idle
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DandruffCat
- Posts: 13
- Joined: Sat Dec 03, 2022 12:25 pm
- Location: Murfreesboro, TN
- Motorcycle: 1989 GL1500
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DandruffCat
- Posts: 13
- Joined: Sat Dec 03, 2022 12:25 pm
- Location: Murfreesboro, TN
- Motorcycle: 1989 GL1500
Re: GL1500 Idle Surge and High Idle
Never miss a video: Subscribe to the GoldwingDocs YouTube channel today!
Link to the idling.
Events in the video: Idling -> Me revving to above 2100rpm, then releasing throttle -> Revs stabilize around 2100rpm -> Blipping the throttle to break the high idle -> Idle surging
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blupupher
- Posts: 786
- Joined: Sun May 17, 2020 5:47 pm
- Location: Katy, Republic of Texas
- Motorcycle: 2013 BMW K1600GT
Re: GL1500 Idle Surge and High Idle
Vacuum leak for the surging for sure, and could be the cause of the hanging revs as well, but could also be the throttle cables or something internal to the carbs.
Current ride: 2013 BMW K1600GT
Former rides: 2002 GL1800A, 2001 CB750, 1994 GL1500 SE, 1994 VT1100C , 1984 VF500F, 1982 CB750C, 1982 GS250T, 1981 CB900C, 1978 CB125s, 1976 TS185
Former rides: 2002 GL1800A, 2001 CB750, 1994 GL1500 SE, 1994 VT1100C , 1984 VF500F, 1982 CB750C, 1982 GS250T, 1981 CB900C, 1978 CB125s, 1976 TS185
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klppdx70
- Posts: 20
- Joined: Tue May 04, 2021 9:48 am
- Location: Portland, OR
- Motorcycle: 1995 GL1500 Interstate
2020 Triumph Speed Twin
Re: GL1500 Idle Surge and High Idle
Having just pulled the carbs on my 'new to me' '95 Interstate, replacing the carb isolators and 90 degree angle vacuum line 17173-MN5-000 on the left side under the heat mat, I agree with this assessment. My symptoms were similar to yours. In my case the carbs were fine, but the previous owner had apparently pulled them previously and let's just say did not follow the manual during re-installation of the vacuum lines. I recommend inspection of the lines themselves as well as verifying correct routing. Throttle cables at the carbs also a distinct possibility. Good luck with the project.