1988 hard start,surging idle after fuel additive


Information and questions on GL1500 Goldwings (1988-2000)
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zamboni920
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Location: Stavanger, Norway
Motorcycle: 1996 GL1500 SE with Hannigan 2+2 sidecar

1988 hard start,surging idle after fuel additive

Postby zamboni920 » Sat May 12, 2012 1:47 pm



After I removed the cozy mousenest (sorry, mice) on top of the airfilter, my 1988 GL1500 Interstate idled quite nice indeed. A little hesitation, but otherwise beautiful idle and nice responsive throttle. I figured it might be a good idea to add some Seafoam to the tank, maybe it will clean out the rest of the carb passages. Well, I added the seafoam, about 1/2 pint to nearly full tank. Now it seems a lot worse. It is very hard to start.....at times the battery slows down before it starts, and I have to charge it. I also notice some "puffing" , almost like backfire, as it tries to fire. When it does start, I have to work the throttle and the choke to keep it running until it warms up. Could the Seafoam have loosened particles, wich now are clogging parts of the carb? I think Seafoam states it will not damage any internal parts. Would it be worth wasting the tank, drain and refill? If so, what is the easiest way to drain this tank? I did replace the "mousy" K&N airfilter with an OEM from Honda, but the issue was present both before and after this.
Of course, the issue could be something entirely different, but it would be an odd coincident.



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virgilmobile
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Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 1988 hard start,surging idle after fuel additive

Postby virgilmobile » Sat May 12, 2012 2:20 pm

Have a read on these posts.One is my 88.
http://www.goldwingdocs.com/forum/viewt ... f=6&t=9804
http://www.goldwingdocs.com/forum/viewt ... =6&t=10376
http://www.goldwingdocs.com/forum/viewt ... f=6&t=5741
viewtopic.php?f=6&t=7824
And many more.
Usually associated with vacuum lines weak at the tight 90* bend.Start on the manifold,2 on each side.

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zamboni920
Posts: 250
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Location: Stavanger, Norway
Motorcycle: 1996 GL1500 SE with Hannigan 2+2 sidecar

Re: 1988 hard start,surging idle after fuel additive

Postby zamboni920 » Sat May 12, 2012 2:47 pm

Thanks Virgil....I see some vacuum leak chasing coming on. It would be strange that this seemed to happen exactly at the same time I added Seafoam though. Could the Seafoam possibly damage an already weak vacuum hose?
I might, at some point , rebuild the carbs. There are kits available, but is there any particular brands that are better than others? Also, I think I read somewhere that the early GL1500 were typically rejetted with slightly larger jets/needles during a rebuild?

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robb
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Motorcycle: 1989 Honda GL1500 Aspencade

Re: 1988 hard start,surging idle after fuel additive

Postby robb » Sun May 13, 2012 9:34 am

Four ounces sea foam to a tank of fuel will make my 89 run like crap every time.

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zamboni920
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Joined: Sun Aug 14, 2011 5:15 am
Location: Stavanger, Norway
Motorcycle: 1996 GL1500 SE with Hannigan 2+2 sidecar

Re: 1988 hard start,surging idle after fuel additive

Postby zamboni920 » Sun May 13, 2012 9:13 pm

Well, it seems the problem is solved....although I won't feel sure until I've tested it for a few days. What I did was.....just about nothing. I was ready to dig into carburator vacuums, but before I got too far I figured I'll point some carb cleaner in direction of the carbs without removing more than the side covers and "carb covers"(?) . The idea was to see if there was any change in RPM's. No change was noticable regardless of wich parts I tried to (blindly) aim at.
As I was doing this, I decided to spray some around the Auto Shutoff Valve , just for the hell of it. I noticed immediately a hissing sound, and "popping" in the exhaust. " I am onto something" I thought. Closer inspection revealed that the small vacuum hose that connects to this valve, sucks air from a tiny hole at the bottom of the valve. This is generally a hidden, but dirty , area, and apparently the dirt also gets sucked in. I removed the mounting bracket(the tiny hole is behind it) and sprayed carb cleaner into the hole until it came out through the hose connector. Also a little into the hose itself to loosen any dirt that got that far. Very simple to do, and it cleared the idle and the starting issue perfectly.For now .
Robb.....I think I'll run this tank low and forget about any more Seafoam.
As I was working I decided to steal Wingadm's idea and put on the intake screen. Thanks Wingadm !!



Read more: viewtopic.php?f=6&t=10558#ixzz1uo283SCr
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virgilmobile
Posts: 7653
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 1988 hard start,surging idle after fuel additive

Postby virgilmobile » Mon May 14, 2012 7:19 am

So I get the impression you did find a leak.The vacuum fuel cutoff valve.It has 2 diaphragms,One on the fuel side,one on the vacuum side.the hole in the casting bottom it to vent the pressure when the valve is operated and should not be open to the fuel or vacuum line.That vacuum line goes to the right intake manifold.Obviously a leaking air diaphragm may still operate the valve OK but suck air into the manifold.If your problem persists,bypass the valve and plug the line till a replacement valve can be installed.

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zamboni920
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Location: Stavanger, Norway
Motorcycle: 1996 GL1500 SE with Hannigan 2+2 sidecar

Re: 1988 hard start,surging idle after fuel additive

Postby zamboni920 » Mon May 14, 2012 4:01 pm

Virgil....thanks. I really had no idea what that vacuum/vent line was for....now I know. I will keep your advice in mind, and maybe order a new cut-off valve anyway, after all, it is 24 years old. I started it up after work today, and even with cold engine, it started much,much easier than before, and the idle settled nicely to just under 1000RPM's. Throttle response was also nice, even cold.
Right now, it makes me think of all the "newbies" in the motorcycle world who generally have no idea what is involved when buying an older bike. The Goldwing, any model, is quite a complicated bike for it's year( after all, even in 1975, the Goldwing was an innovation of proportion by Honda) , and the older it is , the more maintenance, upkeep and repairs will it likely need.

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virgilmobile
Posts: 7653
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: 1988 hard start,surging idle after fuel additive

Postby virgilmobile » Tue May 15, 2012 9:39 am

I'm looking for a rebuild kit for mine.The casting is OK just the diagram has a pin hole in the fuel side.In the meantime I've put on a electric valve,but having a spare is a good idea.




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