bike idles fine but dies with throttle input??????


Information and questions on GL1200 Goldwings (1984-1987)
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b67
Posts: 4
Joined: Sat Sep 03, 2011 9:35 pm
Location: San Francisco, California
Motorcycle: 1986 GL1200 Interstate

bike idles fine but dies with throttle input??????

Postby b67 » Tue Sep 06, 2011 10:42 am



we have an 87 gl1200. it sat for a few years and then would not idel without the choke most of the way on. we drained the bowls, ran sea foam through it and got it to at least not die when we gave it throttle but it still would not idle without the choke. we took the carbs out and found some of the slow jets were clogged so we cleaned those and checked all the mains and floats. all looks really good. put it all back together and started it up. now it idles fine but when we add throttle it back fires and wants to die almost like its flooding out. is that a vacuum thing?

i've searched several threads but no luck. any thoughts or advice are greatly appreciated.

thanks fellas



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virgilmobile
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Re: bike idles fine but dies with throttle input??????

Postby virgilmobile » Tue Sep 06, 2011 11:27 am

Where does it back fire? Carbs or exhaust.
Carbs=lean. Exhaust=rich

b67
Posts: 4
Joined: Sat Sep 03, 2011 9:35 pm
Location: San Francisco, California
Motorcycle: 1986 GL1200 Interstate

Re: bike idles fine but dies with throttle input??????

Postby b67 » Tue Sep 06, 2011 5:48 pm

Backfires thru the carbs. I could see puffs of smoke coming out the plenum when the air filter was still off.

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virgilmobile
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83 GL1100 I
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84 GL 1200 I

Re: bike idles fine but dies with throttle input??????

Postby virgilmobile » Wed Sep 07, 2011 4:15 pm

Generally speaking...Carb back fire is related to 3 possibilities.
First question.Did it rev up OK before you worked on the carbs and just not idle?
If it did,then the valves are probably OK and the carbs or timing is suspect.
If it hasn't ,then the things to check are...

The vacuum part is a 1/8" hose connecting the carb to the ECU.It goes into a "T" connector then into the ECU box.Check for a unhooked hose on the left carb.

1.Slide or slide stuck in the carb.They must move up and down freely.


2.Ignition timing.

3.Valve timing.One tooth off on either belt will change the engine scavenge angle.The point where both the intake and exhaust valves are open.Sometimes called valve overlap.

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Mooseman
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Re: bike idles fine but dies with throttle input??????

Postby Mooseman » Wed Sep 07, 2011 7:59 pm

Be sure and check those vacuum hoses. Easy to miss a conection or two when putting the carbs back in. Will make it run funky if one is unhooked. virgilmobile, is right on the money but check those conections under the false tank and near the gas cap.
Enjoy the ride. They are all good, just some better than others.
Mooseman

b67
Posts: 4
Joined: Sat Sep 03, 2011 9:35 pm
Location: San Francisco, California
Motorcycle: 1986 GL1200 Interstate

Re: bike idles fine but dies with throttle input??????

Postby b67 » Sat Sep 10, 2011 8:01 pm

we worked on the carbs because it would not idle without the choke on and would not rev up, but after some seafoam it would at least rev up. i'll double check the vacuum hose on the left carb, pretty sure i got that one though. i was concerned about the slides. i'll check those too.

thanks gents!

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starfleetengineer
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Location: Elkhart, Indiana
Motorcycle: 1979 Yamaha 650 Special
1978 CB750
1980 Yamaha 650 Special
1983 Honda V65 Magna 1100c
1984 GL1200I Interstate

Re: bike idles fine but dies with throttle input??????

Postby starfleetengineer » Sat Sep 10, 2011 11:29 pm

Also be sure that the o-rings for the manifolds are seated and not leaking and that you didn't crack any of the manifolds when you tightened them down. I broke one when I tightened them down. doesn't take much to crack it. Also be sure you have good o-rings on your air pipes.
How many times do I have to tell ya,,, The right tool for the right job!

b67
Posts: 4
Joined: Sat Sep 03, 2011 9:35 pm
Location: San Francisco, California
Motorcycle: 1986 GL1200 Interstate

Re: bike idles fine but dies with throttle input??????

Postby b67 » Mon Oct 10, 2011 10:21 pm

well, here's an update....

checked all the vac lines and all were good. we got the bike running. apparently there was still a bunch of sea foam in the lines after the first attempt at cleaning it out. that caused a lot of problems for a while because the concentration was so thick. anyway got that cleared out and sync'd the carbs. that made a huuuuge diffrence. the number 1 (left front anyway) carb was backfiring with throttle input regularly and was the main culprit. it runs like a champ when warmed up. its still a little cold blooded and smokes a little on a cold start. prolly time for a valve checkup but that wll have to wait a bit.

anyway thanks for all the help fellas! it was a big help.

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starfleetengineer
Posts: 329
Joined: Fri Jul 23, 2010 7:02 pm
Location: Elkhart, Indiana
Motorcycle: 1979 Yamaha 650 Special
1978 CB750
1980 Yamaha 650 Special
1983 Honda V65 Magna 1100c
1984 GL1200I Interstate

Re: bike idles fine but dies with throttle input??????

Postby starfleetengineer » Mon Oct 10, 2011 11:22 pm

Glad you found it :D I have noticed that the colder it is in the morning the more mine smokes till it starts to warm up. don't know if its normal or not. There is no color to the smoke, looks just like a car warming up in the cold air.
How many times do I have to tell ya,,, The right tool for the right job!

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Mooseman
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1985 GL1200A (SOLD) 85K
1986 BMW K75c 25K

Re: bike idles fine but dies with throttle input??????

Postby Mooseman » Wed Oct 12, 2011 12:15 pm

Yes both of my Wings 85 and 86 have been cold blooded. Pop, snort and cough till warmed up, especially if I try to cut the choke back to quickly. Yes I get the condensation smoke out of the tailpipe on cold morings till warm. All normal. I have found that when cold after shifting into 4th gear I can take the choke off and let it warm up as I move on down the road without ill effects.
Enjoy the ride. They are all good, just some better than others.
Mooseman

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maestro319
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Location: West Chicago, IL
Motorcycle: 1986 Honda Goldwing 1200 Aspencade

Re: bike idles fine but dies with throttle input??????

Postby maestro319 » Wed Oct 12, 2011 2:56 pm

Thank goodness your rides do the same thing mine does in the morning. I thought maybe something needed to be cleaned or adjusted on my '86 Aspencade. It sure is a good feeling to know all that popping, snorting, and backfiring is somewhat "normal" for these older wings. (My wife thinks it's "normal" for me too. :D )




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