Front 2 cylinders sooting up


Information and questions on GL1000 Goldwings (1975-1979)
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nicklaw
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Motorcycle: 1975 GL 1000 Gold Wing

Front 2 cylinders sooting up

Postby nicklaw » Thu Jan 13, 2011 5:00 am



Hi, have a 1975 GL 1000, just did 5000kms roadtrip but front 2 cylinders spark plugs sooted up, (dry black soot) every 60 miles or so. Rear cylinders plugs good tan colour. Has anyone else had this experience? Can the chokes on the front carbs jam on? Where can I find a clear carb diagram/ Many thanks...



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dingdong
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Re: Front 2 cylinders sooting up

Postby dingdong » Thu Jan 13, 2011 9:15 am

Symptoms of those two cylinders running rich. Too much fuel or not hot enough spark. Could be floats or one bad coil. I would look for a coil, plug or plug wire problem first.
Tom

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virgilmobile
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Re: Front 2 cylinders sooting up

Postby virgilmobile » Thu Jan 13, 2011 10:52 am

The front and rear chokes are solid linked together,that's not the problem.If I had to guess,Verify enough spark.If ok then. suspect the slides are stuck open dumping too much fuel to the front cyl.Second..front carbs are open more than the rear(check with vacuum test).Third...high fuel level,the carbs need to have the same amount of fuel in each bowl.Lastly..compression is low in the front cyls(compression test).In theory,The carbs dump fuel at the same rate to all cyls during running,all cyls burn all the fuel and it's happy.2 cyls sooting up means the cyls can't burn all the fuel provided.

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WingAdmin
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Re: Front 2 cylinders sooting up

Postby WingAdmin » Thu Jan 13, 2011 3:27 pm

I'm looking at it from the aspect of what do the two front cylinders share?

In terms of slide adjustment (synchronizing), the right two (cylinders 1 and 3) and the left two (cylinders 2 and 4) are synchronized to each other, then the left bank (2 and 4) are synchronized to the right bank (1 and 3). The likelihood that the front two cylinders (1 and 2) happen to be out of adjustment, while not impossible, is not that likely.

Looking at the plug wiring, however, the front cylinders do share a component: a coil.

4 Cylinder Wing Coil Wiring
4 Cylinder Wing Coil Wiring


So if the coil running the front two cylinders is weak or failing, it could cause a weak spark in the front two cylinders, which can cause sooting.

Try swapping the coils. If the front two cylinders start running fine and the rear two start to perform badly, you know you've got your culprit.

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virgilmobile
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Re: Front 2 cylinders sooting up

Postby virgilmobile » Thu Jan 13, 2011 4:26 pm

Sense we don't know the past history(first 5k ride,previous adjustments,etc.)we can only generalize.>Poor spark,too much fuel,or low compression.Like I said:from most likely to least likely.Virgil

imfree
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Re: Front 2 cylinders sooting up

Postby imfree » Fri Jan 14, 2011 6:49 am

No one said any thing about the pilot screws,Could they be out of adjustment, but I would check the coil frist.

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virgilmobile
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Joined: Sun Sep 19, 2010 5:39 pm
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78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Front 2 cylinders sooting up

Postby virgilmobile » Fri Jan 14, 2011 8:06 am

Is the bike still running with points?One set per coil.One can be out of time,bad cap,etc.Virgil




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