Coil Test


Information and questions on GL1100 Goldwings (1980-1983)
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penntoy123
Posts: 48
Joined: Sun Jun 12, 2011 5:01 pm
Location: jacksonville, nc
Motorcycle: 1982 GL1100A Aspencade

Coil Test

Postby penntoy123 » Sun May 20, 2012 11:49 am



I am still having mpg problems, I posted about my compression (haven't had time to finish testing that yet, until now). I did an ohm check of my coils. I pulled the plugs and measured from the cap to cap of each coil and they measured approx. 27k ohms. The shop manual calls for 16.7k for an 1982 and 22k=/- 5k for 1980-81. I have a 1982 gl1100A, So far it looks like I may have the wrong coils installed. Would this cause my poor milage and carbon build up on the spark plugs? Or do I need to pull the coils and measue the coils with out plug wires? I have measured everything prior and everything else is within tolerence. 23 mpg is just not right!



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patbrandon1
Posts: 442
Joined: Mon Mar 26, 2012 1:39 am
Location: Bay City, Michigan
Motorcycle: 1982 GL1100 I
1981 Honda CM400C

Re: Coil Test

Postby patbrandon1 » Sun May 20, 2012 5:14 pm

penntoy123 wrote:I am still having mpg problems, I posted about my compression (haven't had time to finish testing that yet, until now). I did an ohm check of my coils. I pulled the plugs and measured from the cap to cap of each coil and they measured approx. 27k ohms. The shop manual calls for 16.7k for an 1982 and 22k=/- 5k for 1980-81. I have a 1982 gl1100A, So far it looks like I may have the wrong coils installed. Would this cause my poor milage and carbon build up on the spark plugs? Or do I need to pull the coils and measue the coils with out plug wires? I have measured everything prior and everything else is within tolerence. 23 mpg is just not right!


Carbon buildup on the plugs is a sign that it isn't firing as needed. Are all of your plugs carboned? If so I would shoot at the regulator rectifier because it is unlikely they are the wrong coils. It is possible though. And measuring the ohms is best done without the wires. There is some resistance in those, and will show up on the reading. But the wrong coils would cause your problem with low mileage. My GL1100 gets around 38 mpg. Go on Ebay and search for coils for GL1100's and you will see what they look like. How does the bike run? Do you have any power at all? Remember, plugs for cylinders 1 + 2 are the right side coil, and 3+4 are the left side coil.

User avatar
penntoy123
Posts: 48
Joined: Sun Jun 12, 2011 5:01 pm
Location: jacksonville, nc
Motorcycle: 1982 GL1100A Aspencade

Re: Coil Test

Postby penntoy123 » Sun May 20, 2012 6:09 pm

I'll give the rectifier a try. I removed the plugs to check the sparks and all 4 are weak and heavy carbon deposits.
It runs ok, but it seems about 50 or so it acts like I am topping out. I would think I should get 70+ out it.

User avatar
patbrandon1
Posts: 442
Joined: Mon Mar 26, 2012 1:39 am
Location: Bay City, Michigan
Motorcycle: 1982 GL1100 I
1981 Honda CM400C

Re: Coil Test

Postby patbrandon1 » Sun May 20, 2012 8:03 pm

penntoy123 wrote:I'll give the rectifier a try. I removed the plugs to check the sparks and all 4 are weak and heavy carbon deposits.
It runs ok, but it seems about 50 or so it acts like I am topping out. I would think I should get 70+ out it.


You should be able to take that bike to 85+ EASY.Run some seafoam in the gas, adjust the valves, and sync the carbs, and it should have more power, and speed. Two years or so ago, one of my coils went out while I was out for a ride. I could not get past 50, and it took a long time to get there. In my case the front two spark plugs were all carbon, so I knew it was the right coil. In your case, I still think it is a spark problem. Could be the rectifier, could be the coils. When you test for spark on these 1100's, it is HIGHLY recommended that you keep the plugs in, and use a spare plug, and do not let it not touch ground. Because it can ruin your ignition system. ALWAYS keep spark going to all plugs.

Now if I were having your problem, I would make sure the coils are the right ones. Make sure the coils are attached to the plugs correctly. When you said the spark was weak, unless you do it in the dark, it may look a little weak, and if they were the plugs with carbon on them it would make it harder to see a good spark as well. It still has me a little baffled though because you have all 4 plugs fouled. I hope someone with a little more experience will see this and offer you some more insight. But I would check everything twice, to make sure what is naughty, and what is nice. Keep us posted.

User avatar
penntoy123
Posts: 48
Joined: Sun Jun 12, 2011 5:01 pm
Location: jacksonville, nc
Motorcycle: 1982 GL1100A Aspencade

Re: Coil Test

Postby penntoy123 » Mon May 21, 2012 5:51 pm

I was able to get out to garage and finish the testing, the rectifier tested good. I then cleaned re-gapped the plugs and check for spark, they looked better after the cleaning. Now I am down to last options, valves and rings. I already had the carbs cleaned and sync'd. Oh well the search continues.

User avatar
patbrandon1
Posts: 442
Joined: Mon Mar 26, 2012 1:39 am
Location: Bay City, Michigan
Motorcycle: 1982 GL1100 I
1981 Honda CM400C

Re: Coil Test

Postby patbrandon1 » Mon May 21, 2012 10:43 pm

penntoy123 wrote:I was able to get out to garage and finish the testing, the rectifier tested good. I then cleaned re-gapped the plugs and check for spark, they looked better after the cleaning. Now I am down to last options, valves and rings. I already had the carbs cleaned and sync'd. Oh well the search continues.


Not knowing if you belong to any other Goldwing sites, I am just going to send you links to two of them other than this one, that may be able to help. They are similar in so much as having forums where you can ask questions. Just a little different setup is all. Here they are...http://classicgoldwings.com/forum/ and... http://www.ngwclub.com/forum/

Maybe someone there has some better info for you. I also was thinking that checking the voltage during running would tell you if you are getting enough power to the coils. You should be getting between 13.5 and 14.5 volts at 1000 rpms. Just a thought.




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