Cylinders 1 and 4 no spark

[jjerome]

My 1980 GS850GLT will only fire cylinders 2 and 3. I get no spark on 1 and 4. Suspected a bad coil. I swapped the input lead from the suspected coil and connected it to the good coil. That caused 2 and 3 not to fire. Does anyone know if this could be a points related issue? Any help with diagnosing would be appreciated. Thanks Jim

[lrburke]

gs850

I would say you have a points problem. If you did the old switchem technique then the points are what causing it in my opinion! If it was just one cylinder not firing then I would wonder but not in this case. Do you know how to set the points and all that good stuff? Larry

[jjerome]

Thanks for the fast response. I have not had to deal with points on this year/model. I have a few manuals. Are the points easily replaceable as a single unit?

[rustybronco]

My 1980 GS850GLT will only fire cylinders 2 and 3. I get no spark on 1 and 4. Suspected a bad coil.

You don't have points.

check the resistance between the 1 & 4 plug caps (the things that go on the spark plugs) what is that measurement?

see...

http://www.thegsresources.com/_forum/showpost.php?p=1048906&postcount=2

[jjerome]

Sorry to sound ignorant but how do I check resistence? I have a friend that is more knowledgeable than me and he checked the voltage to the coil. It was extremely low compared to the "good" side coil.

[rustybronco]

Sorry to sound ignorant...

No such thing. only un-asked questions. (or have not done that yet)

you would use the same meter, but set on the resistance scale.

if you don't have a Volt Ohm Meter, I would suggest that you buy one instead of borrowing your friends, or having to wait for them to stop on by. you can find a good workable unit for less than $20 USD at harbor freight, radio shack, big box hardware stores, ect.

***come, sit a spell, learn and enjoy the company...***

[jjerome]

I have a meter. Where do I make contact with it and does bike need to be running or just Ignition switch on?

[850 Combat]

From what you have written, I would suspect a bad coil, If I undertand your meaning correctly.

an '80 should not have points. Possibly you have a '79, as those have points. I got a '79 850G free because the PO thought the motor was bad. It needed a condenser. My nephew has been riding it for years.

[rustybronco]

key off... knob on meter set to resistance 200K scale...
one lead goes into the #1 plug cap the other into the #4 plug cap.

[jjerome]

Thanks for the clear and concise instructions. I will measure it in a few and post my results.

[jjerome]

Could be I measured wrong but I get no reading on the meter. I used the same scale on the handlebars and got a measurement there.

[rustybronco]

Just what i had suspected...

did you read the link I had posted? http://www.thegsresources.com/_forum...06&postcount=2
it will tell you what to do next...

[jjerome]

I will do the next steps. However when I did the same resistence test on plug caps from 2 and 3, I still did not get a reading.

[rustybronco]

start with removing the plug caps and measuring the total resistance through the
[plug wire]-[coil secondary winding]-[plug wire] without the plug caps installed.

are you sure you had good contact with the connection(s) inside the plug caps?

[jjerome]

Pretty sure. I wiggled it around to make sure I felt some of the threads inside