coil

[yellowjacket]

Tried to start my 1980 gs850 for the first time last night. I had gas, compression, and spark and it would not start. Checked the other coil for spark and there was nothing. I cut the spark plug wire back a bit and reapplied the boot, checked and cleaned the connections, still no spark. Before i replace the coils is there something else I should check before i purchase new coils. First time for me with a GS.

[Burque73]

You can swap them and see if it's the coil or not. The left goes to cyl 1 and 4, the right goes to 2 and 3. Unplug the coils, swap one for the other and try again. If you get spark, it's the coil that's bad. If not keep tracing back till you find the problem. I hate electric problems but I'd first download a manual from Cliff's site, if you don't have one, and read through the section on ignition.

Do you have a multimeter?


May help if I give a link or two huh?
Manual for the 850

http://zeus.mtsac.edu/~cliff/storage/gs/GS850_Manual_HiRes.pdf

found here

http://members.dslextreme.com/users/bikecliff/

Coil repair by Cliff. This may very well be your issue.

http://members.dslextreme.com/users/storagecliff1/images/simple_coil_repair.pdf

[yellowjacket]

Thanks for the reply. From left to right #1,2,3,4 spark plugs. I have no spark in #1 but spark in #4. Those two are from the same coil? I should probably check #2,3.

[Burque73]

I'm no expert on these but trying to help, just fyi. I spent some time a couple of weeks ago replacing my wires in the stock coil because the original wires and boots were cracked. I'm thinking the coil still works if you've got spark on 4 but not 1 as yes, they are from the same coil. What does the plug wire connection to the coil look like? Maybe #1 wire loosened up and came out of the pocket in the coil? Or your cap is bad?

DO YOU HAVE A MULTIMETER? You can check resistance in the cap, wire, from one end to the other like cap on # 1 to cap on # 4. That should be around 30k.

[yellowjacket]

Thanks. I will check it out tonight and get back to you.

[yellowjacket]

Thanks for the advice on checking the boot on #1. It was the boot. Changed it out, put gas to it and it fired right up. Made me wonder how long it had been since it ran. Manifolds are toast. you can hear it draw air and when i spray it with carb cleaner it revs way up. I am making this bike for my son. Now that it runs I can really get started.

[Burque73]

You bet. Thanks for the follow up post.

[abaton6]

Do you have a link to Cliff site. I'm new here with an 81 GS 650 with coil problems. Thanx!

[Burque73]

Do you have a link to Cliff site. I'm new here with an 81 GS 650 with coil problems. Thanx!

Try this.

http://members.dslextreme.com/users/bikecliff/

[abaton6]

Thanks!........................................... ....