1980 XS1100G poor running

[kingsdrmr]

Help! I am the proud owner of a 1980 XS1100G which I totally love riding except the bike exhibits occasional poor running: seems like it is missing on one cylinder. Used to happen when riding in rain only but now it can happen any time. Went for ride last night and the bike ran perfect. Just came back from a ride with my daughter and the bike ran terrible. No change except just a different day. I suspect a bad coil. The carbs were cleaned and synch'd a couple of years ago. New carb intake boots installed last year. When the bike runs good it runs great. When it's not..runs terrible. Any suggestions? Thanks.

[DGXSER]

Definitely sounds electrical to me. I'd apray little water at it while idling and see where it starts sputtering. Especially look at the high tension wires to the plugs.

[fredintoon]

Help! - - - the bike exhibits occasional poor running: - - - seems like it is missing on one cylinder. - - - I suspect a bad coil.

Hi Drummer and welcome,
not saying you don't have a dodgy coil but the prime suspect for intermittent misfiring is the wiring to the ignition pickup coils.
Go to Forums/Repairs/Battery & electrical/Pickup coil wire repair to see the quick fix.

[CatatonicBug]

I had a crack in one of my coils, and it would die in the rain, or immediately after washing. I filled the crack with JB Weld, and now rain doesn't affect it.

[XSokieSPECIAL]

Make sure you don't have a contact problem withe the spark plug caps.

They screw/unscrew onto the wires. Unscrew them and trim the wires back about 1/4" and screw the caps back on.

See if that helps.

Misfire in the rain is sometimes due to bad sparkplug caps also. I replaced mine and it made a HUGE difference.

I'll see if I can find the link to order new ones. Unless someone else here knows.

[bikerphil]

Link for inner cyl. caps...

http://www.parkeryamaha.com/ngksparkplugcapxb05f.aspx

Link for outer cyl. caps...

http://www.parkeryamaha.com/ngksparkplugcaplb05f.aspx