Coil Troubles (need help!)

[The_heartbreak_kid]

So I was riding my bike on a hot day day today and when I turned the bike off for a few minutes the bike wouldn't start.

Im pretty sure I have narrowed it down to a bad coil. When I turn the ignition switch to on. One of the coils gets very hot (Im assuming this is the good one) and the other one stays cold.

Is this correct? Whats my next move and how should I test this?

 

[Classic]

How hot is the working coil? Does it pass the 5 second test?

I would first suggest turning up the idle and starting the bike... If the spark is bad on one side it will only run on one cylinder. Take ignition leads and signal wires and switch between the two cylinders. If the firing cylinder switches sides than you probably have a bad coil. You could also have old points (what year is your bike?) or a bad plug wire or cap with too much resistance.

If it is a bad coil you could get a replacement for dirt cheap on the forum or from mikes.

 

[malloym]

did you ohm out the primary side???

 

[The_heartbreak_kid]

No its VERY hot...you can barely touch it.

The bike wont start at all though. When I tested both plugs the spark is very weak. Small orange colored spark on each side when I use the push start. Fuses are good and Battery is a brand new xs performance battery from mikes.

It seems weird that I get spark on both sides but one coild is super hot and the other is cold.

 

[The_heartbreak_kid]

did you ohm out the primary side???

I just did...I think its shorted.

First time testing a coil though, so can you explain it to me like Im an idiot to make sure Im doing it right?

 

[Tomterrific]

Points bike right? One point is closed charging the coil, the other point is open so no current to the coil. Turn engine 360° and the opposite coil gets hot. My XS and Triumph always stops on the left coil for some reason. That one is always hot with the key on.

BTW, bad to let bike sit with ignition on. The coil that the points are closed constantly has current heating it up. I boiled all the oil out of my Lucas coil on my Triumph when I forgot to turn off the key. Yes, even the ignition on my Triumph leaks oil. {8^o I filled the coil back up with mineral oil and it's fine, still running years later.

Mikesxs battery? Hmmm, there's been a problem with some mikesxs batteries. Two of them sidelined a friends really sweet XS cafe for 2 years until he finally bought another battery. Jump the bike with another battery or a real battery charger and see if she will start.

Tom Graham

 

[gggGary]

dry the plugs and try to start it again. Vapor lock happens on hot days...... Gas boils in the carbs and floods the engine.

 

[The_heartbreak_kid]

thanks guys....Im going to play around with some of the advice and will update when I get to the bottom of it.

 

[XSLeo]

Your repair manual tells how to test a coil.
Leo

 

[Huck818]

Heartbreak Kid,
Did you ever find out what your issue was because I have exactly the same issue I am fighting.