Leaving the ignition on with the engine not running will heat one coil depending on which set of points is closed, leave it that way very long and the coil will burn out.
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I am Carbon
shade tree mechanic
Just to mention the stock coils are just arent that good when they were new. I would replace them anyway. you also said your plugs were wet. even with good spark your pilot could be way to rich for some reason and it will not start. Have you tryed a shot of starting fluid to see if she fires.
On your coils the one on the right has it's plug wire going to the right side plug. That makes that coil the right one. Same on the left.
On your points the upper set is for the right side. Whatever color of wire hooked to the upper points hooks to the right side coil.
To do a few electrical tests you need a multimeter, a digital one is easy to read.
To test which wire hooks to which set of points, set the meter to the 200 ohm scale. touch one lead to the upper set of points, touch the other lead to where the points wires plug into the coil. If you get a very low ohm reading that is the upper points set wire. If the reading stays at infinity then the right points wire is the other wire. The one with continuity is the one your looking for.
To actually test the coils you need to test for the primary side ohms and the secondary side ohms.
Lets start with the primary side ohms. With your meter set on the 200 ohm scale touch the probes together. This reading you get is the resistance of just the leads. remember this reading, lets just say it is .4 ohms.
Now unhook the two small wires from the coil, touch one probe to each small wire. Lets say you get a 4.3 ohm reading. Now subtract the first reading from the second reading, as in 4.3 - .4 = 3.9. Your stock coils should have a 3.9 ohm primary. anything from about 3.5 to 4.5 is ok.
On the secondary side unscrew the plug wire out of the coil, set your meter to the 20,000 or 20k scale. Touch one probe to the little screw inside the coil where the plug wire goes, the other to one of the mounting lugs. You should get about an 8000 reading. Anywhere from about 7000 to 9000 is ok.
If both coils test out ok then they shoulkd be fine for now. If bad you need new ones.
There are many ways opyions on coils. The stock coils are about 8000 volts output at 4000 rpms. Not a very strong coil. It takes about 6 or 7000 volts just to fire a plug.
Many coils out there put out 20,000 or better volts. These will fire the plugs much better. As long as the primary ohms is very close to the 3.9 ohms of the stock ones. most aftermarket coils for points run 4.5 to 5 ohms. Any of these are ok.
You can hook up a dual out put coil to your bike by hooking both sets of points to the coil. A dual output coil is a coil that has one set of primary wires and two sparkplug wires on the secondary. So you hook both points to the primary side.
This will fire both cylinders at the same time. Just as the later electronic ignition.
Leo
On your points the upper set is for the right side. Whatever color of wire hooked to the upper points hooks to the right side coil.
To do a few electrical tests you need a multimeter, a digital one is easy to read.
To test which wire hooks to which set of points, set the meter to the 200 ohm scale. touch one lead to the upper set of points, touch the other lead to where the points wires plug into the coil. If you get a very low ohm reading that is the upper points set wire. If the reading stays at infinity then the right points wire is the other wire. The one with continuity is the one your looking for.
To actually test the coils you need to test for the primary side ohms and the secondary side ohms.
Lets start with the primary side ohms. With your meter set on the 200 ohm scale touch the probes together. This reading you get is the resistance of just the leads. remember this reading, lets just say it is .4 ohms.
Now unhook the two small wires from the coil, touch one probe to each small wire. Lets say you get a 4.3 ohm reading. Now subtract the first reading from the second reading, as in 4.3 - .4 = 3.9. Your stock coils should have a 3.9 ohm primary. anything from about 3.5 to 4.5 is ok.
On the secondary side unscrew the plug wire out of the coil, set your meter to the 20,000 or 20k scale. Touch one probe to the little screw inside the coil where the plug wire goes, the other to one of the mounting lugs. You should get about an 8000 reading. Anywhere from about 7000 to 9000 is ok.
If both coils test out ok then they shoulkd be fine for now. If bad you need new ones.
There are many ways opyions on coils. The stock coils are about 8000 volts output at 4000 rpms. Not a very strong coil. It takes about 6 or 7000 volts just to fire a plug.
Many coils out there put out 20,000 or better volts. These will fire the plugs much better. As long as the primary ohms is very close to the 3.9 ohms of the stock ones. most aftermarket coils for points run 4.5 to 5 ohms. Any of these are ok.
You can hook up a dual out put coil to your bike by hooking both sets of points to the coil. A dual output coil is a coil that has one set of primary wires and two sparkplug wires on the secondary. So you hook both points to the primary side.
This will fire both cylinders at the same time. Just as the later electronic ignition.
Leo
jdm9123
78 xs650SE
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Thank you I will try all of those tests now. I also just remember that the bike came from Minnesota and is now in Florida. I would have to assume it needs re-jetted now because of the elevation change.
probably no jetting was done, most of Minnesota is around 1000' msl not that high
