Oozing coil?!?

[AirsoftNY]

1980 Special, PMA swap and Pamco ignition installed.

First time starting the bike with the new PMA and Pamco installed. I'm getting no spark, and I'm turning the starter over sporadically over the course of 5 minutes while I poke around with my multimeter to find out why sparks are eluding me.

I start to smell a bit of a burning electrical smell, and sort of a sizzling noise from the coil. The coil is hot (not burning hot) and this black goo is oozing out of one end.

Has this ever happened to anyone? I'm guessing the coil is shot?

thanks

Aaron

 

[xjwmx]

Meltdown. Too late to run. Well, probably your primary side of the coil is lit up all the time. Need to find out how come and fix it. Nothing else could get it that hot. Possibly a fried Pamco output transistor behind it.

 

[AirsoftNY]

XJ,

Will a new coil solve this, or is something else causing the coil to meltdown?


thanks

 

[xjwmx]

Try firing it up one more time and see if there's always ground on one side of the primary and +12 or so on the other. If so, it's got to be a wiring mistake or the Pamco transistor is blown (or both). Would be handy to have an oscilloscope there to see better. Something about leaving the ignition on with the engine off for a length of time will damage the coil or Pamco transistor; I forget exactly what happens.

 

[XSLeo]

I agree with xjwmx on the wiring. If you have it wired wrong you will have power flowing through the coil all the time, this can overheat the coil, melting the insulation , thus the black ooze. I might unhook the coil and test the primary side to see if it ohms to spec, with no short to ground.
If wired right, when you turn the key on and engine stop switch in the run position, power flows to the coil and Pamco, when you try starting, the Pamco reads signals from the magnets in the ignition rotor. These magnets tell the Pamco when to turn the main power transistor on and off.
When the transistor is on power flows through the coil, when the transistor turns off, power stops.
As power flows in the coil it builds up a strong magnetic feild, when the power stops the magnetic feild collaspses and this collapse creates a very high voltage in the secondary of the coil. This high voltage is what sparks the plug.
If the transistor is faulty and somehow is stuck on, then power will flow in the coil all the time. This seldom happens.
I would check the wiring to be sure it's correct.
Pamcopete will read this soon and tell you more about it.
Leo

 

[pamcopete]

AirSoftNY and XSleo,

The number one cause of your condition is leaving the ignition on with the engine not running. The number two cause is incorrect wiring, specifically connecting the black wire from the PAMCO to one terminal of the coil which then grounds that terminal and the current flows continuously through the coil.

In both cases, the coil is probably fried, literally. The PAMCO could also be fried with case #1.

Check your wiring for case #2. Measure the resistance of the primary of the coil to see if it is fried.

All PAMCO's are dynamically tested prior to shipping so the transistor was fine when it left here. Complete installation instructions are available on www.yamahaxs650.com

If the PAMCO is fried, then you will only have have the PC board replaced.

XSLeo...thanks for the help. Very good description.

 

[AirsoftNY]

Thanks all, very helpful as usual!

Unfortunately I'm away from the bike this week, won't be able to check it until the weekend. Will check in though, soon as I can.

Kicking myself thinking I wired it wrong, my first rewire from scratch and I was trying to be extra careful...

Aaron