replacing pick up coils

81 xj550 maxim
one of my pick up coils failed open, I have a plate on the way. I plan on replacing it as an assembly.
can I salvage the remaining good coil off of the plate and use it in the future to replace a single coil on the plate?

a little back ground.
my 2 and 3 cap resistors failed in the plug caps one went open the other went to 47k ohms ,
along with one of the pick up coils.
how it started
went for a ride came home bike stalled ,thought I had a fuel problem big bubble in fuel line. fixed it
next day stalled after 6 miles for good.
checked for spark had none on 2&3. started my check of the ignition system using flow chart from FSM, stopped when i found the resistor cap problem.
should have completed the flow chart because it would have led to me finding the bad pick up coil on same day
not 5 days later when the resistors arrived.

 

Yes, you can save the working pickup for a rainy day.

The only complications I can think of would be things like getting the wires up through the harness wrap. Or that the two pickups (I think) have different length wires. If you're saving a short one, it might not be long enough to use in the long position without a splice. Or that the wires are different colors.

In other words... Small surmountable problems.

 

they both have a common connection done with a little band to connect both black wires then runs to the tci plug
then the two colored wires run to the tci plug. so i guess the worst case is i may confuse the next owner with 2 pick ups of the same color and I will become a f@@@ PO

 

Right. Splices, non-original harness wrap, wrong wire colors. That kind of stuff.

In other words... The pickups are mechanically and electrically the same with the exception of the wires coming out of them. I'd keep it too. In fact, I'd keep both of them and dissect the failed one to see if I could figure out exactly where the open circuit occurred. For all you know, both your old pickups themselves are fine and the open circuit is where the two grounds are spliced together inside the harness wrap.

Haha! I'm not saying it's likely, but it is possible.

I think back to all the vehicles that I've sold in my past. I wonder if I've ever been thought of as the f@@@ PO. I believe it would be unrealistic to think not...

 

something i noticed on the last few rides before the failure , when I started the bike with enrichment circuit after about 90 seconds the rpm/pitch (sound) of the motor went up a little, now with replacment pickups it does not happen. was that a tell tale sign of pick up failure?

 

Tough to tell. Those kinds of (coil) failures usually go intermittent with temperature before they fail hard, but I think that if the pickup was in that intermittent stage, you would have been misfiring on two cylinders and would have noticed something more extraordinary than a slight RPM increase.

In other words, it's conceivable that your pickup wasn't working when you first started the bike and then after 90 seconds it got warm enough to (temporarily) start working. But I think you would have noticed the fact that you were missing badly on 2 and 3 for the first 90 seconds until the pickup started working?

It's also conceivable that you're getting a better spark because you changed caps. Or maybe it was just messing around plugging and unplugging a bunch of connectors.

So, did you start stripping down your old pickup set yet to find the break?

 

I have the casing of of the wire harness did not find a break in the wires, it looks good visually at all the stress points in the layout path where your toe kicks it at the shifter/sprocket cover, where it crosses the swingarm.
the factory splice for the common black was solid,but had a few strands out side the connector. the pickups look a little bent compared to the new set whick came off of a bike with 9000 miles . looked brand new except for the connector housing for the tci was chiped up ( getting a new one and connectors) .
i am going to use a pin to probe into the wire and do a continuity test from the connector to the pickup to check on the orange wire.
then see if i can open the body up today

 

Well I'm certainly no expert, but I have dissected a couple similar devices (relays, fuel injectors, etc.) and I've found that most of the failures occur at a transition. usually the transition where the magnet wire (the internal windings) connects to whatever metal passes through the case and into the body of the device.

So I'd very carefully carve away the case material where the wires lead into the case, and I'd look for a failure right where that external wire is connected (crimped or soldered) to the tiny gauge magnet wire that is wound around the magnet into a coil.

Of course, I could be completely wrong as well! I live for that!

 

There comes a point where time spent on repair/diagnosis becomes excessive when there are working replacements available.

 

are there after market pick ups available?
I know len did not have mine listed.
i got an ebay setup they look new. claimed 9000 miles on bike

 

Used ones are fairly easy to find. I'm not saying that you can't fix yours, but how much time do you want to spend? It is really unusual for them to fail, even from a broken wire so it won't be that much of a gamble getting a used set.

 

You're saying that if he dissects his failed pickup coil and finds exactly where the break occurred, you won't open this thread ever again to look at the detail because you think it was a waste of time to look in the first place?

Myself? Available replacement or not, I think it's neat to just to know. That information may or may not ever become useful in the future. But if it does, I'll know.

 

I'm saying nothing of the sort and I would figure that you've read enough of my posts by now to know that.

Priority one is having a bike on the road.
Priority two is satisfying curiosity regarding a faulty part and trying to salvage it.

 

I will be opening it up but just to satisfy my curiosity, i am wondering if it caused the resistors in plugs 2+3 to fail or the failed resistors caused the pick up to fail.
47K ohms for one full open on other.
I did pick up another set really clean 9k miles on them. what a differnce in performance over prefail.