Alternative pickups for Kz mechanical-advance ignitions.

In this thread, we were discussing what alternative pickups could be used for our bikes.
www.kzrider.com/forum/4-electrical/61335...d-up?start=48#828653

My favorite option, purely based on price and size is the Chrysler/Mopar pickup form around 1975. It was used on millions of cars and was still being manufactured by aftermarket suppliers last I checked in the early 2000's. I've seen new ones as cheap as $8.

I also happened to have a smaller, one from a Datsun from the same era. It's very similar, but smaller, which is nice. But it generally costs 5 to 10 times more than the Mopar pickup.

First I made a test rig using a Rotozip and a router speed controller from Harbor Freight. Note on the speed-controller: You have to open it up and there is a small hole in the circuit board that lets you access the internal speed calibration potentiometer. You have to adjust it so you can get all the way down to zero, otherwise the range will be very limited.





Here's the Datsun pickup, but I haven't done anything with it yet.

Here's the Mopar pickup.
The first one is new and one I bought at a parts store in the early 2000's I think. It's a Wells aftermarket unit.
The older one is one I used on my 71 Dodge Dart 318 which originally came with points. I got this at an aftermarket tune-up shop in the 1990's.

On the older one, the pickup coil can just slide off the frame. That's very convenient.

Here I was testing the old Mopar pickup by itself. The signal is basically the same as the standard Kz signal but maybe a tad weaker. It's hard to say because the magnetism would be stronger once the pickup is mounted to a steel timing plate. Also, the gap between the pickup and rotor play a huge role in signal amplitude. I had it about 1.2 to 1.5 mm away, which is farther than what I would see normally. With the pickup being mounted the way it is, I was worried it may flex more than what the Kz pickup would, so tighter gap could be problematic.

Here is a Kz inline-four pickup plate. One pickup is removed completely. On the far side you can see the metal skeleton from the other pickup. That skeleton is what transfers magnetism from the base plate to the rotor. The tip is the pole-piece you see on a complete pickup.



What I found was that you can simply place the Mopar pickup coil on the skeleton of the Kz pickup and it works just like a Kz pickup. But it has to be this older type of Mopar pickup in order to physically fit properly.
Note on polarity of the Mopar pickup:
The black wire is what I consider positive. It would go with the black wire or yellow wire on Kz pickups.
The red wire is what I consider negative. It would go with the blue wire or red wire on Kz pickups.




Then I mounted it on a the test rig with a good Kz pickup in the opposite position.

The results are very promising. The signals created are so similar that I can't tell them apart.

I was running low on time so I just made some fast screen shots.
Sorry the images are blurry. The scope screen must have screwed with the camera's focus circuit.

First, here are the two signals one above the other. (I can't remember which is which, but they look pretty much the same to me.)


Next here they are overlayed on each other.


Here's a closer view.

YOU ROCK LOU!!!!
Thanks for all of the wisdom!

That mopar is exactly the one I came across on eBay over the weekend and have been waiting for a reply back from the seller on info so I could try and find some numbers. Nevermind that though. They have it listed for like $15 which isn’t bad at all considering. I think I’m just gonna hit the buy it now button then mount it up on the live test subject once I get it. Also, I finally have the Caltric one for the Polaris in my hand.
Here’s what it ohm’s to..

Later today, I’ll report back with the results from the other tasks you asked from earlier.

Personal question if you don’t mind me asking? Were/are you an electrical engineer. That’s a mighty useful super power you have acquired sir.

Man, it seems like all the old pickups from the 70's and 80's are in the 300 to 700 ohm range and the newer ones are all lower. The only difference I can think of is they are using larger rotors, or maybe they are using the impedance of the pickup as part of the design to control timing advance. The old ones are all mechanical-advance.

Sorry for the late results. Literally just did them. The 40ohm pu that’s mounted does make my spark plug tester light, but very faintly. Can be seen even with overhead lights on. Did the 130ohm and the bulb is significantly brighter? So just for shits and giggles, gonna see if I can ziptie it on and see what happens? Also, the pole on the 2nd pu has about the same more or less magnetic attraction to an 8mm wrench as the stock one. The first test pu has none as far as I can feel when setting my wrench on its pole.

Old Toyota supras, MR2’s and the like are abundance in my area as well as Nissan/Datsuns. Wish I could find a decent bodied 77 240? I miss mine now..oh the things I’d do to it:whistle:

And just in case. Here’s the ID of the rotor/pulser area.

I found this from RMstator and then did a quick search on eBay for availability.

In the description, says this is a 500ohm coil? Price isn’t too bad either.



I pressed the buy it now button:whistle:

That looks good, but the real question is does it include a magnet inside.

Yeah, I miss my old Datsuns. I had two 260's. They were pretty much rusted to nothing by the early 1990's.

So the 130ohm pu does work and just like you guys mentioned, it may be hard to start. But I gas supply had a good percentage for that since I had them off for the time being. But yeah, I do intact get spark and can get it to fire with the kick start. I’ve got a stock yuasa I’m charging right now to aid me further since I did the hard part of kicking..lol. I’ve got maybe 3-4 hours left till the battery is charged. If it actually starts and runs..well whatever happens, I’ll report back with the results. Oh and that 500ohm pu I found, the seller cancelled the order cause they didn’t have it in stock..booo