Electronic ignition trial - Harley dual fire

[tcanthonyii]

Well I asked about this a couple years ago and curiosity has finally gotten me. I ordered from eBay a cheap 70’s sportster dual fire ignition module. $50.

First thoughts. It won’t work out of the box I’m guessing. The magnets are not in the same place between the two rotors and the Harley is deeper. Also the adjustment is different between the two. See the pictures below. I don’t have time tonight but maybe tomorrow I’ll throw it in the cart. I'll dremel out the points plate for adjustment and use the original rotor. I also have an internally resisted coil to use with it. I’m hoping it works but we’ll see. In theory it should. If it does it’s a fairly inexpensive way for folks with a rotor to get spark without points or an HEI module. Someone then really could fairly easily produce the rotor or make a 3d print file to insert magnets in. Maybe I can model one with my buddy and test as well.

I wanted to test it so on my spare motor but it’s older and the crank is different and appears to only accept a point plate. More to come!

[tcanthonyii]

The answer is yes it works. However the modul died before I could drive it. It does the same thing the factory module does and spark only when letting off the throttle. I’m ordering another one and am going to put a balast resistor in line to see if it helps. My cart put out too much voltage even after swapping several voltage regulators and I’m assuming the module is touchy to that.

I’ll report back once I get another module. Assuming I get it to work full time I’ll have my buddy design a 3d print for the rotor and figure out how to take the magnets out of the Harley router. If that all works out then we all have an inexpensive option.

See pictures below for dremel work for adjustment. It’s terrible looking but did work. Also the plate is slightly too large and needs filed down but I wa expecting that since others have used points plates from sportsters in the past and reported they are just a hair to large.

I’ll let you know in a couple weeks. Have some vacation line up.

[tcanthonyii]

Circling back to this. I ordered 2 more modules. No go on either and burned them up as well. I'm sure if I could find the secret sauce it would work just fine. Probably need the correct coil from harley to make it work right. I got tired of throwing money at the test.

I tried an internally resisted coil, a non resisted coil and a non resisted with a ballast resistor. Same results and non lasted as long as that first one.

Too bad because this seemed super promising.