Ive done some looking around for cheap alternatives to the vape ignition system, and is seems that a Blaster Flywheel would fit on the crank of the dynamo models. once measuring everything out the crank beginning starts at, roughly, 1/2"  and tapers back to 3/4" (12.7mm to 19.05mm). The Blaster flywheel goes from 0.51" to 0.74" (13mm to 19mm). This is the same taper as the stock Dynamo, with the same taper length too. You would need to make a backing plate for the magneto, but I have a cnc plasma cutter to do that for me. This coupled with rexs-speedshop's CDI,  for the 125mx seems like a great budget way to get rid of a battery and replace the old dynamo for a nice upgrade in reliability and potentially power. Want to see if anyone has done this before, and your opinions on it. ( I got the idea after watching Dale Sweger)

I think what you'll find on the dynamo model is the crank stub is slightly shorter than on the magneto models.

May not be an issue...  or Blaster flywheel could rub the stator plate?

Also wiring on the Blaster stator comes out of engine towards the front...  might not be a problem but if you want to use the crank key you'll need to keep the stator coil orientation about the same as it is on the Blaster.

74- on Magneto models have the same 120mm OD and two bolt mounting pattern as the Blaster.  Earlier models 125/175 and all 12 volt electric start models have a 130mm stator diameter.  

The AG models in the Australia region came with a CDI in the later years...  I think it might have the 130mm stator and might bolt right on to the e-start and earlier 175's with the worm gear clutch actuator in the ignition side cover.

Yes I did notice that the wiring came out the back of the magneto/stator. I will design the plate to accommodate for it.

I am unsure of what a crank stub is? If it does rub I can thin the plate out.

I looked and couldnt find any AG model magneto and a flywheel in good condition for a decent price. Right now I can get everything I need for $140. Will keep my eye out though.

Once I get everything done I'll make a post to the customs page as the bike is slowly turning into a mix of many things. Hoping to get it on a dyno sometime to see if my cheap modifications have increased the power and whatnot.

 

Crank stub is the part of the crank sticking out of the crankcase with the taper on the end.

I'm pretty sure it's a little shorter on the dynamo model... which means flywheel will be closer to engine case/stator.

The crank stub is 34.925mm from the crank seal keeper plate to the end of the stub. Taper length on the blaster flywheel is 33mm.

I am unsure of how the pickup works. on the blaster the pickup sits on the inside with no mark to indicate when to fire.

Alright this is where I'm at on the wiring diagram. I'm not sure where im going to put the ground, but other than that its solid.

Wiring Diagram


 

Why aren't you using a Blaster CDI box? Another model "might" work but Blaster CDI boxes are readily available... and not expensive...

Might have to try that first . Looks like I can buy one for $50. Any good aftermarket brands?

UPDATE:

Well after many attempts and variations I was able to make a plate out of sheet metal and mounted the stator with threaded rivets. I grinded down quite a bit of thickness off of the back of the stator to make due, but in the end the Flywheel grinds into the stator due to the flywheel being different lengths than the crankshaft. Using a blaster cdi box I made my own wiring loom and used a aftermarket ignition coil off of a three wheeler I had laying around. It does run fine, but it needs further adjustment and I stopped working on it due to other race bikes im building in the mean time (xr600r with cr500 white brothers suspension and many more mods). I will be taking all my modifications off of my Dt125 because I plan on restoring it here at the start of summer.

If on the side chance anybody wants the electrical system I built to finish it for the kicks and giggles I would be happy to get it off of my bike and shelf for something like $50 and free shipping.

Thanks for the interesting & technical update. Always good to read.