Vespa PX125 conversion

JimVonBaden

JimVonBaden

Member
Not your typical ebike conversion here, but I thought it might interest some. Starting with a 1981 Vespa PX125, see photo and video:






As you can see, it is not original enough to make a really nice restoration, though I originally planned to fit it up. Then I bought an ebike, and in studying mods and things I realized I have a perfect platform for conversion. I stripped it down to the bare chassis, and then stripped the paint and did the bodywork in prep for the conversion.





A little bodywork:







Paint will come after the final fab for the electric conversion.

Since the engine is the swingarm, I have to fab my own. After several mock-ups, this is what I have settled on:


I will weld it up after I receive the 4KW hub motor.

Speaking of parts, this is what I have ordered so far:
HWZ Series DC/DC Converter 96V to 12V
* ebike throttle
* Electric Motor QS Motor 10inch 205 4000W 72V 85km/h
* Brake kit
34ah 72V battery, custom made
Display, controller
J1 Cable
2*x CNL 500A Fuse
Emergency Contactor KEMG-125A 125A continuous
KBL/KEB J2 Cable
* Kelly Sine Wave Controller KLS7245H with IP66

While I wait for the slow boat, I will finish the bodywork and prep for paint, which will come after I finish the fabrication and install of the conversion.
 
That’s a big battery you’re using, what kind of charger are you buying?
 
Ready for primer. I can't go any further until I receive the primer. I wont paint it until I have all the electrical in place for fit. I may need to do some more fab. Next up the front suspension and rear shock. I have a new handlebar holder and cover, so minimal work there.





 
Back in the mid 2000’s I knew a guy in Portland who tried to make an electric scooter. The tech wasn’t quite there to make it work. This should be interesting.
 
The wiring on the scooter will be all new. This is my current (pardon the pun) take on it.

For the motor, battery and controller electrics:


For the scooter electrics:


Motor electrics borrowed partly from the internet.
 
Thanks again to Resistor for helping me work through the motor wiring. I think I am getting close. I completely redid the motor diagram, and updated the bike wiring. I am using a new fuse block, and completely hand wiring the bike. I plan to reuse the switches as much as possible, and adding a device that will translate the throttle cable to electrical impulses to keep it stock as possible looking. The clutch lever will be repurposed, or replaced, with a rear disc brake set-up.




Just waiting on all the parts to come in. So far I have the Inverter, 72V to 12V 25 amp, the main battery cut off, and the amp/current meter in hand.



Battery should be here this week, and the motor and controller plus brake mechanicals next week.
 
Got the battery today, thanks Raymond, and the charger, thanks Amazon, plus a fuse and the LED flasher.

Battery was 73.7 volts tested, popped it on the charger to make sure it would charge, looks OK!








These will be welded, carefully, into the swingarm for the pivot bolt.
 
The battery was a very tight fit, so to remedy that I notched the frame to allow for the battery to sit low enough. I used 1" angle, and welded it in. Then more in front welded in with a support. It fits now, though still tight. I will ensure a properly set-up suspension adding 1" height and stronger springs for my fat ass.

Please realize the shape of the body, and the mismatched metal thicknesses mad pretty welds not so easy. I will be sealing up the gaps to make it water tight, but not until I am done with all fabrication.











I will also add a double layer of battery shrink wrap for protection. The gap is literally 1/8" all the way around. Tight fit. I will also add 1/8" nylon base plate, and a battery strap.

This long weekend should allow me to finish fabrication, prime the body and fab the swingarm. Fingers crossed.
 
A few more hours in the garage and the swingarm is at 80%. I have to wait until I get the motor before mounting it and placing the shock mounts. Plus I need to relieve the drop=outs and add pinch bolts. But, overall it is near final form.

Ignore that crappy welds. They are not pretty, but they are very solid.









I didn't think the workshop could get more dirty, but I was wrong.
 
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