Refurbishing A Rusted Hub Motor From An Electric Bicycle Kit

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At some point my bicycle's hub motor got rusty, probably while I was in a wetter, colder climate in which the roads were salted.

Rust had expanded the permanent magnets in the rotor and/or the laminated cores of the stator, so that to turn the wheel's axle with a wrench results in a scraping sound.

Steve Bowtie helped me by lathing off the rust that we could see on the edge of the stator. But still I hear the scraping. To turn the axle (and stator) with a wrench feels like tightening a nut on a bike wheel's axle. Clearly there is not enough clearance between stator and rotor. I wonder how much clearance there should be?

Meanwhile the axle has gotten bent a little. Hopefully there is no bend between the (sealed cartridge) bearing and the stator, though. Otherwise the bent axle may be contributing to the scraping. Can this axle be replaced? I will try to find out.

The bearings are fine, after I replaced one.

The motor apparently is a Crystalyte "408."

The kit's seller described it this way:

"Crystalyte C408R-36SLA 36V Electric Bicycle Conversion Kit

"Crystalyte kit contains everything you need to convert nearly any 26 inch mountain bike to an electric vehicle. The revolutionary brushless hub motor design results in the quietest, smoothest ride -- as well as the easiest installation! Features a brushless hub motor pre-installed in a 26 inch wheel with heavy duty spokes, double wall rims, and Shimano freewheel. Also includes battery pack, controller, and throttle. The wheel assembly replaces the bicycle's existing rear wheel, and puts much less stress on your bike while providing more power than the front wheel kits found elsewhere.

"Cruising speed without pedaling is about 16 MPH in real-world conditions. Easily reaches 18-20 MPH with moderate pedaling. Range: over 25 miles. This kit features custom-designed charger built exclusively for Discount Solar, charges form standard 120V wall outlet in a few hours. Photo shows kit installed on mountain bike; bicycle is not included.

"Features:

"Wheel/motor assembly (408 Rear Brushless Motor + 26" Double Wall Rim with Eyelets + G12 Spokes + Shimano 7-speed Freewheel)
36V Journey Rear Controller
36V Twist Grip Throttle
Key switch + 2 keys
110V AC battery charger
36V 12ah lead acid battery pack
Pedal Assistant Sensor Matching V5 PAS
Jacket for Connectors"

Sep 26th, 2017 @ 1:28 pm

Does XC have a m12x1.25 die already or does someone have one I can borrow? If so, I can send this one back, unopened, to Amazon. If not, does XC want to buy this one from me or accept it as credit toward my future dues?

The electric bike kit's hub motor was found to be seized up by rust. (It was last used in Kansas City, where streets get salted to melt ice.)

Weeks ago, Steve Bowtie helped me to open the motor, take it apart, test the coils, and clear the rust off using the lathe.

Last week or so, [Adam & Trevor], the two "ADS guys" often overhauling & improving the Bridgeport mill over the last few months -- figured out what die I need to re-thread the axle, which was mushroomed during the disassembly. I ordered it. That's the one I mentioned in the first paragraph.