8fun motor and unknown controller worth saving? (A shittii ebike story)


100 mW
May 10, 2012
The motor and controller in question came off of a Bullshittii (Busettii) ebike that my neighbor bought new several years back (I wish he had talked to me before he did! I don't even want to mention how much he paid). I believe this motor was rated at 350W but the motor is labeled with a Bullshittii specific part number so I'm not sure.
He barely rode the bike because it was a total POS even new then the shittii battery went bad, so it sat in his shed since 2012-ish.

Recently he gave the bike to me so I figured I'd try to see if I could get it to work with a new battery. I swapped the battery connector to match the good battery and it spun up the poorly-laced wheel on the stand just fine, so I taped the battery to the rear rack and geared up for a test ride. I made it about 2 feet before the the wheel fell off because the axle spun in the dropouts. :lol:

Unfortunately it also spun the tabbed washer on the axle on the disk brake side which damaged the axle threads in that spot. However, I still wanted to test it out to see if the electrics might be worth saving, so I pulled off the ruined tabbed washer and temporarily ghetto-installed a Grin V2 torque arm that I recently bought for my fatbike project (that I'll start a build thread about later) and I geared up again. The motor held on this time and amazingly, with a half-charged 48V battery and the 48V 25A rated controller, the POS bike made it up to 20mph (GPS). It was sketchy as hell at that speed, but I was still grinning like an idiot! :D So naturally... I had to fully charge and rig up my stout 52V battery to see if I could blow something up or crash trying. :lol:

I was shocked to find that not only did the little motor handle way more than it should, but on the full charge it held 25mph! I ended up riding, amusingly terrified, at over 20mph without pedaling for the better part of 12 miles before I got home and realized that a rear spoke had snapped somewhere along the way. :shock: I called that a lucky success and put it away.

This morning I pulled the electrics (and my torque arm) from the POS bike and opened up the motor. Much to my surprise, it looked very good inside as far as I can tell, so I put it back together. Unfortunately while removing the inner nut on the disk side, I had damaged its threads when I backed it out over the damaged axle threads. The outer nut was already damaged from earlier. Neither of those hurt the axle threads further, so obviously the axle is a lot harder than the nuts. I un-laced the bent POS rim from the motor and inspected its spoke holes. They are ever so slightly ovaled, possibly because the spokes were too small from the start (good job Bullshittii).

So, my thoughts are as follows... tell me if I'm not thinking straight:
If a die is run through the damaged part of the axle to remove the buggered threads and the two nuts are replaced, then this motor should be okay to re-lace into a good rim with proper sized spokes, if the slightly ovaled holes won't cause problems (will they?), and the tabbed washer can be skipped if a torque arm is used on the outside.

The controller label is half missing/unreadable so I'm not sure what controller it is, but I can see its rated for 48V and puts out 25A. It didn't miss a beat during my thrill ride so I'm assuming it's worth using again. However, I don't think that motor would last too long with that controller so I might use that my 20" folding bike with an appropriate motor for that (maybe a Mac 8T... the bike does have 135mm dropouts).

I really don't know what to do with the motor, but if it can be used after something as simple as cleaning up some threads and new hardware, then I'd hate to throw it out with the rest of the Bullshittii bike because it works beautifully in brilliant silence, and it impressed the hell out of me.

Let me know what you think.

I'll load up some pics in the follwing post(s).


  • 20191228_154213_compress25.jpg
    477.6 KB · Views: 612
  • 20191229_123934_compress9.jpg
    433.3 KB · Views: 612
  • 20191229_143656_compress37.jpg
    236.3 KB · Views: 612
  • 20191229_143616_compress18.jpg
    287.5 KB · Views: 612
  • 20191229_113643_compress4.jpg
    314.9 KB · Views: 612
The grease in the motor with the gears isn't black or burnt like it looks in the pic, it's solid green, not burnt at all. Just a bad pic.
I un-laced the bent POS rim from the motor and inspected its spoke holes. They are ever so slightly ovaled, possibly because the spokes were too small from the start (good job Bullshittii).
It's normal for spoke holes to shape themselves to the spokes, so "ovaling" may happen under perfectly good wheel builds.

It can also happen becuase spokes are the wrong size, but it's actually not because tehy're too small, it's because they're too thick, and can't be tensioned sufficiently without cracking the rim (which loosens the spokes, and lets them move around in the holes).

If the holes in the mtor are too large for normal (14 or 15g) spokes, you can use washers; these are actually made for the purpose (spoke washers) or you can use what you can find in a hardware store if you have to.

Thinner spokes are better, they make a stronger wheel because they stay tensioned at a level that doesn't damage the rim.

Thicker spokes take more tension and if too thick the tension required is so great it breaks the rim, small cracks around the nipple holes (which you may not even see) loosen the spokes, and the wheel comes apart over time, or breaks spokes at the J-bend at the hub.

To use thicker spokes you have to use a heavier duty rim made specifically for the thicker spokes, and then tension those spokes sufficiently for their thickness.

Most ebike wheels use too-thick spokes (12g) already, so using thicker ones means having to use motorcycle rims to keep from destroying them.

The controller label is half missing/unreadable so I'm not sure what controller it is, but I can see its rated for 48V and puts out 25A.
Well, that's 1200w, so it would destroy a 350w geared hub if used anywhere near that max for very long (I've done this....hot enough to melt solder inside it!). If 25A is a peak, and 12A is the continous, its' still 600w, which is still twice what a 350w geared hub is meant ot take continuously, so it can be overheated and damaged eventually. (I broke a clutch in one like that, and browned it's windings).
FWIW, that motor, if those ar 26" wheels, looks more like the size of the Ezee or MAC / BMC motors, which are nominally 500w, and have been pushed over 1000w for various periods under various conditions.

It's probably a decent motor. If I had it I'd probably stick it on the Raine Trike I built for my brother, to make 3WD for it. :)
Yeah, it looks like a BMP;
It's a 5 Kg geared motor like the Ezee, Mac, BMC, etc. Maybe not quite as many design features as those, but a nice motor never the less. Been around a long time.
The speed/volts ratio listed leads me to believe it's a mid Speed "260" (260 rpm rated @ 36V) which is very useful for 24" and up wheels.
The controller is nothing special, square wave, probably has cruise, 3-speed limiting and PAS. If nothing more is wanted, it's probably a fine controller. Well matched to the motor as I think the "350" motor rating was thought up by a lawyer.
I would use that stuff, but geared hubbies run on square waves are my thing.
Most folks would probably want a sine wave controller and controllers are the least expensive and easiest to change of the main components.
Thanks for the info, guys. Sounds like I was right in that it should still be perfectly usable despite the damaged axle.

Yeah, it was a 26" wheel.

I was thinking that it's a "350W" version because of the width. The 500W versions seem to be wider. However, I was only going from pics so I could be wrong. I'll have to read that BPM thread fully when I have a chance. Thanks for the link.
Either way, yeah... it certainly handled a lot more power than that for the short time I was messing with it. My 52V battery (14S5P) is a Jumbo Shark from EM3EV with HG2 cells, so not much sag at 25A. I figure that at full charge I may have been hitting it with as much as 1300-1400W, and I even rode up some hills at 12-14mph at WOT and it didn't blink an eye. It was close to pulling the front wheel off the ground from a stop (helps that all the weight was in the rear). For that 10-mile ride the other day there were lots of people on the trail so I slowed then accelerated under full power a lot. I thought I would end up pedaling or walking back, but I just ended up super impressed (not so much with the poorly assembled Costco bike that Busettii put it on).

I'm trying to figure out what to do with it still. I have a Downtube 9FS folding bike that, back in 2012, I put an old 500W Heinzmann brushed motor on (from an early 2000's EVG Ebike SX). I never finished it because I left the job that I was going to use it for to get around the campus, so I just gave up and buried it (shouldn't have). That setup is 90% installed. I have a battery for it now so I'm going to finish installing everything and see how it runs. If my calcs are right, on 50V max (50V components in the 36V controller) in the 20" wheel, that should top out at about 18mph. If I don't like how it runs or blow it up then I could have this BPM laced into a 20" wheel and use the matching controller. However, while it'll have hilarious torque, it should only go about 19mph based on the speed it ran in the 26" wheel. Not much improvement. :? It would certainly be more efficient than the brushed motor, though.

Originally I wanted to put it all on my wife's old Raleigh XC bike (Made in USA! Yeah, THAT old, haha). However, that setup is way too twitchy for her and she'd want PAS which it doesn't have (although could probably be added it sounds like) so I think I'd rather get one of Grin's new refined "ready-to-roll" kits for her bike.

We have matching Catrike Roads, but I have bigger plans for those for 2020. :twisted:

I guess I'll see how the folding bike feels with the Heinzmann first. Hopefully I'll have that going by this weekend.
I should have included the earlier pic of the part number in case it may have helped with identification, but it wasn't on my mind since it didn't seem to match with anything else I'd seen. Well here it is anyway...


  • resized.jpg
    83.7 KB · Views: 544