Major quality control issues at Xiongda ( YTW-06 siezed after 1 mile )

[neptronix]

I can't believe this.. brand new motor seized after 1 mile..
Sent a message to bonnie about this and will update with the details, but i disassembled this motor to show you the carnage because i figure i won't get a proper refund..

[youtube]RKcVCfSWnKo[/youtube]

First off, you can forget removing the disc brake screws, as they open a hole in the motor..

View attachment 7

Since this thing was toast, i unscrewed the case the destructive way after failing to get enough grip to remove this with rubber..



Almost no lube anywhere.



1 screw was incredibly loose and had almost no thread lock on.. another screw had threadlock and was medium tight.. the last one..
Oh man, i really tried with my largest screwdriver in the shop. That thing is on there GOOD.

View attachment 4

Here is the baby sized stator and gear assembly.

View attachment 3

The metal shaving crop inside the case was pretty plentiful.



Multiple stripped screws from the factory, plus some questionable soldering..



This is probably the culprit for the wheel seizing. The two sections were installed crooked. There are metal shavings on many of these long screws have strips of metal and/or shavings on them. I know what this means.



A couple other notes..
If you move this motor side to side, you can hear things knocking around inside. It did this before the first mile.
There are no spring washers on the outer ends of the case to prevent this kind of knocking about ( MACs have this )

There is play in the axle. I believe this is a 2 piece axle design, like the Bafang G310. The link between the two axles is 6 screws that are pretty thin. I doubt there is enough metal contact to prevent the axle from bending over time or during a harsh impact.
Mine appeared to not be straight right out of the box, but it was hard to eyeball it..

I had to shave the axle nut down so that it fit in a 135mm dropout with minimal bending of aluminum chainstays. The axles are perfectly 135mm wide, but the axle shoulder is improperly machined ( tapered, not flat ), and a 7 speed freewheel will contact the frame if you do not use the included nut.

The axle nut will probably sit at an angle. I hand filed it to within +/- 0.5mm flatness and it managed to damage the threads on the hub anyway.

So i would not buy this motor even if you manage to not get one that's 'built on a friday' like mine.

 

[neptronix]

Side note, looking at a picture from pedelec.de, it looks like some circular tubes were meant to make the fitment between both sides of the axle very solid. Xiongda failed to install these on mine.

 

[neptronix]

No reply from Bonnie yet.
I notice the YTW-06 is no longer listed on their alibaba page..

It was on alibaba before i sent a message..

 

[neptronix]

Okay. So i finally got mad and submitted a paypal complaint.
I get an email back from "bonnie" saying that the other employee quit due to eye problems and their engineer will look over the pictures i submitted.

Looks like the eye problems stop when you call the cyber police. :lol:

Will update with the result.

 

[Jean]

Very interesting post because i hesitate for so long time to buy this ytw06 or not. The problem to me is the noise and the drag. But your problem seems to be really extraordinary. I hesitate with another little engine called jiabo JB-75 T2. I think it's more confortable even if it's a little heavier. I hope you will publish the end of your story.

 

[neptronix]

Hey man.

I ordered up a bafang G310 from ebikes.ca and there is significantly less drag than when i first spun the YTW-06 by hand in a spoked up wheel.
My motor was EXTREMELY draggy over the 1 mile i pedaled it at, but it was also in the process of seizing up, so i cannot really compare the drag to other motors.

As for Xiongda..
They say they're going to send me a new motor, but they are taking their sweet time. Not sure how it will go.
Another member here says they are not responding to sales requests via email.

 

[neptronix]

Just some follow up..

After an entire month of waiting and email tag, i got my replacement motor in, free of charge.
Per my request, the vendor provided a tool for opening up the motor. It's basically just a steel bar with two bolt holes in it. Okay, i'll take it



The new motor is the standard speed motor ( on the left ). My original motor was a faster speed, so it has a different primary gear ratio.

View attachment 1

Construction on the new motor is better, for sure. There are still signs of minor stripping on the bolts. The aluminum tubes that were placed as additional supports on the picture of someone else's motor are still missing though, which is a bit concerning.

 

[deos87]

Hi! Can anybody tell me how to disassembly the motor? Which thread direction of the external flange and does it need some special condition like an additive heat? And which grease does it need for gear?

 

[deos87]

Hi! Can anybody tell me how to disassembly the motor? Which thread direction of the external flange and does it need some special condition like an additive heat? And which grease does it need for gear?

Now I can answer. The side flange has classic clockwise thread. I have made some upgrade (see attached images) to unscrew flange. I hope that it will work. I have trouble with external bearings (6001 and 6903) they was rusted and with sun gear (it shrunk down a little). Sorry for next sentences in ukrainian, I have just duplicate information for ukrainian citizens or anybody who can read ukrainian.
Якщо кому цікаво, то різьба у цього фланця класична права. Було дуже важко відкрутити, бо жоден двохпальцевий ключ не тримав навантаження і зривався. Тому я запиляв дві лиски під ключ на 27, але він також злизував нові лиски. Відкрутив газовим ключем (або ще називають попковим). Довелося ще трошки підчистити різьбу від результатів відкручування. Гадаю, що залишків різьби буде достатньо для передачі крутного моменту з педалей. Чесно кажучи був здивований конструкції: усохла сонячна шестерня (імовірно вона і видає дивний шелест при русі накатом), не захищені від води підшипники (6903 і 6001 у мене хрустять).