Repair Motion V8 (and crash report)

[VanillaValue]

Does anyone know how to disassemble the inMotion v8? What kind of screwdriver? I already removed the side covers and the battery pack. But I need to get properly under the hood and separate the two plastic shell halves. This is so that I can reinstall the power button and leds that have fallen out of their socket. Have a look at picture for illustration of the damage and the screw I need to open. Thanks for any help!

Now for a quick crash report... I have about 400km under my belt, been riding for half a year and this is my second unicycle (first was a inmotion v3+). I've done my share of "learning crashes" and even over-leaned once (I think that's what happened).

This time something different happened. I was driving off a low curb (10cm?) on my way to work - the same curb that I've been driving off every morning for the last half year. This time however, once I touched ground the whole unicycle started shaking back and forth. Like it was shifting back and forward and not knowing whether to accelerate or slow down.  Causing a pretty violent vibration. As I was in a slope the unicycle started to gain speed and shake more & more. Then I decided to jump off and rather have the unicycle crash without me. The unicycle started bouncing and rotating the whole body around the wheel taking turns smashing the top handle into the ground or the actual wheel. Quite spectacular. No children were hurt. Plastic broke and things moved around inside.

I've been taking the subway in the mornings for a week now and am not sure whether being packed in the Tokyo subway or not being able to drive is worst. Either way; I need to fix it.

Alternatively; do I buy an GotWay ACM 16? :-D

Thanks in advance

[f0dder1024]

Found this for the V8, it's Russian with English subtitles . Google auto-translate may offer additional information. 

Edited March 29, 2017 by f0dder1024
Grammar

[VanillaValue]

Thanks f0dder1024! The video showed that there was a way to disassemble things in an orderly manner :-)

For anyone doing this in the future; the second layer of screws are insex. Picture of screwdriver and size measurements below.

I'm back on the wheel - FEELS GREAT! However, a bit wary about the unexplained malfunction so staying away even from short curb drops now. Maybe it was a black swan... :-/

[steve454]

On 3/17/2017 at 0:34 AM, FlyingFlipFlop said:

Does anyone know how to disassemble the inMotion v8? What kind of screwdriver? I already removed the side covers and the battery pack. But I need to get properly under the hood and separate the two plastic shell halves. This is so that I can reinstall the power button and leds that have fallen out of their socket. Have a look at picture for illustration of the damage and the screw I need to open. Thanks for any help!

Now for a quick crash report... I have about 400km under my belt, been riding for half a year and this is my second unicycle (first was a inmotion v3+). I've done my share of "learning crashes" and even over-leaned once (I think that's what happened).

This time something different happened. I was driving off a low curb (10cm?) on my way to work - the same curb that I've been driving off every morning for the last half year. This time however, once I touched ground the whole unicycle started shaking back and forth. Like it was shifting back and forward and not knowing whether to accelerate or slow down.  Causing a pretty violent vibration. As I was in a slope the unicycle started to gain speed and shake more & more. Then I decided to jump off and rather have the unicycle crash without me. The unicycle started bouncing and rotating the whole body around the wheel taking turns smashing the top handle into the ground or the actual wheel. Quite spectacular. No children were hurt. Plastic broke and things moved around inside.

I've been taking the subway in the mornings for a week now and am not sure whether being packed in the Tokyo subway or not being able to drive is worst. Either way; I need to fix it.

Alternatively; do I buy an GotWay ACM 16? :-D

Thanks in advance

That looks like some serious damage, even if you got it working again, did you look closely at everything before putting it back together?  That wheel was totaled.  You might want to get a new one, and write this off as a loss.  Sorry, but that is what I would do.  And you said you had dropped off the same curb many times before, but this one time the wheel acted strangely.  I think it was about to go bad sooner or later, maybe a different brand wheel would be good to try.  I would suggest sending it in for warranty repair, it sounds like some king of overspeed warning went off or something, but could have been a bad board.

If it is working well now, maybe you can keep using it, but be very careful not to go too fast, something went wrong who knows what?  I think that Inmotion has a data recorder function that might be able to tell their engineers what happened.  Could have been electromagnetic interference that day.

Are there many people riding EUC in Japan?

[VanillaValue]

Out of the 12 screws used to attach the side piece; 7 are still working. Been driving for a week now without additional incidents. I uploaded the log to the servers and called inMotion directly to get a review. They asked me to contact the seller. When contacting the seller "Electric bicycle shop" on aliexpress, they're not responding. Would love to better understand what happened.

The crash was at a relatively low speed; <15km/h. The back/forth vibration that the wheel was doing after the drop was the first and only time I've experienced it. I'm definitely more wary now when I'm driving, and especially going of curbs. If that would have happened at higher speed *brrr*

And no, not so many people riding EUCs here... Met one other person so far.

[Slaughthammer]

The shaking back and forth could have something to do with the hall sensors losing connection to the control board...

[Planetpapi]

Still under warranty but not able to get the warranty? Sounds like Ali Express/ Etc to me. Glad I bought my Ninebot and InMotion from reputed sellers.  I don't think we have any incidents similar to yours to compare and diagnose especially with InMotion V8. Happy you didn't get hurt. Also happy you are back on track!

[Jason McNeil]

On 3/17/2017 at 1:34 AM, FlyingFlipFlop said:

Causing a pretty violent vibration

On other Electric Unicycles, typically this problem is caused by the Wheel nuts—that secure the motor to the aluminum pedals supports—when they get a bit loose. These need to be very tight, at about 90Nm of force with a toque wrench.

Solid state electronics are very reliable, while it might be a sensor failure, it's quite unlikely.

Edited March 28, 2017 by Jason McNeil

[Slaughthammer]

14 minutes ago, Jason McNeil said:

Solid state electronics are very reliable, while it might be a sensor failure, it's quite unlikely.

Well, probably more of a wiring failure, as @Sidestreet Reny had recently:

 

[steve454]

19 hours ago, FlyingFlipFlop said:

Out of the 12 screws used to attach the side piece; 7 are still working. Been driving for a week now without additional incidents. I uploaded the log to the servers and called inMotion directly to get a review. They asked me to contact the seller. When contacting the seller "Electric bicycle shop" on aliexpress, they're not responding. Would love to better understand what happened.

The crash was at a relatively low speed; <15km/h. The back/forth vibration that the wheel was doing after the drop was the first and only time I've experienced it. I'm definitely more wary now when I'm driving, and especially going of curbs. If that would have happened at higher speed *brrr*

And no, not so many people riding EUCs here... Met one other person so far.

The seller probably has no idea what happened, probably they just sell wheels, if you can find an Inmotion dealer nearby maybe they could take a look at it for you.  I'm guessing the data went to Inmotion for their use and they will not respond.

What about the wheel nuts, as Jason McNeil mentioned?

Still, if the wheel is working now and you keep the speed down to a speed you can run off from if it dies on you, maybe you can still get some good use from it for a long time.

What was the wheel of the other rider you met?

[VanillaValue]

Any way to test if it's indeed an issue with the "hall sensors"? Without going off a curb repeatedly searching for a crash :-) If it's the wheel nuts, should it be easy to reproduce the issues? I'm not sure which nuts inside are the "wheel nuts" but maybe I already rescrewed those when did the disassemble/reassemble exercise.

The seller "electric bicycle shop" @Aliexpress responded and asked me if it is no longer booting; when I said it's working then they said there is no problem. I tried to explain that I was concerned about a second crash but they meant that there is no issue since it's booting up.

@Steve454 - the other rider was on an gotway mcm4. Gave me the opportunity to try it out (felt a bit too soft for me compared to V8). The other rider had been riding in Tokyo for the last 3-4 years, previously on a rockwheel. I also ran into someone riding a Ninebot about half a year ago but he looked like he was about to fall off it any second...

[Slaughthammer]

14 hours ago, FlyingFlipFlop said:

Any way to test if it's indeed an issue with the "hall sensors"? Without going off a curb repeatedly searching for a crash :-)

Open the wheel, loosen the connector for the hall effect sensors (those are the small wires coming out of the wheel nut next to the three big power wires) until maybe one (maybe all?) of them disconnects and start the wheel up. If it behaves the same way it did when you crashed, that was the problem. To avoid such failure in the future, properly secure the connector.

[Pakguru]

I was having the same problem with the violent shaking from Ford to back I took off the covers and tightened the axle screws of the wheel best description I can come up with and that seemed to alleviate the problem taking it for a test run. Okay back from the test run it worked okay will advise if there is any change in performance.