HyperScorpion with wacky speed readings and bad motor knock, diagnosis please

[BenE]

Mystery problem! My HyperScorpion -- now 2,000 plus miles old and never crashed -- had an intermittent problem where the speed reading would jump around wildly and mess with peddle assist (unless I was in R mode). Juiced support suggested replacing the controller, which I did carefully last weekend. But the wacky speed readings remain AND now there's a loud knock coming from the motor. Is the new controller defective or was the problem something else all along. Juiced has not responded with their diagnosis and I'm totally baffled about how to proceed. Suggestions are most welcome.

 

[BenE]

Well, now Juiced tech support thinks the speed reading problem is in the rear hub and has offered to refund me for controller replacement. It's going to be interesting to see if swapping back to the old controller eliminates the terrible motor knocking sound.

 

[BenE]

I don't know where you are thinking of going - but a "controller" does not cause mechanical sounds - it's the motor making that noise - and YES IT'S BAD.

My "guess" is that the plate mounted planetary gears in the hub motor are mashed up and need to be replaced - and you will need to remove the rear wheel - pull the cover of the hub motor from the disc brake side - pull the stator - remove the "old" gear plate - clean the inside of the housing - install new gear plate - lubricate those new gears - and zip it back up - and you will be ready for your next ride and good for another 2K miles. Have Juice send you a new "gear plate" and hop to it buddy !

Thanks, fabbrisd. In fact, now I've got the rear wheel off and plan to open up the motor as soon as I can get the FR-1.3 Freewheel Remover I think I need. Or do you know another way?

BUT there's this: When I put the original controller back in, the knocking sound completely vanished. I even did the controller swap twice more with the same results. So while the knocking sound seems very mechanical, it goes away completely when used with the original controller, no other changes.

But then again, neither controller makes the bike work right. On the original, the speed readings still jump around wildly from 0 to 45. On the new controller, the speed readings change more smoothly but still seem high (though hard to tell because it's on a stand). And on either controller, the motor only runs for a short time before the throttle goes dead and stays dead unless I let the bike sit for 10 minutes or so. PAS doesn't seem to work at all, either controller. All connectors look clean and straight, including the six in front of the handlebars.

 

[BenE]

So I opened up the HyperScorpion motor and there's no visible damage to the gears or anything else. No corrosion either and still a reasonable amount of lubricant after 2,000 miles plus.
The pins on the motor connector also look good but I guess the wacky speed readings problem could still be in the hub. Suggestions on what's wrong with this bike are welcome, though I am pursuing solutions with Juiced tech support.

Incidentally, the HS gear plate can not be accessed by simply removing the motor cover on the disc brake side. The cassette and its three nuts have to come off so you can drop the motor and gear plate out of the hub.

 

[PCeBiker]

I'm thinking that you might have a faulty speed sensor, or a bad connection.
If your motor has 9 pins, then your speed sensor is inside the motor.

If the speed sensor is faulty, the controller may get confused and not deliver power properly.

That could explain the knocking but it's strange that the replacement controller knocks and the original doesn't. Perhaps there was a software change? Does the replacement controller have the same model number on it?

There is a tester available to check the circuits in the motor, and I think that you can check the speed sensor with a regular multimeter?

https://a.aliexpress.com/_mMoUVQE

 

[BenE]

I'm thinking that you might have a faulty speed sensor, or a bad connection.
If your motor has 9 pins, then your speed sensor is inside the motor.

If the speed sensor is faulty, the controller may get confused and not deliver power properly.

That could explain the knocking but it's strange that the replacement controller knocks and the original doesn't. Perhaps there was a software change? Does the replacement controller have the same model number on it?

There is a tester available to check the circuits in the motor, and I think that you can check the speed sensor with a regular multimeter

Thanks, PCeBiker. I think you're right about the Hall (speed) sensor but using that tester and then fixing sensors as necessary looks beyond my skill level. Also, Juiced gave me a slight discount and 30 day return option on a new HS rear wheel assembly. If it works right, it will be an expensive and crude fix for what may be a small electrical problem, but I'm hoping.

 

[BenE]

Thanks, PCeBiker. I think you're right about the Hall (speed) sensor but using that tester and then fixing sensors as necessary looks beyond my skill level. Also, Juiced gave me a slight discount and 30 day return option on a new HS rear wheel assembly. If it works right, it will be an expensive and crude fix for what may be a small electrical problem, but I'm hoping.

PS: The HyperScorpion motor connector has 11 pins, by my count, and I suspect that one issue with the tester is figuring out which wire is which.

 

[PCeBiker]

Thanks, PCeBiker. I think you're right about the Hall (speed) sensor but using that tester and then fixing sensors as necessary looks beyond my skill level. Also, Juiced gave me a slight discount and 30 day return option on a new HS rear wheel assembly. If it works right, it will be an expensive and crude fix for what may be a small electrical problem, but I'm hoping.

I'm guessing that a new gear assembly will fix your problem and you'll have two controllers that will work for your ebike.
If all the motor cable wires connect to the gear assembly, (and nothing connected to the outer housing,) then it should be a complete electrical swap.

 

[PCeBiker]

PS: The HyperScorpion motor connector has 11 pins, by my count, and I suspect that one issue with the tester is figuring out which wire is which.

View attachment 162962

That's a bit different than my motor cable and the KT controller that I installed.
My rear hub motor has 9 pins, and the only other pin I'm aware of is a motor temperature sensor pin.

Perhaps your controller is doing more communicating with the motor than I'm aware ?

I wouldn't call the replacement wheel assembly a crude fix, just probably overkill, and you should have essentially a brand new motor.

 

[BenE]

Happy to report that my HyperScorpion is running very well with the new rear wheel assembly. So it seems evident that the wacky speed readings and related issues -- even the mechanical sounding knocking with the replacement controller -- were all due to motor electrical issues, probably Hall sensors. I'll add that Juiced's rear wheel assembly is exceptionally complete -- right down to cable ties -- and seems quite reasonable at $525 total including shipping and tax.

 

[PCeBiker]

It's a good thing that they had a replacement wheel for you.
It sounds like it's proprietary.

Too bad that the original didn't last longer.
2000 miles isn't all that many miles.

Maybe you can fix your old motor now that you can use the new working motor as a reference?

 

[BenE]

I agree that it's disappointing to have a major fix at 2,000 miles, but will add that this specific problem seems quite rare as best I can tell from the various Juiced forums.

As for the old motor, there's a young bike whiz in my neighborhood who may enjoy messing with it...