Motor judder like misfire.

[Wizzo]

Hi. My bike was fine for 20 miles then it started making a loud knocking banging sound then above 10mph it the knocking stopped, and now uts giving a error 7 on my sw900 screen. Meaning motor. I've tested the hall sensors and the reading from controller is 4.19volts and all the 3 wires for the return when spin wheel reads same. The phase cables give resistance when held together. So I don't know? Thanks for any help

 

[Wizzo]

The reading should be close to 5volts right. So isnt 4.19 a low volts from the controller

 

[amberwolf]

Maybe more magnet pieces have broken off?

 

[larsb]

Hi. My bike was fine for 20 miles then it started making a loud knocking banging sound then above 10mph it the knocking stopped, and now uts giving a error 7 on my sw900 screen. Meaning motor. I've tested the hall sensors and the reading from controller is 4.19volts and all the 3 wires for the return when spin wheel reads same. The phase cables give resistance when held together. So I don't know? Thanks for any help

Well, if all three halls are reading the same then they are broken or wires short circuited.
At any point in time their states should follow the commutation table below.

Time to open the motor to check it.

 

[calab]

Time to ditch the KT display and grab a generic sensorless controller along with a spare throttle, connect the cruise control wires and find a new method for pedal assist.

 

[Wizzo]

I thought magnet but if that was the case it wouldn't spin freely at 30mph without catching on them, but it's only when applying power it does it

 

[Wizzo]

I do not understand that picture. How could I test for short circuit without having to open the hub up. Using a multimeter?

 

[larsb]

If it works at low rpm then likely causes are either a hall sensor is starting to fail intermittently or the higher applied voltage at higher rpms cause a short circuit to break through.

 

[Wizzo]

Like a continuity test that's beeps the multimeter

 

[Wizzo]

No it was low volts speed, then above 20mph it stopped. And now after 10miles it won't spin for more than a second without error 7

 

[Wizzo]

How can I test them when they are in place in the hub and after you take 1 side case off the wheel lock to 1 side and doesn't spin to be to test without cover being back on. And that's how I've tested already. So please advise more. Thank you