Yamaha PW-ST Motor Jerky

[E-bobby]

try removing the other end and give it a clean if still not working u need a dealer to see if it can see what's wrong and if that dont sort it new controller pcb

I did clean the other end yesterday when it was off but to be honest it was very clean just gave it a wipe, the symptoms apparently lead to a faulty sensor, I have bought a new one with new magnet and a big washer I’ll pop that on once it’s here. I don’t think it would be the controller as I have read they usually fully cut the power and don’t assist at all, also shows an error code for it being that I think, . If the speed sensor don’t work I would probably bring it to a diagnostic thingy and they would tell me what’s going on, but the flashing odo, no error code and still assisting points me in that direction. Thanks for your reply!

 

[soundwave]

bosch has 500 error codes not listed so could be anything all u can do is replace parts

 

[E-bobby]

bosch has 500 error codes not listed so could be anything all u can do is replace parts

It’s Yamaha screen and motor it’s on a haibike hardseven 7, I’m not sure if they don’t have ones not listed and I’m not even sure if they pop up on the screen because I have read they do and they don’t, Cheers

 

[soundwave]

when things get wet like wires over time it can eat its way all the way back to the pcb and damage that but if a new speed sensor dont sort it take it to a dealer.

 

[E-bobby]

when things get wet like wires over time it can eat its way all the way back to the pcb and damage that but if a new speed sensor dont sort it take it to a dealer.

Yeah I will, I do hope it is just this sensor as on my electric Carrera I had, the sensor looked brand new and didn’t have anything visually wrong, I bought a new one and just popped it in and it was working perfectly fine, this is what I’m hoping for this, cheers

 

[georgehenry]

I own a 2015 one and have found that the position of the speed sensor both in terms of distance from magnet and position it passes the sensor is critical, but once found I have had no issues in years of service and high mileage, though it sounds that you have exhaustively checked this.

Also you can get strange control issues when the battery in the display starts to run out, so changing that would be a cheap check.

 

[E-bobby]

I own a 2015 one and have found that the position of the speed sensor both in terms of distance from magnet and position it passes the sensor is critical, but once found I have had no issues in years of service and high mileage, though it sounds that you have exhaustively checked this.

Yeah, I think it is broke because I find when I turn on the bike the mileage instantly flashes, I’ve read that the controller sort of like checks everything is working before turning on, this is what causes the mileage to flash instantly. Thanks for your reply, cheers

 

[guerney]

There's a crack, possibly water ingress? Caused issues has water ingress with Bafang speed sensors reported on the forum.

Is this magnet close enough? Bit hard to tell without measurements, but this wouldn't be on my bike, I think.

 

[E-bobby]

There's a crack, possibly water ingress? Caused issues has water ingress with Bafang speed sensors reported on the forum.

Is this magnet close enough? Bit hard to tell without measurements, but this wouldn't be on my bike, I think.

I’ll go have a measure now, I don’t know why but I didn’t even think of water ingress in the crack , Update
The gap can fit 2 pound coins in but moves the spike a little so around 5mm, idk if this is too short or not. Cheers

 

[soundwave]

why not get peter to service the motor t hen it will be like new mine lasted 5 years and 1600 miles on new one

 

[chris_n]

You don't need anything other than the original spoke magnet and the sensor lined up as they should be. I don’t have my Hardseven any more or I would look and picture it for you, maybe @georgehenry could take a pic of his. Looking at the frame damage in your original picture and the crack on your sensor I would suspect the sensor is damaged.
Edit having looked again your sensor looks too clean compared with everything around it. Is this just you having cleaner it or has it already been replaced and incorrectly fitted.
Did you buy the bike not working?

 

[E-bobby]

You don't need anything other than the original spoke magnet and the sensor lined up as they should be. I don’t have my Hardseven any more or I would look and picture it for you, maybe @georgehenry could take a pic of his. Looking at the frame damage in your original picture and the crack on your sensor I would suspect the sensor is damaged.
Edit having looked again your sensor looks too clean compared with everything around it. Is this just you having cleaner it or has it already been replaced and incorrectly fitted.
Did you buy the bike not working?

Yeah bought it not working, person I bought it off suspected the motor was at fault but not sure, to be honest I didn’t clean it much just wiped it and it looked in good condition, but these sensors can do that because like I said in another post the carrera I had. The sensor looked brand new but I replaced it and it was fine, working perfectly. Also the magnet was miles away from the sensor and I think it’s damaged because to be honest half of the spokes are missing off of the back wheel . So maybe it’s had some damage to the back end of it. Cheers

 

[chris_n]

There is a manual here

YAMAHA X94 SERIES SERVICE MANUAL Pdf Download

View and Download Yamaha X94 Series service manual online. X94 Series bicycle pdf manual download.

www.manualslib.com

Chapter 2 page 30 tells you how diagnosis mode works, 2/32 tells you how to test the speed sensor.

 

[guerney]

I’ll go have a measure now, I don’t know why but I didn’t even think of water ingress in the crack , Update
The gap can fit 2 pound coins in but moves the spike a little so around 5mm, idk if this is too short or not. Cheers

There is a manual here

YAMAHA X94 SERIES SERVICE MANUAL Pdf Download

View and Download Yamaha X94 Series service manual online. X94 Series bicycle pdf manual download.

www.manualslib.com

Chapter 2 page 30 tells you how diagnosis mode works, 2/32 tells you how to test the speed sensor.

Says gap must be 10mm or less on page 59 - that wouldn't work on my bike for sure, even about 5mm confuses speed calculation bigly, especially at high speeds downhill, when it cycles from 28kph-ish to zero and back up again, over and over until travelling speed is reduced. Fine with 3mm or less. Looks like the same magnet as my Bafang kit's, must be a more sensitive sensor or something.