cyclotricity stealth 250w

[tomweston]

I have purchased a used one which keeps on cutting the power off.

I have noticed that the bottom bracket is loose which allows play in the bottom bracket, main chain wheel and pedal arms. The pedal assist sensor is on the none chain wheel side as in many photographs on the web.

I have spoken to Cyclotricity technical support who suggest that the play could more than likely be causing the sensor to trip the power off and recommend fitting the sensor ring to the chain wheel side (offers protection) after replacing the bottom bracket bearings etc.
The front wheel motor spins quite happily in the air until the pedals are turned for a few revolutions then the power cuts off.

Has anybody else done this change over of the sensor ring or encountered similar power problems?

The bike is 3 years old but not had much use due to the cutting out issues.

 

[Deleted member 4366]

Does your bike have a throttle? If not, get one for testing.

 

[tomweston]

Does your bike have a throttle? If not, get one for testing.

Yes it does have the throttle.

 

[Deleted member 4366]

Does it work with the throttle?

 

[ebyk2work]

I have purchased a used one which keeps on cutting the power off.

I have noticed that the bottom bracket is loose which allows play in the bottom bracket, main chain wheel and pedal arms. The pedal assist sensor is on the none chain wheel side as in many photographs on the web.

I have spoken to Cyclotricity technical support who suggest that the play could more than likely be causing the sensor to trip the power off and recommend fitting the sensor ring to the chain wheel side (offers protection) after replacing the bottom bracket bearings etc.
The front wheel motor spins quite happily in the air until the pedals are turned for a few revolutions then the power cuts off.

Has anybody else done this change over of the sensor ring or encountered similar power problems?

The bike is 3 years old but not had much use due to the cutting out issues.

From experience: VP BB replaced with Shimano BB UN 68/122.5,measure the old and new one before fitting. And plenty of copper grease!. Check the sensor ring magnets, far better protected by the chainring. Careful with the single sensor when moving it to the other side, cable could be hardened in its position.Good luck

 

[tomweston]

Does it work with the throttle?

Yes, each time I have run it with the wheel off the ground it does not cut out which is why I think it must be to do with the sensor ring. I can not find any details of how much clearance there should be between the sensor and the ring. I am hoping to take it apart tomorrow and relocate the sensor to the chain wheel side. I have to fix the lawn mower first though.

 

[Deleted member 4366]

The clearance should be 1mm. When you transfer the sensor to the other side, you have to flip the magnet disc otherwise it'll work backwards.

 

[tomweston]

From experience: VP BB replaced with Shimano BB UN 68/122.5,measure the old and new one before fitting. And plenty of copper grease!. Check the sensor ring magnets, far better protected by the chainring. Careful with the single sensor when moving it to the other side, cable could be hardened in its position.Good luck

What do you mean by "VP BB"?

 

[tomweston]

The clearance should be 1mm. When you transfer the sensor to the other side, you have to flip the magnet disc otherwise it'll work backwards.

Thank you. I have noticed the arrow denoting rotation direction on the disk.

 

[Deleted member 4366]

The arrow has to poin the wrong way when you change sides.

 

[tomweston]

The arrow has to poin the wrong way when you change sides.

Oh, that is very important.

Thank you for your help.

 

[ebyk2work]

What do you mean by "VP BB"?

Sorry, it is the name of the original bottom bracket ( VP )

 

[tomweston]

New bottom bracket fitted, pedals much better now but power still cuts out. I suspect it must be the speed controller because if light load it runs for a long time, if heavy load cuts out in a few seconds. Sometimes the handlebar LCD power switch will turn the system back on otherwise it required the switch on the battery to be turned on and off.
Interestingly yesterday the bike was running with pedal assist and then the pedal assist stopped working whilst the handlebar display stayed on.
I have spoken to cyclotricity about this, they are going to loan me a speed controller to see if the problem goes away; very kind of them.
I am going to take the controller apart this week end to see if there is anything obviously wrong, a circuit diagram would be helpful for my older controller.

 

[Deleted member 4366]

No point in taking it apart. It's very unlikely that you'll be able to see anything that causes your fault. If the battery switches off sometimes, the fault is in the battery, not the controller.