motor cuts out at times

Stu

New Member
I have a FLX roadster It has a Bafang 500w motor and with a 36v battery and throttle. I'll be pedaling along, no throttle just PAS and all of a sudden the power will quite and then pop back on My wife describe it has like some was pumping their gas pedal. Does anyone have a clue about what might be causing the problem we have 2 bikes and the problem is appearing on both of them. I was thinking a torque sensor Any one have a clue Thanks
 

TMH

Well-Known Member
Does it do this with a full battery, or only when the battery level is low? Have you cleaned the battery and battery socket contacts? Are the batteries a little loose or do they rattle? Have you used dielectric grease on the contacts?

I've also got a Roadster which, although it doesn't have many miles and doesn't get ridden in the rain, does not exhibit this characteristic. I do not have the throttle.

When I first got the bike I would have some issues with the display going blank, and total motor cut-off. I sprayed some contact cleaner into the plugs/sockets going into the display and haven't had recurrence of this issue lately.

Do you get the same "pumping the gas pedal" if using the throttle only? Might point more to the torque sensor if it doesn't happen with throttle only.

I had a similar issue with a Bosch mid-drive, but it only seemed to happen when the battery was 2-3 bars or lower. Cleaned everything up, but still happened some. Battery didn't seem overly loose, but I put a short (4") piece of self-adhesive weatherstrip foam under the battery and the issue has never happened again.
 

Stu

New Member
I'll try electric spray on contacts. It definitely happens at hi speed in the 20'smph and just using PAS. Even with the throttle the pumping will happen. I'll try the spray electric cleaner. Thanks
 

Stu

New Member
I think it is 28mph limit but not sure that could be it. If it is how can I over ride it
 

TMH

Well-Known Member
I think it is 28mph limit but not sure that could be it. If it is how can I over ride it
1)Turn on the bike like normal.
2) Press and hold both up and down arrow keys
3) When you get the next screen arrow down to 'Information'
4) When you get to the Information screen, I think the second line down is Speed Limit. Arrow down to it and hit the mode button
5) Mine is set at 32. Don't know whether this is mph since I'm in imperial units
6) If yours is not set at 32 (the max) change it with arrow keys
7) Press and hold both up and down arrow keys to return to main (riding) display screen
8) Let us know what you found and if it helps!
 

Stu

New Member
It didn't seem to help I brough the bike into the shop since it is still under warranty
 

Stu

New Member
I took it to the shop actually 2 bikes and neither of them acted up so in there mind there was no problem. WRONG At this point I will take it back and probably rideover about 6 miles because it cuts out more often when the engine is warmed up. The other day after putting about 6 mi on it and then letting it sit for a couple of hours the PAS didn't work at all on the ride home but the throttle worked. Yesterday I rode about 10 mi and all things worked as designed. I am leaning toward a PAS problem. I don't really know how a torque sensor works but I think that is where the problem lies.
 

ian fisher

New Member
have a look at how the battery is locked into the frame, with the battery in place, can you move it at all? the slightest disconnection is enough to cause a spark between the contacts and this will result in a power loss.