Levo Gen 3 Turbo Levo Gen3 inconsistent power

[jeffintheusa]

I am finding that the motor support on my bike varies without changing the settings. What I mean by this is when accelerating I feel variation in the amount of 'push' provided by the motor. It is noticeable on the trail and very obvious on the road, when accelerating up from say 7 MPH up to 12 MPH. Sometimes it feels like the bike will take off on you, and then other times it feels lacking in power. Testing it out on my street I did 20'ish acceleration/brake/accelerate cycles and probably 50% of the time I could feel the motor was not providing full support. In mission control I have acceleration set to 100%. I did this road test in Turbo mode which is set to 60% support, 100% peak power.
I have also noticed that on a very rare occasion the 'overrun' of the motor is longer than usual and it can be quite scary. It can last ~2 seconds instead of the usual ~0.5 second.
I also have a Turbo Levo Gen2 and it is extremely consistent in the way the motor torque is applied during repeated acceleration tests and I have never had the extended overrun situation occur.
Has anyone else experienced something similar?

 

[James_C]

Yes, motor was failing, sprag clutch failure to be more precise. Something to do with the torque sensor not registering the speed or something.

Have a look at "ebike motor centre" videos on youtube, and their website. Lots of explanations about what to check for.
If its out of warranty, I would suggest get it fixed and not wait for it to completely fail as it will cause more damage and cost more.

 

[jeffintheusa]

Thanks! I grabbed the info below from their site. I definitely feel something strange through the cranks when the excessive overrun occurs. I would have described the feeling as something getting stuck/jammed which matches up with the information below.

My motor runs on when I stop pedalling
This can be one of two reasons:

1. The crankshaft needle roller bearing is badly seized, breaking up or contaminated. This causes the crankshaft and sprocket carrier (torque sensor) to become one or very stiff to turn independently of each other.
2. The clutch bearing is starting to fail and the ‘sprags’ (small feet that lock the bearing) are beginning to jam or stick. Both these scenarios allow the motor to continue to add power because it can only see that the crankshaft is still turning. This may happen right up to the cutoff speed.

 

[kawamaha]

My motor runs on when I stop pedalling
This can be one of two reasons:

3. torque sensor failure.

I had this problem but changed the torque sensor and a sprag bearing, so I don't know what caused this...

 

[Troutwrestler]

I find the over-run on the Levo always to be more than the 0.2s that is specified. I actually find over-run extremely annoying and totally raised an eyebrow when, someone, I think Bosch, added longer over-run as a "feature".

 

[RebornRider]

When my sprag clutch was failing, I would get lengthy overruns (a second or two), and sometimes I would get far more than the expected assistance when climbing. It felt like I was being towed up the hill. My motor was rebuilt by BearingMan's USA affiliate. He said the crank shaft was badly corroded, which was hard on the sprag.

I think what was happening is that the sprag was not releasing, so the torque sensor, which is supposed to monitor only rider input, was seeing motor torque input. This made the controller think I was pedaling, when in fact it was just motor torque reaching the torque sensor. The motor would continue propelling the bike until the sprag clutch let go.

The overruns and tows are gone now that the motor is fixed.