Toby

Big thanks for all the help! It was a simple issue, but relative hard to find. One of the three cable connectors at the backend of the power potentiometer was broke. You could barley see it with your eyes. It was hard to find since I had the impression if you pull out any of three potetiometer cables it will always go by full value. This is not the case. When I pulled Speed and Response (with full set on the limit) the bike went down to almost zero in speed and response. But with full set on the limit for Power nothing happened when I pulled the cable. Thats how I figured it out. If anyone else have the similar issue.

I will do some test with an voltage tester this weekend. But please help me, how do I test the voltage going to the motor at full throttle? How do I adjust the motor controller, it is just a black box? So you do not think it is any issues with the controller it self?

How do I check if the speed dial is defective? He uses it more as a MX bike in the backyard track.

What is the commutator (main body?). Since the bike is strong in response and power. Could it be the controllerwhich is broken?

Yes, it is on max. Also tried to unplug it (thought it will go on max all the time). But then the bike barley moved forward.

My son (8 year, 30kg) rides MX but also has an Oset 20.0 R for technic training at home. It is a MY18 (bought 2019). We are the 2nd owner. I didnt reflect over top speed when I bought it because I didnt knew how fast it should go and had no speedometer. I have had a feeling during the whole Spring that something is not right with the speed. It only goes up to 21km/h while it should be speeding over 50km/h. The bike feels very strong, both when it comes to power and response. But I have nothing to compare to, so maybe it should be stronger. What I have done is, bought new batteries (it didnt help). I also screw down and put together the whole bike (and opened the dc motor) but nothing helped. So now I really need your help, expertise and support. Have you experienced the same issue before? Is it something I can do by my self? Or is the DC motor broken and need to be replaced? It should be mentioned that no strange sound is coming from the bike or motor. Any help appriciated!