Hello to All, new electric biking.

[Rich H]

Very glad I found this forum as I'm completely new to electric bikes, I had never even tried one out. A neighbor at our storage unit was putting 2 bikes away for storage before selling. I tried both out in the lot and bought both as the price seemed very low and one of the bikes only had 9 miles on it (it was for his wife and she couldn't get used to it I guess). The bike that this man was riding is a 2018 (I think) Biktrix Stunner LT with a rear hub motor. I checked it over at home and tightened some loose bolts but otherwise it looked in great shape. On my first 5 mile try out ride I noticed that when starting from a dead stop the pedal assist kicks in for a second or so and then kicks out for a second, then back in. It will do this 2 or three times before staying engaged. I was able to get info from Biktix website and made sure all the settings on the LED display were at factory settings. I got an email contact going with Biktrix tech support and they suggested taking out the battery, press power a few time to be sure there is no power left, disconnect every electric cable I can access and check for dirt and or damaged pins. Then reconnect everything and try it out. Now, I still have the same problem and a few new ones. As of now the throttle only gives walking speed power and the pedal assist level will only go up to 3. There is only one Biktrix dealer in Florida, about 130 miles from me. They suggested that I keep working with Biktrix tech support and try to find a bike shop closer to home that can work on any electric bike brand as many have the same operating parts. As a last resort I can drive it up there for service. I could use some good advice if anyone has had similar issues with a Biktrix rear hub motor or other brands as well. BTW the other bike I bought is a Rad Power, RadRover ST1 with 9 miles on it and it works great, no issues.
Thanks and a Happy New Year too!

 

[indianajo]

Welcome to the site.
One usually debugs by replacing components. The contact cleaning routine biktrix suggested to you is cheap and a first step, but didn't yield any results did it?
It is possible your PAS pickup is too far from the magnet wheel and only picking up some of the magnets. Check to make sure the magnet wheel is straight, and the pickup is one paper sheet thickness away.
It is also possible your battery has bad welds or something and can't support loads. I tested 3 batteries with 10 ohm 750 watt load resistors and a voltmeter until the third one didn't collapse the voltage under 5 amp load. Got the money back from Amazon for the first, not from ebay for the second since it took more than 31 days to get it back to town & tested. The 3rd from Luna is fine. He has left the 48 v battery business. (52 v batteries are for desert racers IMHO).
There is nothing special about a biktrix rear hub motor versus others. If above didn't help, I'd start by buying a new PAS pickup with the same connector, & replace it. If that didn't work I'd buy a new controller with same connectors and see if that helped. Easier said than done. My best source of individual ebike parts has been ebay and the pictures are so bad you can't tell much. Most new controllers would come with a throttle that would be unlimited in speed, probably.
The best way to get a motor, controller, PAS pickup & magnet wheel, throttle, brake handles, display, battery that all match, is buy a new power wheel kit. About $330 these days without battery. If you live in US, I suggest ebikeling. Some people have said nice things about leaf. Then the warrenty belongs to you, not the previous owner. (As a second owner, biktrix owes you nothing IMHO). The connectors may not match what you have going through your frame and would lead to messy wiring tie-wrapped to the frame. I ride a bike like that, about 7000 miles electrified so far.

 

[PedalUma]

@Rich H,
You have three things going on. 1) Erratic behavior of pedal assist. 2) Anemic throttle response. 3) Only three accessible power levels. Let's assume the three are related and there are not a mechanical issues or poor connections. If we go with that assumption, you need a new controller. I see two options and both require removing the existing controller. You can remove the controller, tagging the connections, photograph it, and try to find a replacement online. Or you can email Biktrix and have them send you a replacement for a fee.

 

[Rich H]

Both good suggestions indianajo & PedalUma. I last contacted Biktrix tech support on Friday night so I'm going to wait till Monday or Tuesday and see what they say. I have checked the PAS pickup when I got the bike. It was about 3/8" away from the wheel so I moved the magnet wheel about 1/8" away from the pick-up, keeping it straight. I will try moving it closer and of course would love it if that helped but, I think you are on to what I need PedalUma. I don't think I did anything to damage the controller as I followed Biktrix instructions. The bike actually changed again when I retried the connector instructions. This time I lost the headlight as well. After doing it again I'm back to what I described in my first post. One other thing I forgot to mention is that the LED display has frozen up on me a few times as well. Couldn't even shut it off until I made several attempts. And yes, as the second owner Biktrix owes me nothing, but they do seem willing to help. I think knowing the first owner has a lot to do with that. And if I take it 130 miles up the road to the only Florida dealer, they have already told me it's $75 an hour for labor. I've called two local shops and neither one wants anything to do with an electric bike that they don't sell.
I'll keep you posted.

 

[Rich H]

As an update to this, I was able to get the bike back to operating the way it was before I had tried unplugging all connections. The PAS was just set wrong, but I was able to get the throttle back by flicking the brake handles each a few times while flicking the throttle. Don't know if I just got lucky in resetting things or if I still have a problem. Biktrix tech suggested starting by replacing the throttle and the display. I will do that and see what happens but as of now the bike works well except for the cut out/back in of pedal assist when first taking off. You can hear the power cut out and back in. It sounds like an old 3 speed standard transmission car taking off. Maybe it's normal, to keep the rider from over doing it when starting since it is a powerful bike.

Thanks, Rich