Super73 S1 Rebuild

Hey all, this is my first post after having lurked this forum for years - glad to be here

I have a Super73 S1 that I love dearly:


I've taken it off road and as a camp bike:


I would like to (instead of a ground-up build) heavily modify this vehicle to just ... improve it. Hopefully that's cool with the group.

The goals of this build, in order of priority:
- more power
- better throttle response
- better performance/comfort off road
- better range
- looks totally sick

Let's get started.

The first priority is MOAR POWER.

I like ASI controllers so I'll put a BAC855 into this puppy. The creme de la creme:


Batteries tend to be a limiting factor so I'll upgrade but not build my own this time:


Not trying to shell out the money for another motor, so I'm hoping the added (and tuneable) power will be adequate. Honestly I don't have hard success metrics for this project, so I'm relying on the butt dyno.

Next steps are videos to compare side by side on the bench, and tape mounting to compare with ride testing!

I have the BAC855 running sensored on the stock motor!

Original S1 powertrain on the bench:
https://youtu.be/saW0v15OO8U

BAC855 powertrain on the bench:
https://youtu.be/hCNC2KPupQA

I have space to mount both batteries and controllers to the vehicle so I can do a very direct 1:1 comparison on the ground as the next step.

Alllllllrighty. I think I broke my motor! Only a few short rides after controller tuning. Here are my symptoms:

- When I go into BACDoor and run motor discovery 2, the motor now sounds like this: https://youtu.be/Qn0V9uKQxvo
- Under throttle and spinning in the air, the motor doesn't make that sound
- Under throttle but with weight, the bike won't move and the controller throws a "phase overcurrent" error
- If I connect the stock controller and battery, the bike feels the same and doesn't make that sound

That last point is throwing me off a bit, but I don't have visibility into the stock tuning specifics and am okay assuming I don't know something about the stock tuning. All other signs (in my head) point to something shorting or getting to an "arc-able" distance inside the motor.

Didn't I say in the last update that I didn't want to shell out money for another motor?

If the motor runs fine with another controller, the motor is fine. Did the controller reset or burn?

Vbruun said:

If the motor runs fine with another controller, the motor is fine. Did the controller reset or burn?

Click to expand...

The controller reset.

I was initially also thinking the motor is fine since it runs normally with the stock controller. However, I'm fortunate enough to have another ASI controller so I installed it and flashed it to a parameter file that I know worked fine before. The motor discovery step was clunky/broken like in the video, where I know it used to be okay.

Since I used a known good controller and known good parameter file, my thinking has changed to suspecting fringe damage to the motor. Of course no real way to tell without opening up the motor, but I am sending almost 3x the power compared to stock...

Whaddya think?

is one sensored and another sensorless?

Maybe there could be a hall sensor problem?

Vbruun said:

is one sensored and another sensorless?

Maybe there could be a hall sensor problem?

Click to expand...

Both sensored, and the hall table looks fine on the ASI side

handlworks said:

Vbruun said:

is one sensored and another sensorless?

Maybe there could be a hall sensor problem?

Click to expand...

Both sensored, and the hall table looks fine on the ASI side

Click to expand...

I'd be interested in finding out why the old controller works if it's also sensored, or what the new one requires that the old one doesn't in order to run.

E-HP said:

I'd be interested in finding out why the old controller works if it's also sensored, or what the new one requires that the old one doesn't in order to run.

Click to expand...

Same - I don't have visibility into the stock controller configs but I could ask ASI what they do differently from norm...

It's strange that the low power motor discoveries (sensored and sensorless) also make this crunchy sound, otherwise I would've thought it's just the power difference.

Typing this all out helps, I'm just gonna look for a new motor and bug ASI in the meantime.

UPDATE

My thinking has changed. Another project is using a CYC kit. They were affected by an ASI recall and couldn't ship BAC855's - I asked for the kit without controllers, thinking my controllers were still good.

I updated to a good firmware that was sent by CYC, but the kit exhibited the same symptoms - jerkiness and unable to handle higher power all at once. !!!

I updated to my THIRD AND FINAL BAC855 and everything worked great! Ugh.

Haven't checked against the Super73 because it's a pain to remove the controller now, but this changes my thinking back to suspecting the controllers. Have a call scheduled with ASI to discuss soon.