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[Jreigner]

Hello, I'm new to the forum and have come here for help. Ive recently bought a seized 97 gsxr750, deiced it and put an ME1004, alltrax 48300 controller and 4 12v 50ah sla batteries running 16t/76t sprockets. My reason for being here, aside from a love of ev vehicles is because this bike is dog slow. Are my batteries killing me or is it the 400lb bike? I'm 250 on top of it. I'm sure I've left out more details to help figure this out.

[TheRan]

It's not the weight, it's the controller. That limits you to 14-16kW which is barely more than a decent 125cc (around 11kW) and the engine that was in the bike put out 95kW. Swapping out the controller the motor would be capable of peaking at about 19kW for 30 seconds (just under 10kW continuously) so that's also going to be a limiting factor. No idea what the current draw limit is on the batteries but if you've got the room you can double up and run them in parallel (2x4) to double the current, or if you can get a higher voltage controller and motor you can get more power from the same current.

[Demoni]

Sounds like a cool project!
It's never going to be a rocket ship but there are things you can check to make sure you are getting the most out of the parts you have.
First 2 things to look at are the battery and the gearing.

Battery
You mention you have 4 12v batteries, are the wired in parallel or in series? I'll assume they are in a 48v configuration.
As the controller is rated at 350A (peak) providing it with 48v will give you a max output to the motor of 16.8kW. Even at the continuous output of 300A you will still get 14.4kW.
That's above the motors continuous rating of 8.2kW but a bit short of the max of 17.1kW.
Everything else being perfect you could get a bit more power by going to a different controller.

However I suspect the battery pack is unable to provide the power your existing controller is capable of. It would be worth measuring if the battery can provide the required current. In addition knowing how much the voltage sags under load.
If the battery is only able to provide 200A and each cell sags to 10v under that load your controller is only getting 8kW.


Gearing
I just checked the Zero Fx specifications for a comparison.
The FX motor is rated for 20kW @ 4300 rpm, they are using a gearing ratio of .2 (18/90) pushing a 250 lb bike.
Let's say the GSXR is providing 10kW. That power is being sent to the rear wheel with a taller ratio (.21) pushing a 400 lb bike.
A lower gearing ratio would go a long way to making the bike more enjoyable. Again it's not going to be a top speed bike but it should pull stumps at low rpm.


Post some photos would love to see it.

[Jreigner]

Thanks for the replies. It sounds like my motor/controller combination is underwhelming for this. What do you recommend? Im not too worried about top end, 40-50mph would be fine. Is my gear too tall? Should I go back to the stock sprocket (45t)? The batteries are wired in series for 48v. The bike is definitely a good donor - nice and ugly but mechanically there - and for 100$ i couldn't complain. (plus I got scrap prices for the removed stuff) Once it gets working, Ill clean it up. Ive built smaller bikes for my sons on the razor rsf650, topping out at 40mph - this is like this but just way bigger.