New guy here wanted to introduce myself / Taco minibike project
Hello. Nice to meet you all. I look forward to picking up what I can here and hope to be able to add to the forum when I can. My first EV build is a Taco minibike that currently sports a five horse briggs. I picked up a 1204 curtis controller, a magura twist throttle, three 12 volt 20 amp hour batteries, and a used WW2 era 24 volt ball bearing aircraft starter. The fabrication and machine work will come easy it's the wiring I am confused about. I am new to the game and have little experience and no local EV pals yet. Here's a first pic for fun, I hope I have the size right. I live in SoCal.

The Curtis controller takes a 0-5k ohm input across its throttle inputs. You should get a multimeter and use the ohm setting to figure out which pair of the wires are 0-5k ohm. One pair of wires will read 5k ohms regardless of how you twist the throttle. The other two pairs of wires will read 0-5k and 5-0k ohms.
The green wire is correct but it's good form to put a switch in the middle of it. However with the low key esthetics of that bike ;-) you could just have a wire with a blade connector on the end and disconnect it each time.
As for the battery pack you've got it pretty much wrong. The way to do it is
===== +BBB- +BBB- +BBB- =====
That is ... take that blue wire going to the + of one battery, this is the positive-most connection in the pack ... the - of that battery is then wired to the + of the next battery ... the - of that battery is wired to the + of the next battery ... and the - of that battery is the negative-most connection in the pack.
The positive-most of the pack is wired through a fuse to the + of the controller.
The negative-most of the pack is wired to the - of the controller.
Something which will help is to read the install manuals for the Alltrax controllers... http://www.alltraxinc.com/Doc_Depot.html ... Yes, you have a Curtis controller, but the Alltrax controller documentation is readily available and has roughly the same connectors.
Ah.. uh.. Curtis Instruments Series Motors... whaddaya know...
Get a 700-800 watt 36v scooter motor on ebay. I've seen them for 60-80 $$
That should be perfect.
Wow, very very cool sandcasting using styrofoam. Where do you buy the materials for doing something like that? It looks like a great alternative to milling.
I love your little tacobike, by the way. Check out my own blog where I converted a moped to electric using an RC helicopter motor and parts.
Karen










Trying to figure out how the three pictured wires hook into controller. My 1204 diagrams just show two for throttle.