Instructables

Motorbike starter motor on a Scooter?

Hello!

I changed the starter motor on my bike some years ago, and this motor is laying around in my garage since then, working!
I always wanted to build an electric vehicle, and i would like to start with an electric scooter!

My questions are: 

1. Would the motor work and run on a scooter?
2. how much would the battery last? I plan to use a normal motorbike battery, i dont know much in electronics, they are 12V and 10-70Ah
3. will the motor heat up and burn?
4. what range would it have?

The motor in question is a Mitsuba, aftermarket mounted on my bike a Honda CR 250 if this helps.

Thanks in advance!

rob_fed3 months ago

Everything the other individuals posted is true of series wound starter motors. High current draw and heat will be your enemy to make a non-continuous duty motor work in continuous duty mode. That being said, I have a homemade go-kart that I made in 2001. It is powered by a Honda 1.3 kw starter motor. I use a Optima brand Red Top battery size group 22. It will last about 1/2 hour to 45 minutes of continuous use, the motor is on and off during this time to speed up and slow down. In the link, my kid's wanted a to drift, the rear wheels have large PVC rings around the tires to reduce the traction.

Without the rings, the go kart will have a top speed of about 25 mph.

If you attempt to use the motorcycle starter motor, I would ensure you disassemble the motor and hopefully it will have bearings at each end and not bushing, if it has bushings you will need to re-grease the bearing surfaces. But I would pass on this motor and find one with real bearings.

Bench test the motor in vise to ensure it runs freely.

Then make heat sinks to attach to the motor case.

A fan would help too, but must be sized correctly to be of any value.

Use large gauge power wire, I use 0awg made for car stereos, for your motor 2 gauge battery cable will work, but the larger the diameter the better.

dsirotic (author)  rob_fed3 months ago

Its great to hear this from someone that actually built this. I will see what I can do tomorrow! Thanks!

iceng1 year ago
It's probably a series DC machine designed to survive running a battery down once
or twice a year.
You should get four blocks trajectory out of a battery with it and be ready to fry an egg on the motor frame shell.
How many commutator bars does it have ?

dsirotic (author)  iceng1 year ago
Can you explain what you said like a noob? I am not good at electronics.
iceng dsirotic1 year ago
A starter motor is ;
  • Used infrequently
  • Made as small as possible
  • Has no provision for cooling
  • Expected to cool down by radiation and convection to ambient air.
  • Designed to survive running continuously until the supplied battery runs down ie battery gives away all charge current and can't turn starter another revolution very very rarely.
  • A very hot motor after sucking the battery, so hot you can fry eggs on it.
  • A series motor ie the armature is wired in series with the field windings
  • A motor whose torque increases as it is loaded and speed comes down and current and heating goes up.
  • The number of commutator copper bars that the brushes pass current to the armature decides how effective the machine could be at propulsion.
  • A machine that draws heavy current draining a battery and getting so hot that you might make a vehicle that could travel 4 blocks before the motor burned-up or the battery drained empty.

A

Starter motors are not designed for prolonged running. If you try to run it like a regular motor you will burn it out rather quickly.
dsirotic (author)  mpilchfamily1 year ago
I have seen a guy saying he built a go-kart with a starter motor, and it lasted for years. I would change the grease to oil, and maybe do some holes on the brushes for better cooling.
iceng dsirotic1 year ago
Ran the cart at half voltage or lied
Its not well suited to the job. Starter motors provide huge amounts of torque, but not for very long.