Motorized Mobility Scooter.

Discussion in 'Performance Mods' started by ByronRACE, Feb 17, 2008.

  1. ByronRACE

    ByronRACE New Member

    I'm going to build a motorized mobility scooter.

    I'd like to be able to drag-start the engine using the scooters electric motor as the propulsion source.

    The scooter motor spins at approximately 4000rpm and has a shaft protruding from the motor that can be hooked to a sprocket for linking to the gas motor.

    I could take one of the clutch 2-stroke kits and make this work pretty easily. I'm not sure what sprocket ratio I'd need, but it wouldn't require much of a ratio; maybe 1:2 or what RPM do these 2 stroke motors run? Can someone tell me?

    Does anyone make a bump-startable 4-stroke kit? What if I were to defeat the centrifugal clutch and freewheel on the 4-stroke kit, couldn't I drag-start it then, and simply use the disengager to disengage the engine and shut it down? The mobility scooter has a 1.5hp motor. You'd stop, engage the disengager, start scooting on electric power, drag-start the motor, then back off the electric power and throttle-up. I just don't know if it would work to drag-start the 4-stroke kits like the Dax 50cc kit through the gearbox like that.


    As discussed in my "hello world" thread, I've built gas powered battery chargers for the scooter in the past. They are very inefficient, bulky, and heavy, but still useful when we go camping. I will be able to use the DC motor on the scooter as a generator with this approach (if I want to), and will also be able to use the gasoline power more efficiently as direct propulsion, and expect better economy, less weight, and a smaller package.

  2. cooltoy

    cooltoy Member

    Sorry we kind of highjacked your hello thread but that was an interesting "hello" and I guess we got carried away. I see you started another thread but now your getting away from the topic I'm most interested in. In the morning I will start a thraed of my own but only if you promise to join.
    As for your post above , the only thing that I'm not sure of is how your father will like it when that clutchless motor stalls out and he gets shot forward. I have a bit of a hard time following your plans but that kind of jumped out at me as I read it .
    Any thoughts?
  3. Papasaun

    Papasaun Guest

    Just a thought,,,,,
    Will this scooter be used to travel to shopping and such? It might not be welcomed in a store with a gas motor on it?

  4. Some of those 49cc chinese motors
    don't rev very high, and have electric start. They work fine,
    Steel cylinder sleeve, lots of clutch.

    I think that would be
    much easier for your Father to press a button and have the motor start
    than to rely on the batteries to bump start him all the time.

    You could find any Xtreme scooter on Craigslist and just take the motor off of one of those as well, they go for $50 used....
  5. ByronRACE

    ByronRACE New Member

    I'm not sure what topic you're referring to, but link to the thread and if I can provide any input or glean anything from it, i'll be there.

    Hmmm, I don't think the stalled motor would have that effect due to the 17:1 gear reduction of the transaxle. If the motor siezed, yes. But with a 350lb mobility scooter on the other end of that gearbox, and a 17:1 reduction box, I think the inertia of the scooter would drag along a stalled motor without much of a lurch actually.

    Maybe I'm wrong, wouldn't be the first time.
  6. ByronRACE

    ByronRACE New Member

    In a store, probably not...unless it was shrouded in a battery box and you simply didn't tell them. However, that's not the purpose. The purpose is trips across town to the flea market without fear of losing battery power. With a gas motor, he can use the engine on the way there and on the way back, and use quiet electric power while he's there. He has done this before dragging the generator set behind in a wagon, but that's not exactly efficient...and he'd use nearly a gallon of gas in a 6mi round-trip. The energy conversion losses are quite high. It takes near 2hp to make 20A at 24V with a BMW alternator... 1500 watts in, 450 watts out. Not too sweet. The 2.5hp chinese generator set I converted to 24V is more efficient, but weighs about 50lbs all by itself. And, both of the generator sets are pull-start, which my dad has a **** of a time doing. He's an old man.
  7. ByronRACE

    ByronRACE New Member


    I'm all ears!

    Are you talking about these motors?

    That looks like the cats meyow. Looks like centrifugal clutch, electric 12V start, and gear reduction transmission. No details though. Is there an english speaking person with detailed information about this motor? I have many questions.

    -Does it require a remote fuel tank?
    -2 stroke or 4?
    -comes with muffler?
    -clutch linkage details?
    -sprocket choices?
    -Can I seriously expect one to run reliably over and over pushing a heavy load? We're talking an hour or so continuous without exaggeration, and 10deg incline grades in spots.
    -does it have a battery charger to top up the battery?