Electric Stingray to 4-stroke Conversion

[KCvale]

Did you know there was an Electric Schwinn Stingray made back in '2005?
http://www.gizmag.com/go/4054/

Rear hub electric drive, and a fake plastic engine to hold the batteries and big fake exhaust pipes for the look.

It was all show and no go with ~300 watt SLA system.

Anyway, a local guy had one and wanted me to see if I could 'hop up the electrics' to make it faster.
It was 15mph kids toy, literally.

he didn't really want electric anyway because of his commuting needs so I suggest a 4-stroke.

What a PITA! But I pulled it off.

He wanted footpegs and has no desire to pedal so I used pedals to make fixed footpegs and all was good.

Now he wants it to at least look like it can be pedaled as he as worried abou the law...

The problem is it has no pedal sprocket, it wouldn't fit with engine mounted low which is what he wanted.

Any thoughts short of having to move the engine to make it look it has working pedals with a chain on it?

I can put the pedal arm with a sprocket on, but nowhere to run a chain.
I know, a darn silly request, but I figure why not ask.

 

[GoreWound]

this is funny, I am trying to do the same thing and am saving up cash to order parts from you to do it.
my plan involves the pedals not being a dummy set. tell me what you think: one of your long shaft transfer cases flipped over so the output is in front of the engine, a freewheel bottom bracket with ~30 teeth on it's sprockets, a tensioner to pass the chain below the motor, a Strumey-archer hub for gearing.

I am hoping that with the long output shaft you should be able to get the leeway on the chain side of the motor. It may be possible to have the motor output to a larger tooth-count gear on the bottom bracket as it may completely clear the engine once arranged that way, allowing for a small sprocket chained to the rear wheel. a smaller diameter sprocket there should help clear to motor.

your frames dimensions look a little different from mine (though I gather that is not uncommon for these bikes) and I would love to know how your engine is mounted, I'm over here shopping around for a welder to replace the bottom tube with some rectangular tubing so I can get my motor mounted!

also as far as faking the chain goes, a chainguard can hide many sins.

 

[KCvale]

this is funny, I am trying to do the same thing and am saving up cash to order parts from you to do it.
my plan involves the pedals not being a dummy set.

I have regretted doing that build since day one.
The customer has been a world class ignorant dick since day one. You may know the type, knows nothing about mechanics, and even against sound advice says 'do it this way' then complains when it has issues.

I actually profile my potential new customers for this now, and sometimes have to tell them in a softer way what I really feel, 'You are to Incompetent to Operate and Service a Motorized Bicycle.'

tell me what you think: one of your long shaft transfer cases flipped over so the output is in front of the engine, a freewheel bottom bracket with ~30 teeth on it's sprockets, a tensioner to pass the chain below the motor, a Strumey-archer hub for gearing.

That's how I convert a 4G to my 10G, put in the long shaft then drill new engine mounting holes in it.

You might not even need to drill new holes.
Its all about what else is in the way for the cross, in my case the oil filler in the back.

As far the 4G dry belt transfer case is concerned it doesn't matter.
I have re-drilled a regular 4G for a SBP shift kit to get to fit a Slugo

I am hoping that with the long output shaft you should be able to get the leeway on the chain side of the motor. It may be possible to have the motor output to a larger tooth-count gear on the bottom bracket as it may completely clear the engine once arranged that way, allowing for a small sprocket chained to the rear wheel. a smaller diameter sprocket there should help clear to motor.

your frames dimensions look a little different from mine (though I gather that is not uncommon for these bikes) and I would love to know how your engine is mounted, I'm over here shopping around for a welder to replace the bottom tube with some rectangular tubing so I can get my motor mounted!

also as far as faking the chain goes, a chainguard can hide many sins.

I just cut the electrics base mount parts away from the base it already had, and mounted a new flat base to fit that accommodated where I wanted the engine.

I have no idea why you want to modify a base to tubes but quite frankly I hate everything about that bike frame and vow to never work on one again so I may not be the best of help to you.

 

[GoreWound]

Ah, mine was not electric to start with so I got nothing in the way of mounting, hence my plan to swap the bottom frame tube with a square tube. Hopefully I can mount the engine directly to the frame then, no mounting plate or adapter at all.

Assuming everything fits together as well as I imagine it will, which it probably won't, your longer shaft transfer case should allow me to center the engine in the frame (not possible with a standard transfer case) and run a chain from the transfer case output directly to the bottom bracket. The location of the bottom bracket on this bike is why I'm planning on mounting the transfer case backwards (upside-down?)
Gearing is going to be fun, I'm sure...


As for your build here, lifting the engine may not be super difficult, and there's room for it (on mine there is less than a half inch of clearance above the motor). Failing that you can probably get or make a chain-guard that at least hides the obvious lack of a chain.