Schwinn scooter gas conversion

[J.S.@SMS]

Please let me know if I should get this moved to the minibike area.

I know I'm gonna catch some heat about this, but I'm planning on converting an electric Schwinn scooter I got for free (green), to a gas powered scooter, using a 49cc two stroke that I was given for free (not green). I've found a new clutch drum that has a 25h sprocket and chain that I'll put on the engine instead of the current t8f? sprocket clutch, which will allow me to use the original wheel sprocket (I'll check the original first). The gas tank will be mounted on the seat post, and I'll be adding on a regular cable throttle. All the electric wiring will get ditched. The battery compartment will become an under floor storage area. When I'm done it should do 20-25mph instead of the boring 12mph that it did stock. The reason I'm doing this is that I can fix up the engine for 30 or 40 bucks and make an adapter at home to mount the engine. It'd cost that just to get the batteries, let alone the battery harness and charger, and then I'm running the risk of something else being bad, like the motor (I have no clue about the history of this thing, but I think there was a reason it was free).

The scooter to be modified:


The model (for reference):


The 90t sprocket:


And does performance mean something else in the electric community? Because last I checked .67hp and 2600rpm isn't that good. Of course I'm swapping in an engine with only 2-3 hp, and that electric engines have more torque.

 

[landuse]

I'm looking forward to this one!

 

[J.S.@SMS]

I checked yesterday, it looks like the current clutch sprocket is close, but i won't be sure until disassembly. The motor is mounted to a plate that seems pretty strong, So I'll probably mount the engine to that. I'm not sure if I'm going to mount the engine to that plate, with the clutch bolts, or make a mount that the engine sits on, that attaches to the plate. I just realized that I haven't described the engine. It's one of these that I got from my uncle for free.
https://www.ebay.com/itm/254435302857
And in case the listing disappears.

It needs a new top end and coil ($26 on amazon), and a carb clean.

It came on this pocket bike. Which he also gave me.

 

[JTSpeedDemon]

What top end??? That term only really applies to 4 strokes. Do you mean the cylinder? Cylinder head?

 

[J.S.@SMS]

What top end??? That term only really applies to 4 strokes. Do you mean the cylinder? Cylinder head?

From Snowgoer.com <takes you to the page
"Rebuilding a two-stroke engine’s top end includes servicing the cylinders, pistons, rings and related gaskets and O-rings. The top end of a two-stroke engine might need to be rebuilt if there’s been a reduction in compression that can cause hard starting when the engine is warm, inability to idle or a loss in power."

It needs a new cylinder, piston, wristpin (comes with piston), rings, and gaskets.

 

[JTSpeedDemon]

Ooohhh, I was thinking of the valvetrain and stuff in a 4 stroke. That's my understanding of the term "top end". I guess I was mistaken!

 

[J.S.@SMS]

My understanding is that in two strokes, top end applies to the head and cylinder (sometimes one piece, like mine), piston and rings. And in four strokes, it applies to the head (including valvetrain). Though on some four strokes, the head and cylinder are one piece (Like my GC160).

 

[itsid]

25mph on a kickscooter with a short trail (essentially caster) and a long throw
(high center of gravity long handle bar) and relatively small wheels..

Be careful,
that sounds like you're in for serious death wobble and a not too gentle face plant :
So when you give it a try, maybe a helmet isn't too bad of an idea

personally I think you'd be best reusing the t8f and the rear sprocket from that pocket bike!
that way you keep it close to the ratio the bike had (meant for the engine)
and don't have to worry too much about if the elecric setup was in fact higher geared since the motor likely has a bit more torque than that engine..
(and you wouldn't destroy the clutch if bad comes to worse)

'sid

 

[J.S.@SMS]

I am thinking about adding some more caster when I get my welder going, since it does seem a bit unstable (could be the flat tires, it needs new tubes). And the wheels are actually around 12-13" tall, which surprised me. I may shorten the seat post a little, that should help lower the center of gravity. Also, I could fill the battery box with bricks, that should lower the center of gravity as well. And I'm definitely going to wear a helmet, knee and elbow pads, and a bubble wrap suit. I have enough trouble with bicycles at 20mpm.

And I think I'm better off with using the 90t sprocket that's on the scooter, since it would give me about 21mph at 7000rpm (which this engine should hopefully do). The stock pocket bike sprocket was a 68t, that would give me 28mph at 7000rpm. And the electric setup was geared numerically lower, since the motor sprocket was an 11 tooth and the tire sprocket was a 90t (8.2:1 ish). The pocket bike had a 7t sprocket driving a 68t (9.7:1 ish). Using the 7t sprocket (they have them in both t8f and #25) and the stock 90t, I'd get about 12.8:1, which I'm more comfortable with.

 

[J.S.@SMS]

The parts came in over the weekend, and they’re already on the engine. And think I found a name for this thing, Freeby Jeebies, because I’m sure this this thing’ll be “fun” to ride, and because the scooter and engine were both free. So far the only money I’ve thrown at this thing is 14.75 ish for a throttle (grips cables and kill switch), 25.32 for a top end kit (with the gaskets and a coil), and 6.99 for a carburetor.

Now for the chain, the bike and the scooter have the same chain, so the scooter chain will work (I checked the chain against both sprockets). So I’m good in that department.

The engines first fire will hopefully be tomorrow if all goes well. The kill switch is, by some miracle, wired correctly, I hope. I guess the Chinese don’t use wiring diagrams. But I’ll know tomorrow.

I’ll put up some pics tomorrow when I’m at my computer.

 

[Jbrewer like]

If you're using those wheels , inspect them before every ride. I've had the same type come apart violently.

 

[J.S.@SMS]

Which ones, the wheels on the scooter or the wheels on the bike?

 

[Jbrewer like]

The Schwinn scooter wheels.