Go Karting

[KiZ]

Oh no - we are getting to the conclusion tha Zack is gonna need a differential! Have fun making on of those yourself! Lol!

[Zack]

Thanks for the advice, guys.
Dark, without a differential it would still work, right? Because I have absolutely no experience or knowledge of them.

Here are my plans so far:

Have a lawnmower engine mounted so it's vertical. Attach some sort of clutch on it so I can stay still without turning the engine off. Kinda like a neutral-gear.
Onto the other end of the clutch put a gear, and then another one (horizontal) that is attached to the shaft that spins the wheel. I'll make this the back-right wheel.
On the other side of the frame, at the back, opposite the engine, I'd have a bunch of weights to counterbalance the energy emitted by the engine, so the cart doesn't go around in screeching circles.
I'd just attach a thick and strong sheet of plywood and screw a makeshift seat onto it. There I'd put a lever that's connected to the clutch, so from the cockpit I can shift into neutral.
Handlbars as well, directly over the front two wheels, to steer. Brake controls attached to them, bicycle-style, with their cables leading down to the front two wheels. Naturally, I'd shift into neutral before I use them so I don't risk having my front two wheels skidding.
Should I attach brakes to all of the wheels? Or are just the front two fine?
I could attach an additional 5 gears or so between the two gears I already put, which, when used, could effectively act as a speed control (since lawnmowers don't have that - they just have automatic mechanical and air-vane governors, I think).
How does this sound?

[Z!re]

Sounds good, we wants pictures of you riding it =)

[wizardlife]

Thanks for the advice, guys.
Dark, without a differential it would still work, right? Because I have absolutely no experience or knowledge of them.

Even a LEGO car doesn't turn properly without one.

I don't know junkers in the T.O. area, but I'd look around and see if you can find a junked Chevy Sprint or some other ultra-compact that you can rip parts like this off of.

Have a lawnmower engine mounted so it's vertical.

Make sure this works before you do it. Some have parts (fuel pan, I think) that only work in the upright orientation. I might go with an outboard motor instead for this reason.

I'd just attach a thick and strong sheet of plywood and screw a makeshift seat onto it.

I wouldn't depend on a sheet of 'strong plywood' for you body. I'd screw a frame together out of 2x4s and then make the floor out of 1/4" plywood.

Should I attach brakes to all of the wheels? Or are just the front two fine?

Do you have in mind like caliper brakes? Because if so, you'll need to actually use bicycle wheels on the front... and figure out how to mount the things.

I could attach an additional 5 gears or so between the two gears I already put, which, when used, could effectively act as a speed control (since lawnmowers don't have that - they just have automatic mechanical and air-vane governors, I think).

Sounds complicated. I'd stick to single speed first. After all, a gasolene engine's speed varies a lot with the fuel in the mix.

[Rhiannon]

I would recommend brakes on all four wheels, a go kart's not very heavy, and i'm sure you dont want to land on your head. And while you beta test, you should wear a helmet. i'm sure you want to live to see your 14th bday

[Zack]

Thanks for the advice, guys.
Dark, without a differential it would still work, right? Because I have absolutely no experience or knowledge of them.

Even a LEGO car doesn't turn properly without one.

OK, it's about time I ask this - what the hell is a differential, anyway?

Have a lawnmower engine mounted so it's vertical.

Make sure this works before you do it. Some have parts (fuel pan, I think) that only work in the upright orientation. I might go with an outboard motor instead for this reason.

When I said "vertical", it means upright in the normal position it would be for mowing. You're right in saying it won't work on it's side, though, because I'm pretty sure that lawnmower carburetors use the float-bowl method of carburetion.
Also, using an outboard motor is definitely unadvisable because except for the tiny ones of .5 or 1 horse power, they are water-cooled which means I would need a large water reservoir. Also, they usually use external gas tanks and so I'd need space for that.
Another thing, I have a gas mower available, but not an outboard. And outboards, even when purchased used, are expensive.

I'd just attach a thick and strong sheet of plywood and screw a makeshift seat onto it.

I wouldn't depend on a sheet of 'strong plywood' for you body. I'd screw a frame together out of 2x4s and then make the floor out of 1/4" plywood.

I know nothing about carpentry...so thanks for saving me the humiliation of climbing into a Go-Kart and having it collapse.

Should I attach brakes to all of the wheels? Or are just the front two fine?

Do you have in mind like caliper brakes? Because if so, you'll need to actually use bicycle wheels on the front... and figure out how to mount the things.

Ah, crap, I thought I might have a problem there. Well, I'll have to think it out. Anyone have a run-through for me on different types of braking methods?

I could attach an additional 5 gears or so between the two gears I already put, which, when used, could effectively act as a speed control (since lawnmowers don't have that - they just have automatic mechanical and air-vane governors, I think).

Sounds complicated. I'd stick to single speed first. After all, a gasolene engine's speed varies a lot with the fuel in the mix.

I've just learned that lawnmowers *do* have speed control sliders, kinda like outboard engines do. A slider bar from STOP to START to FAST. So no worries there.

I've build a mini-model out of lego (with an electric motor). Problem is, no matter how much I counter-weight it, it still tends to go around in circles. I'm not to sharp at physical principles, so I need help there at understanding what the problem is and what I can do.

Rhia: 'course I'll use a helmet...I'm not stupid. I'm also going to install a seat belt.

[Z!re]

A differential stops the driving wheels (the rear ones) from going at different speeds...



I just built one in Lego too, it runs straigt... but then again.. I placed it along the lenght of the cart...

o o
----
o o

Where --- = Egnine, and o = A wheel (Horray for crappy ASCII pictures )

And then used some cogwheels (How do you spell that?)



Not sure that can be done with your go-cart...



Anoth thing you can do is:

o| o
o| o

( | = Engine, o = Wheels, driving direction = left)

And have the rear wheels locked togheter, and a, uhm (gah, forgot the english word), a band, sort of, that connects the engine, with the rear wheel axel...


That should stop the wheels from going at different speeds, but the cart needds to be balanced...

Balanced cart, and locked wheel axis should do it.... And it's easier to balance the real thing than a lego thing...




Braking, if you're sitting far enough back, then you could brake using rear wheel...

Have it so that when you pull a lever, or stomp a plate.. a block of wood/Metal (preferably) goes down and huggs the wheel...

_

|
|----
|


Where:
|
|---- = Wheel
|


_ = A piece of metal...


And when braking:

_
|
|----
|


Should work, and because the wheels are locked toheter, you only need it on one side, which makes it easier...


Front wheel braking is hard, as they need to turn (duh) and generally are less stable then the rear ones...

[KiZ]

Thanks for the advice, guys.
Dark, without a differential it would still work, right? Because I have absolutely no experience or knowledge of them.

Even a LEGO car doesn't turn properly without one.

OK, it's about time I ask this - what the hell is a differential, anyway?

It will work without one, but one of the rear wheels will skid.


here is a more simple explanation of a diff:

When you are going around a corner, notice that on one side of the car the wheels turn faster than the other side. If the wheels are directly connected, then this will cause problems, because the wheels want to turn at different speeds, but they cant (being directly connected). A differential allows the engine to power BOTH rear wheels, but allows them to turn at different speeds.

Here is a simplified differential

The two drive shafts go to the wheels, and the entire device is turned like a gear by the engine.

[eno_on]

The gearbox would be a mess to build...a little misalignment could grind the gears. I'd have just one speed - foreward, and only two gears (one crown on the engine and a differential for the wheels. You also probably want pillow block ball bearings to keep the drive shaft turning smooth.
pillow block:
__
|o|

[wizardlife]

Here is a simplified differential

The two drive shafts go to the wheels, and the entire device is turned like a gear by the engine.

dp has it.

This is why I'd say to find a junker where you get something like this ready-to-go... there's no way you could build it without a machine shop.