loving dad build - need some direction and input

[timdw5s]

Hi there! When I was little I visited my grandpa near Houston and remember seeing a kid with a go kart. Ever since then if I had boys I wanted to give them the opportunity to have that fun. Fast forward many years and I have 2 boys. I have this (pictured) pedal car that was given to us and wondering how hard it would be to go kart enable it. It doesn't have to be fancy or super fast (to start at least!). Could I just hook a motor into the existing sprocket? thanks in advance!

 

[Denny]

Well dad, an engine would ball that frame up in no time. We could talk you through building a Gokart from scratch if you have a cheep mig welder. We can even help you with learning to weld.

 

[Rat]

The most you could get away with is an electric kit... anything else and like Denny said it's going to fold that frame up.

I wouldn't even trust an electric over 300w

 

[timdw5s]

shoot... well, it was worth a shot. Any from scratch tips are appreciated. I do have access to a welder I could use.

 

[Rat]

shoot... well, it was worth a shot. Any from scratch tips are appreciated. I do have access to a welder I could use.

Keep it flat, square, and plumb. Having a perfectly leveled build surface is pretty crucial when building something from absolutely nothing scratch.

Common live axle width is 36" so keeping the frame close to that (30-34) is better for the axle ends and bearings, but you can taper in or out in the middle/seat area if you want/need.

I do recommend building it as a 2 seater for adult supervision, educational, and just general safety concerns while they learn the ropes... but not something so bulky that it is cumbersome and hard for them to control.

A one wheel peel (open wheel kart) is probably cheaper to build and easier to set up, but personally I find they have too many more limitations than a live axle... which has the primary issue of tearing up a yard/tearing up tires if ridden on pavement but are overall better and more fun IMHO.

Band brakes are better at stopping than they seem, but anything but Flintstones is better than tire scalpers

Building the base platform in square stock is much easier than fussing with trying to miter all the angles on the ends of round stock. Boring holes with a large bit to fit you're round stock bracing into helps quite a lot with rigidity over a just a basic butt weld. The other advantages being the ends dont have to be fussed with and matched as precisely because you can fudge mismatched lengths easier.

Even if you don't do a taper you're going to want something structural for horizontal and latteral bracing to reduce, dynamic flex, twisting, which consequently will control issues and permanent frame damages. Something like a low roll bar hoop and and angled outward side rails from close to the seat.

Pipe Insulation foam works great to pad bars to prevent bashed up elbows, knees and foreheads.

That's about all I've got other than maybe use a universal motor mount plate (49cc/79cc use a different pattern then 196/212, which is different than a Briggs 5hp flathead) So you aren't forced to use a certain size engine with the governor cranked.

 

[G.W]

I have seen a 2 stroke bicycle engine rigged to one. .aybe that's something to look into

 

[Rat]

I have seen a 2 stroke bicycle engine rigged to one. .aybe that's something to look into

Those are not reliable or powerful enough to warrant the expense nor the upgrades to squeeze them for Mo'power.

Don't get me wrong, I've played with them and know first hand that they are fully capable of being made to 60mph down the road... they just don't last long and the life is even shorter when made to rev that high

 

[G.W]

Those are not reliable or powerful enough to warrant the expense nor the upgrades to squeeze them for Mo'power.

Don't get me wrong, I've played with them and know first hand that they are fully capable of being made to 60mph down the road... they just don't last long and the life is even shorter when made to rev that high

I've coaxed over 1000 reliable miles off mine and it's still running good. I've got another I'm building now. It only takes some love and care.

 

[Rat]

I've coaxed over 1000 reliable miles off mine and it's still running good. I've got another I'm building now. It only takes some love and care.

If you don't mine anemic garbage and limitations Sure... you do you. I find them not worth the expense or effort

 

[G.W]

If you don't mine anemic garbage and limitations Sure... you do you. I find them not worth the expense or effort

I do admit they are lacking in lower end power, but OP stated it didn't have to be fast. It's all ideas.

 

[Rat]

I do admit they are lacking in lower end power, but OP stated it didn't have to be fast. It's all ideas.

For "Not fast" Bottom end grunt aka torque is EXACTLY what you need and you just answered yourself as to precisely why that's a logical suggestion on the surface, but is overall just not a very good idea.

Plus unless you pay a rediculous amount more for a less reliable variant like a BT80 or other electric start version, there's the manual clutch and pedal start requirement they all have... idk how young the OP's boys are but I do know those engines are stall happy and need to be pedaled up to a good speed (5-10mph based on weight)

That pedal kart does not appear to have any type of freewheel which means the pedals would need to be removed lest they get their shins and legs beat to a mangled pulp by tying into the exsisting powertrain. There are FFW (front freewheel) that could be installed, which the addition if a freewheel cog on one end or the other is mod that in my mind should be done regardless. Whether that thing gets a motor of ANY kind or not feels irrelevant from a safety perspective.

 

[panchothedog]

timdw5, you asked a simple question and now it seems everyone wants to argue about different engines. Not productive guys. You might get by with a 3 hp
79cc predator engine. The problem is you need a tiny engine sprocket and a large axle sprocket. I doubt very much that you will find anything that will work with your axle or a clutch compatible with the bicycle chain that is on there. It's a pedal car toy. Even if you got it to work, you would be breaking different parts one after another. Building a kart from scratch sounds fun and easy. Go look at some of the parts list for the kits sold at Go Power Sports, or BMI go karts. The list is long and extensive. Then add up.the cost. Pretty darn pricey if you are buying everything new. Don't know what your budget is or how old you kids are, but you will be DOLLARS ahead buying a 2nd hand kart. Weather buying a really nice one ready to go, or getting a beater cheap and fixing it up. It will less than building one. Word of caution. If you buy a used one, DON'T get one with a GY6 style engine. It will have electric start, forward and reverse and a list of almost unsolvable problems. Get an older American built kart with a industrial style pull start engine and forward gear only. Easy to work on, easy to fix, treat it with even a little bit of care and it will last for many years.

 

[Rat]

now it seems everyone wants to argue about different engines. Not productive guys.

Wasn't an argument, or even a debate. It was a dumbass suggestion being ripped to ribbons for every reason it was mechanically incompetent and won't work.

I'm all for proving that something that "can't be done" can, but even I am intelligent enough to draw the line at logic, and in this particular situation safety.

There is no mechanically SAFE way to do what was asked, that much I agreed upon from the get go.
IN THEORY, an electric motor set up could be made to work, however it would still require some modifications to exsisting hardware and platform. It's not logical or cost effective regardless of budget, and then there's still the high probability of a less than impressive end result.



Of course I suppose you must think I'm "arguing" still and I just don't have the bandwidth for petty bi★ch bullshit today.