Go Kart Construction Help

[GEESMAN]

Dear Users,

 

I have always wanted either a go kart or to repurpose a tractor or lawnmower into a little drift demon, but I am worried about so many things about kart/vehicle construction. Here are some topics that if you know stuff about lets discuss!

I want to build two vehicles currently, one slow and one fast.

 

A) If I go for a gas engine, how much horsepower would I need to go slow? And how much to go fast? Say my craft is 250 pounds including my weight, would a 7 hp engine be nice, or what equations can I use to calculate this.

 

B) If I go for a electric motor and some fat batteries what equations are there to calculate how many Watts I would need to go fast or slow, any info on this would be great.

 

C) If I want to rebuild or build my own front of the car, how do I build an axle and connect body work onto it? Any ideas?

 

D) How do I know if my chassis can stand the forces I will be placing on it? Should I make everything out of iron or steel? Do I need like a roll cage for stability? I was gonna build the body work with wood. I really dont need to have my vehicle break at speed.

 

E) How do I connect a steering wheel to an axle or do they come as a combo? Any videos or links would be awesome.

 

I know this all may sound vague and like I dont know what I am doing and haven't done a lot of research, but I have, most go kart builds start with a pre built go kart or something thats expensive, I want to build something so custom that I want to DYI it all with literally 0 knowledge beforehand. Absolute learning time.

 

Thanks!

 

-GEESMAN

[IkeaGnome]

2 minutes ago, GEESMAN said:

Dear Users,

 

I have always wanted either a go kart or to repurpose a tractor or lawnmower into a little drift demon, but I am worried about so many things about kart/vehicle construction. Here are some topics that if you know stuff about lets discuss!

I want to build two vehicles currently, one slow and one fast.

 

A) If I go for a gas engine, how much horsepower would I need to go slow? And how much to go fast? Say my craft is 250 pounds including my weight, would a 7 hp engine be nice, or what equations can I use to calculate this.

 

B) If I go for a electric motor and some fat batteries what equations are there to calculate how many Watts I would need to go fast or slow, any info on this would be great.

 

C) If I want to rebuild or build my own front of the car, how do I build an axle and connect body work onto it? Any ideas?

 

D) How do I know if my chassis can stand the forces I will be placing on it? Should I make everything out of iron or steel? Do I need like a roll cage for stability? I was gonna build the body work with wood. I really dont need to have my vehicle break at speed.

 

E) How do I connect a steering wheel to an axle or do they come as a combo? Any videos or links would be awesome.

 

I know this all may sound vague and like I dont know what I am doing and haven't done a lot of research, but I have, most go kart builds start with a pre built go kart or something thats expensive, I want to build something so custom that I want to DYI it all with literally 0 knowledge beforehand. Absolute learning time.

 

Thanks!

 

-GEESMAN

A) Small. I'm building one this winter with a Yamaha 110. Should do 40 or 50mph depending on sprockets. You can always resprocket to go slower. 

B)I have no clue.

C)There is a YT channel that does this stuff a lot, including parts lists. 

D) Mine will be steel DOM, I'm also planning on running it down the drag strip once next summer

E) Steering shaft to pitman arm to steering.

[Crossbred]

B) 1HP = 746W. 

So much of this depends on the size and quality of the build. Are you down for real welding or are you going to go with bolts? Is this barely going to fit one person or will this seat a pair comfortably? If it's smaller I'd use as much aluminum as possible without creating problems because of the cost effectiveness and low weight. Your axles definitely don't need to be SUV grade but don't cheap out to avoid warping them over time. Steel might be better here. Send chassis design ideas and I can better recommend materials. 

 

As far as max speed goes you can always change that through gears or messing with voltages. What a more powerful motor does is enable higher acceleration to the speed you want. 

[Orange1]

Harbor freight predator engine 250cc is nice, 4 stroke.

Electric is more work, but I'd go with a 10kw motor with a Kelly controller and depending on your speed probably 48 or 52V, maybe even 72V but dont do lead acid batteries just buy used car lithium batteries.

[MadAnt250]

16 minutes ago, Orange1 said:

Harbor freight predator engine 250cc is nice

For a short time. Well... maybe it depend on use case.

 

On 11/6/2020 at 6:51 PM, GEESMAN said:

I want to build something so custom that I want to DYI it all with literally 0 knowledge beforehand. Absolute learning time.

For education purpose, I suggest starting off with an old lawn tractor (with no blades for safety). They are simple, cheap and can be easily modified to go faster than the stock speed.

[IkeaGnome]

If you don't know how or aren't comfortable welding you're far better off doing what @MadAnt250suggested. Even with a lawn tractor depending on your engine there will still be some welding. I'm getting ready to build 4 this winter for some friends and I to rip around. One will start with a Yamaha TTR110 engine with a big bore kit to 125CC. It'll get a turbo once I find a good deal on one. The other three are chainsaws that I've accumulated for dirt cheap. 2 are converted over to run a combination of 2 stroke and methanol injection. All will have TIGd chromoly frames. As far as actual bearings for axles, these are very expensive, but what I'm going with for the rear axles on all 4.

https://www.motionindustries.com/products/brands/Dodge

[kelvinhall05]

I wouldn't do electric, it might be more fun than a small gas engine but it'll be a lot more expensive, a lot heavier, and potentially more dangerous depending on what kind of batteries you'd use.

[Orange1]

15 hours ago, MadAnt250 said:

For a short time. Well... maybe it depend on use case.

Predator engines are Honda clones and they are cheap. You dont want cheap then buy oem Honda engine.

 

Electric would be fun but the battery would be the most expensive part as is always the case for anything electric. I saw a 26,000 watt motor that would kick ass but that kinda of power requires really expensive controllers. Thousands of dollars vs a couple hundred bucks from Harbor Freight.

 

If I were you, I'd start looking for used go carts and frames to buy and modify, or find a store that sells what you are looking for. Even HF has cottage carts for sale, then there are ex go cart racers. The lawn mower thing is more of a southern usa thing. Buy a cheap used Lincoln buzz box welder, find some cheap steel and get at it.