Budget build-off kart for work

[anickode]

Howdy all! Just wanted to share my latest project... A bunch of us at work decided it would be fun to all build cheap yard karts and have an "employee grand Prix" at the end of summer. Got permission to race on the property and everything.

The rules for the race, in the interest of leveling the playing field a bit, require you to build the kart yourself, and limit the build budget to $400, but if you can score freebie parts, their value doesn't count against you. Beyond that, these are the requirements:

Stock engines 220 cc or less. 4 stroke industrial style engines only.
Stock carbs, jetting allowed
Intake and exhaust allowed
Governor adjustment allowed
Governor removal prohibited
Centrifugal clutches only
Must have functional brakes
Must be of quality (ie, safe) workmanship

My kart has an extra design stipulation... It has to fit in the back of my crew cab Colorado, which has a topper with barn doors, so the maximum overall dimensions can't exceed 60" long and 42" wide.

I started on it at 5:30 pm. It's now 10:30 as I'm typing this. Built entirely flying by the seat of my pants, with only a mental blueprint to go by.

I used almost exactly one 24' stick of 1" square tube ( literally 4 inches left over), a scrap of 1.5" square for the front axle with some slice-n-diced 4" square tube for the spindle brackets, a scrap of 1.5" .065 wall dom tube for the steering column, and a scrap of 1.5" angle for the engine mount. Total cost so far is around 40 bucks. It's sort of hard to keep track of price exactly, since I keep a lot of steel in stock, but I'm well on track to come in under budget, especially since I will make most of the parts from scratch, save for the rear axle, clutch, sprocket, and wheels.

I've got an almost new Briggs 190 intek off a broken pressure washer (wasn't drained, froze, cracked the pump) that I got for free a while back that will go on it.

 

[anickode]

You can just make out the wheel of the rat wagon, the engine that's destined for this kart, and my "mock-up" seat that I use. It's just a cheap metal commercial chair with the legs cut off, but it's basically perfectly proportioned for a go kart seat, so I'll sit it on the floor and sort of design everything else around me to get a feel for stuff like steering and pedal position and whatnot.

---------- Post added at 11:14 PM ---------- Previous post was at 10:59 PM ----------

And here's a quick tip... For a slop-free, smooth acting steering column, a piece of 1¼" .065 wall DOM tubing is almost a perfect fit for some 1/2"x1⅛" El cheapo radial bearings, just by reaming it out a tiny bit (and I mean tiny) with a die grinder.

 

[anickode]

Next question is... Do I go cheap and get a 3/4" axle, since I already have some 3/4" pillow blocks laying around, or go all out for the standard 1" axle...

 

[MTNSleder]

1 inch.. that way it's not completely useless after the grand prix...

 

[Goat]

Howdy all! Just wanted to share my latest project... A bunch of us at work decided it would be fun to all build cheap yard karts and have an "employee grand Prix" at the end of summer. Got permission to race on the property and everything.

The rules for the race, in the interest of leveling the playing field a bit, require you to build the kart yourself, and limit the build budget to $400, but if you can score freebie parts, their value doesn't count against you. Beyond that, these are the requirements:

Stock engines 220 cc or less. 4 stroke industrial style engines only.
Stock carbs, jetting allowed
Intake and exhaust allowed
Governor adjustment allowed
Governor removal prohibited
Centrifugal clutches only
Must have functional brakes
Must be of quality (ie, safe) workmanship

My kart has an extra design stipulation... It has to fit in the back of my crew cab Colorado, which has a topper with barn doors, so the maximum overall dimensions can't exceed 60" long and 42" wide.

I started on it at 5:30 pm. It's now 10:30 as I'm typing this. Built entirely flying by the seat of my pants, with only a mental blueprint to go by.

I used almost exactly one 24' stick of 1" square tube ( literally 4 inches left over), a scrap of 1.5" square for the front axle with some slice-n-diced 4" square tube for the spindle brackets, a scrap of 1.5" .065 wall dom tube for the steering column, and a scrap of 1.5" angle for the engine mount. Total cost so far is around 40 bucks. It's sort of hard to keep track of price exactly, since I keep a lot of steel in stock, but I'm well on track to come in under budget, especially since I will make most of the parts from scratch, save for the rear axle, clutch, sprocket, and wheels.

I've got an almost new Briggs 190 intek off a broken pressure washer (wasn't drained, froze, cracked the pump) that I got for free a while back that will go on it.

That was a very productive 5 hours. Nice work.

 

[anickode]

Spent a bit of time on the steering tonight. Got the steering shaft made and installed in the column.

Steering wheel made from scratch from a piece of 1" OD by 1/4" wall tube, some 1"x1/4" flat bar, and some 1/2" EMT bent with a conduit bender. Gotta love those galvanized welds. I got most of the rough grinding done on the wheel, but I plan to smooth it all out and blend everything in to give it a nice clean look. I am also going to pound a steel ball into the open ends of the conduit and tack and grind to give it finished ends I used an interesting coupling method on the wheel; it's the 1/2" shaft in a 1/2" bore, with a hole drilled down through the joint and tapped for 1/4-20 threads. It acts as both a retaining bolt and a key. This allows me to weld the Pittman arm to the steering shaft, but still have the steering shaft be removable, without dealing with splines or keys and steering wheel hubs, etc. Quick, cheap, and very effective.

I robbed the tires off my hand truck to help me mock up the steering. They're just the thing for the job, since they're 13x5-6, which is what I plan on using on here anyway. Depending on how the kart wheels are offset, I may need to run a small spacer or a couple washers behind the wheels to buy a bit of clearence from the steering arms.

 

[Bbqjoe]

Nice.
I love the smell of welding galvanized.

 

[Goat]

Nice.
I love the smell of welding galvanized.

It cleans out your sinuses. I used to smell lots of it welding cable trays in the nukes.

 

[anickode]

It cleans out your sinuses. I used to smell lots of it welding cable trays in the nukes.

It's tough to get a decent weld on it without thorough cleaning... I was in a lazy mood tonight, so I just cranked the machine up and blew through the zinc, so the welds are pretty ugly. I'm sure the case of Founder's PC Pils I brought home today isn't helping my welds either.

 

[Goat]

It's tough to get a decent weld on it without thorough cleaning... I was in a lazy mood tonight, so I just cranked the machine up and blew through the zinc, so the welds are pretty ugly. I'm sure the case of Founder's PC Pils I brought home today isn't helping my welds either.

Just drink lots of milk and crank up that 6010. Keep the fan pointing away from you too.

 

[anickode]

Just drink lots of milk and crank up that 6010. Keep the fan pointing away from you too.

I've had metal fume fever before. It was unpleasant to say the least. I spent 2 straight days torch cutting a bunch of hot dipped frames to prep them for modifications. Working outside, with a breeze. It still caught up to me. No worries about a couple little zapadoodle welds on some EMT though.

 

[WeddingRing]

Well, there's a fuel tank coating used in military aircraft painting. It's PRC, and it'll mess you up with just a little bit of respirator leak.

 

[anickode]

Well, there's a fuel tank coating used in military aircraft painting. It's PRC, and it'll mess you up with just a little bit of respirator leak.

IMRON paint will screw you up too. It's used on most civilian aircraft and a lot of industrial applications. It's polyisocyanide based. My uncle had a friend that died at 45 years old. He ran his own shop painting small planes, and used a respirator instead of a fresh air hood like you're supposed to.

Zinc chromate is used on military planes as well... That's bad juju too.

 

[anickode]

Picked up a stick of 3/8" cold rolled and some 3/8" tie rod ends on the way home from work today. I love CarQuest... I live near one of their few remaining stores, and they always seem to have those odds and ends pieces that nobody else carries, and not real expensive either. They were only 4 bucks apiece.

 

[anickode]

I guess it's just not my night. Messed up my tie rods. I measured and cut them without factoring in the crossover at the Pittman arm to get some Ackerman out of my leading link steering setup. I'll probably redo them... It'll bug me if I don't, and of course I just bought a little 4 foot drop instead of a full length like I typically do, so there's not enough left over.

Steering works awesome though. I swapped out the steel washers on the kingpins for thrust bushings (basically oilite bronze washers), and greased the kingpins prior to reassembly. The tight tolerances on everything and the roller bearings on the steering shaft make for extremely tight yet smooth steering. Zero play anywhere.

 

[B_Bimmer]

Continue the wonderful pictures. I am really enjoying your thread, I love budget builds.

 

[anickode]

Progress has been slow the past 10 days or so... Camping trip, catching back up at work, getting ready for the kids to go back to school...

I did get my axle mounts started. I'm going to use 3 hole flangettes for bearing mounts. The mounts are made from a piece of the same 4x4x¼" square tube I used for the spindle brackets. I will add pics when they are done. I just have some carbide burr work to do on them.

Still working on a freewheel setup to run a 2 speed jackshaft. I have a couple promising leads that should be fairly inexpensive.

 

[anickode]

This is what i'll be using for axle mounts. Should be good and sturdy compared to some I've seen. They're cut from 4x4x¼" square tube. (The same 1 foot scrap my spindle brackets came from). Chopping up big square tube is a good way to make parts with bends you would otherwise need a press brake or have to cut and weld.

Parts were cut out simply using a cutoff wheel on a grinder (Metabo slicer wheels... Good stuff. I cut out both of them and didn't even go through a whole wheel) and the hole was made with a 2⅛" hole saw and then beveled with a carbide burr. It could just as easily be done with a cheaper grinding stone, or simply using a slightly larger hole saw and not bevelling.

Yes I have faster methods at my disposal but I'm sort of trying to demonstrate that this can be done with fairly simple stuff.

 

[anickode]

Oh yeah, and you can see in the background I made a seat. Just some 1/2" BCX plywood, some foam, and the rest of the harbor freight moving blanket I cut up to upholster the rat wagon seat. And Staples. Lots of Staples.

I actually quite like the cheap moving blankets for seat cloth. It's pretty durable, but just stretchy enough to make the corners easy. It's not waterproof, but its CHEAP and it works.

I may go with a softer foam in the long run though. This stuff is a closed cell material, so it doesn't sponge up water, but it's rather stiff and doesn't offer much padding for sitting on. It's similar to pool noodle foam.

---------- Post added at 11:26 PM ---------- Previous post was at 11:03 PM ----------

We also unanimously agreed to allow torque converters in the race now, since they're so cheap and nobody has their kart finished yet. I might abandon my 2 speed setup and just go with an eBay clone converter and a 6:1 ratio

 

[bob58o]

It's a race. Gear it faster. Make it more "drive-able" later

What does the Grand Prix course / track look like. Lots of tight turns? Long stretches?

Can probably corner at 20 mph if not faster, right?
13" Tires
30 Series TC
Peak Torque ~ 2300 RPM

Not really sure about this (easier with a Clutch) but it seems as though if you gear 5:1 (4.5:1 with overdrive) you can come out of turns staying closer to peak torque without slowing down as much. I don't really know how the TC shifts ratios as you let off the gas to slow down, then accelerate through the turn.

2300 RPM with 4.5:1 (5:1 x 0.9 (Overdrive)) and 13" tires (~12.6" in real life?) is about 19 mph. Unless it's a tiny track, seems you could turn at 19 mph. Does the overdrive gear ratio matter at 2300 RPM when coming out of a turn? I'm not exactly sure. I think it would be like down shifting at peak TQ so you can quickly Rev back up and into high gear after the turn.

But people gear fun karts with 13" tires 6:1 with CC's, so I'm pretty sure you could get away with 5:1 and a TC. Would give you ~40mph at 4800 RPM (Peak HP)

Sorry for the rambling. Especially since I'm not exactly sure what I'm talking about. This is an interesting topic for me.