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aka Larry 10-11-2019 09:09 AM

New Cooler Kart Build
 
Hello everyone!

About 8 years ago I was at a local race track and saw a guy who built a "cooler kart" to get around the paddock. It was just a large ice cooler sitting on tube frame that the rider sits on. I thought it was neat as **** as it served two purposes, transportation, and keeping cold beverages! Ever since, I've wanted to build my own, but it seems that for whatever reason, one project or another has taken it's place. Now just might be the time to finally get it done.

Over a few weeks I've been collecting information on DIY builds, parts, etc from various websites, including this one. Thus far I've put together a parts list of about 95% of what I'd need just to get my head around the budget needed for the project.

Being a draftsman for over 30 years, I like to make a drawing for everything. I'm not much on just "figuring it out as I go". Right now I've got a preliminary design for the basic frame, but I'm missing several key dimensions to make it more final. If you guys can help with those and other items it will help me to finally move forward on this overdue project of mine.

Here's my current (very) basic plan. Stay tuned for a drawing later today. Please feel free to ask questions, offer suggestions, provide input, etc.

Frame:

- 1"x1" square tubing.
- Overall dimensions of the whole thing can't exceed 48"L x 37"W
- Cooler itself will be a Yeti 65

Wheels/Hubs:

- 4.10 x 3.5 (HF)
- Double-Flange Hub w/5/8" bearings for the drive wheel
- Single-Flange Hub w/5/8" bearings for the drive wheel

Engine/Driveline:

- Predator 6.5HP 212cc
- 60T #35 Sprocket
- 12T #35 Centrifugal Clutch

Speed Control/Brakes:

- Combination ATV thumb throttle/hand brake (handle bar mount)
- 4" Band brake

One design hold-up right now is how I want to do the steering. I'm leaning toward a T-handle bar design (vs. a wheel) so I can use an ATV thumb throttle and hand brake. The thing is that made for a 7/8" diameter tube, and I'm not sure where I'd source that size tubing. I'd like to use EMT conduit or something to keep it simple and light.

Another design issue I have is I don't know the actual dimension of the engine in relation to the drive wheel/sprocket, so I can't finalize the rear axle design. I plan to weld a pair of 5/8" bolts onto the end of a 1" square tube for the rear axle. Really I'm trying to avoid buying the engine/wheels/hubs etc up front before I finish the design. The one caveat is the engine is on sale this weekend for $97 and that's hard to pass up! I guess if I pull the trigger on that then I'm committed right?

So you know what I'm working with, I'm decent welder as I've built roll cages for four race cars as well as many other small projects. I also have a drill press, plasma cutter, Evolution chop saw, horizontal band saw, and most basic hand tools.

I'm open to any and all suggestions, information etc, so please fire away!

JTSpeedDemon 10-11-2019 09:17 AM

Do NOT use HF tires! They will disintegrate and are very dangerous. The hubs and bearings are also terrible.
Invest in some quality rims. I would get some steel split rims from www.ombwarehouse.com
Otherwise, can't wait to see it come together! :thumbsup:

aka Larry 10-11-2019 10:14 AM

Quote:

Originally Posted by JTSpeedDemon (Post 534476)
Do NOT use HF tires! They will disintegrate and are very dangerous. The hubs and bearings are also terrible.
Invest in some quality rims. I would get some steel split rims from www.ombwarehouse.com
Otherwise, can't wait to see it come together! :thumbsup:


Thanks for the info.

I was planning to use these hubs (which include H.S. bearings) but I don't see any wheels (on the site you linked) that use the 2-13/16" bolt circle.

JTSpeedDemon 10-11-2019 10:30 AM

How about just get the whole rear wheels package?:https://www.ombwarehouse.com/5-steel...-sprocket.html
It is about $115, but it comes with the entire wheel/hub/bearing/wheels/tubes/tires set. Pretty great deal actually.
And trust me, when it comes time to change tires, you will want split rims

aka Larry 10-11-2019 10:36 AM

Quote:

Originally Posted by JTSpeedDemon (Post 534485)
How about just get the whole rear wheels package?:https://www.ombwarehouse.com/5-steel...-sprocket.html
It is about $115, but it comes with the entire wheel/hub/bearing/wheels/tubes/tires set. Pretty great deal actually.
And trust me, when it comes time to change tires, you will want split rims

If that was for a set of four I'd be all over it, but it's for just two. :(

Based on your recommendation I've been looking at other split steel wheels though, and I'd like non-studded tires if possible, This thing will be on pavement 99.9% of the time. What I'd like is a dirt cheap pair of used up slicks just for looks.

JTSpeedDemon 10-11-2019 10:40 AM

A set of 4 won't be that cheap.
You can get sawtooth tires for those wheels at www.bmikarts.com
As far as used slicks, you're on your own looking for those.

aka Larry 10-11-2019 12:33 PM

If I step up to a 5" wheel, how about these tires on these wheels?

JTSpeedDemon 10-11-2019 12:36 PM

The tire link just leads to Tractor Supply's home page.
Those wheels look good, just make sure you get some good tires suitable for a kart.

aka Larry 10-11-2019 01:00 PM

Not sure why the link didn't work, but the tires are smooth design 4 ply. Remember this isn't a high-speed kart. Via the on-line calculators I'm thinking about 20 MPH or so.

https://media.tractorsupply.com/is/i.../1128247?$456$

JTSpeedDemon 10-11-2019 01:02 PM

As long as they're about 4" wide for a 5" rim, those should work really well.

aka Larry 01-02-2020 07:31 AM

The build is on!

Over the holidays I purchased the steel tubing and have been steadily sourcing other parts. So far I've ordered the cooler, 212cc engine, wheels, tires, brakes, throttle controls, sprocket, clutch, spindles, and parts of the steering system.

Assembly begins this weekend. WooHoo!

JTSpeedDemon 01-02-2020 07:36 AM

Yeah! :thumbsup:
Can't wait to see what you have planned!

aka Larry 01-02-2020 07:45 AM

A few questions for you...

I've watched about 10 videos on the Predator governor removal. I can't understand why you'd want to open the crankcase to remove the gear? Why not simply disconnect the external arm and re-do the throttle return spring?

Also, even though the tires are tubeless, I assume I have to use an inner tube with a split wheel? Can the wheel's seam be sealed to avoid using a tube?

JTSpeedDemon 01-02-2020 10:40 AM

Some VanK racing split rims have a seal that is bolted between the rim halves to allow for tubeless tires on split rims, but those probably aren't what you bought.

As for the governor, you can bypass it externally and get the same speed, but then you have to consider that you now have a plastic gear spinning inside the crankcase at significantly higher speeds than it was designed for. Some people have bypassed their governors and run them like mad without problems, but plenty of people have also had their engine blow up catastrophically due to a bypassed governor.

It's not that hard to fully remove it, so it's always suggested to.
A fully removed governor also makes it easier to change to a slide carburetor, wild cams, super stiff valve springs and the likes later.

madprofessor 01-02-2020 12:19 PM

Keeping it simple.......
 
Clearly you're doing a simple build, given that you're doing single-wheel drive as opposed to live-axle dual-wheel drive. Single-wheel braking too.
If you're going to be sitting on a Yeti you'll be too unstable to handle the speed of a ungoverned engine, and you'll get more than 20 mph even with the governor still working. Remember, the governor only limits your top end speed, it has zero effect on your power up to 3600 rpm.
If you later put in a safe seat, then want more top speed, disconnecting the governor linkage on top of the engine will do it. The chances of lunching a whopping $97 engine because you weren't willing to crack the case open, pull the guts out, regasket everything, etc. is not worth the work to me. I've left the brand new cases of 2 of those engines untouched, linkages disconnected only. Just know this:
The factory cast iron flywheel can blow apart at excessive rpm, cutting through the housing cover and all the way through your leg too.
I depended on the weak factory valve springs to float from 5200-5500 rpm on my first one, preventing excessive rpm. My current one got a $86 PVL billet flywheel to go along with its new 22 lb. valve springs, because "Ol' Stumpy" is not a nickname I want.
With a lot of go, you need a lot of whoa. Consider upgrading to 2-wheel braking for safety sake. Lock up that one wheel on wet pavement, then pucker up to kiss the bumper of that parked school bus.
My excessive engine means 6" wheels will still do wheelies, but your smaller choice wheels will indeed give you more low end power over a 6", and less top end. Vice versa when going larger. Split rims with tubes only!, no tire-changing machine needed. Get L-shaped tube stems.
FYI: For max strength I'm using straight-thru 1" live axle on my 6" split rims rear, and 3/4" "axles" (the important part of the spindles) in 3/4" NOT EXTENDED FLANGE bearings in the 6" fronts. Speed + curb or pothole = bent stuff.

aka Larry 01-04-2020 05:45 PM

Quote:

Originally Posted by madprofessor (Post 539566)
Split rims with tubes only!, no tire-changing machine needed. Get L-shaped tube stems.
FYI: For max strength I'm using straight-thru 1" live axle on my 6" split rims rear, and 3/4" "axles" (the important part of the spindles) in 3/4" NOT EXTENDED FLANGE bearings in the 6" fronts. Speed + curb or pothole = bent stuff.

Got my tires in today. For some reason stupid me thought a split rim with a tube would be a piece of cake for installing the tire. I used dish soap on the tire, and assumed it would just slide right on, but with all my might that SOB just won't go on there.

What am I missing?

JTSpeedDemon 01-04-2020 08:16 PM

Try pouring lighter fluid around the bead, igniting it, then quickly putting air in it. Or maybe just leave the air hooked up while igniting the lighter fluid. Of course, make sure the rim halves are bolted together SECURELY, or you may end up with killer flaming metal frisbees!:eek:
Ok, maybe that's a bit dramatic, but be careful nonetheless.

aka Larry 01-04-2020 09:05 PM

No, what I mean is I can't get even one half of the split rim into the tire. I assumed it would just slip right into the tire, but it doesn't. The tire is a tubeless type, but from what I've read, it shouldn't matter as long as the tire is the correct size.

landuse 01-06-2020 03:22 AM

Welcome!

madprofessor 01-08-2020 11:42 PM

Guess again, tubeless......
 
You've definitely got the wrong tire for that rim, as that tire has a very precise bead size, angle, depth, etc., and your rim is basically a pressed out generalization. Wasting your time anyway, tube-type tires (if you had them) are just supposed to swell up as the tube inside does, and never "pop" onto a bead. In fact, I wouldn't consider the outer circumference of a split rim to be a "bead" at all. Now if your tire will just swell up with the tube and sit comfortably in one place, forget about the bead of the tire and the nonexistent "bead" of the split rim, then just be happy at 30-35 psi and run them.


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