4WD Hunting/Utility Buggy Build?

J.W.

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Y’all walk me through this…

I have never built a kart before, so I’m looking for advice.

I want to build a lightweight two-person tube-frame utility buggy that is still somewhat trail-capable and has part time 4wd. Think Willys M38-sized, maybe longer. Probably independent suspension all around. A flat bed or tilt bed for hauling light loads (a deer or a hog or two, maybe a few sacks of corn, etc) would be nice.

I have some experience working on and wheeling jeeps, and was a robotics coach (lots of chain, sprockets, gears, wiring, CIM motors, and fabri-cobbling). I can CAD a little and weld pretty decently (at least MIG and FCAW). I don’t have the means to get a lathe or mill right now, but I do plan on getting a decent tube bender and notcher if I go through with this.

I was thinking 1.5” 120 thou tubing should be stout enough if it’s properly braced and gusseted, right?

For power I was looking at the Predator 670 or a DuroMax 999. Getting power to the wheels is where I’m lost, as I have zero experience with CVTs, but here’s what I’m thinking:

Driving pulley to driven pulley via belt (CVT), with that driven pulley on the input shaft of a FNR gearbox. Output shaft of FNR to a divorced small transfer case (maybe from a Samurai?) where 2H, 4H, 4L can be selected. Shafts from t-case to diffs (probably UTV take-offs).

Will a Comet 780 hold up to those engines? Seems like a stretch, but I have zero experience with anything CVT. I also thought about a RZR 800 or 1000 CVT.

Reverse is a must, and I’m not sure about the best way to go about getting it… I see FNR gearboxes meant for karts, but are they too light-duty? The RPM and Quaife boxes look nice but holy smokes… ‘spensive.

FWIW, I was wanting to turn some 28”-30” ATV tires, which may be a tall ask.
The other option I’ve been kicking around is to go electric, but I think that would be super expensive.


Any thoughts, ideas, or suggestions are appreciated.
 

vpd66

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It is really strange that someone has not come up with a budget build for something like your looking for. With UTVs going for $15000.00 and up and all the 4 wheeler parts around you would think someone would have tabbed something up.
 

Master Hack

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Yer gonna need a welder and some creativity.

while this doesn't meet yer design criteria, it meets mine, for a utility buggy/kart/thing.
Using my superior scrounging ability l was able to build this beauty for under $500.
its ugly as sin, but perfectly functional. It sees daily use here at the Mt. Top Labaratory.

959963D4-BC9A-4EAB-94A0-8D4736F43217_1_105_c copy.jpg
 

J.W.

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Ok, so an update:

I was just given a '09 Yamaha Rhino 700 FI that has not run in a few years. It has been sitting in the weather for that whole time. Apparently it would start, but would die as soon as it was put into gear. I am going to see if I can get the engine running. I should have a new ignition switch and key (key was lost) in my mailbox when I get home. If the engine will start and there aren't any other issues that have accumulated whilst sitting outside, I think the whole dying when put into gear issue is probably in the wet clutch. Kind of a pain to get to, but shouldn't be a hard fix. If I can get it going, I could run it as-is for a while, but I think I would ultimately like to stretch it about 18". That would give me room to put some folding jump seats between the rear wheels and the front seats. I have an idea on how to do that, but it would probably mean swapping for a lower-profile fuel cell. I would also need to extend the rear driveshaft, which might require a trip to a machine or driveline shop.
 

J.W.

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Update:

Siphoned out the gas in the tank and put some fresh gas in.

Starter turns. Will not crank.

Plug has spark but I replaced it with a new NGK anyway.

Piston moves freely, it’s not seized.

I pulled the fuel hose off the fuel rail, and there’s plenty of gas getting to the fuel rail. The injector looked a little more difficult to get to and it was getting dark, so I didn’t pull it yet, but I guess that’s next.

If anyone has any other suggestions, I’m all ears.
 

lug-nuts

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I made a DIY injector cleaner with a rubber hose necked down to fit the carb cleaner straw. get the battery and 2 leads to cycle the injector open. Then just put the hose on the injector, pressurize it, and energize the lead to the injector. Dont leave the injector open for more than a few second at a time, and it'll work great.
 
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