Picked up this one wheel drive, scrub brake kart for 35 bucks at a garage sale. Paid another 15 for parts. Good points was it was all there, new tires, and a newer clutch. The engine test fired okay, 3.5 hp briggs. Throttle and brake were screwed up, clutch didn't fit the engine, and engine was major hillbillyed on the governor/throttle linkage.
Shaft on the 3.5 was shot, so I grabbed a 5hp that was on a log splitter. Now I HATE, and I mean HATE siphon carburetors/diaphragm carburetors. Yet I still cleaned and rebuilt it. It ran okay, but could not get the idle rich enough without choking out the high speed, and it constantly stalled.
So I grabbed a bunch of carbs/adapters, and managed to put a real carb on it. It's from a 8hp side shaft(old go kart engine), and has an idle and main adjustment. Used an adapter from a tecumseh (I think), and bolted it on. Then I even manged to hook up the original governor/throttle, buy cutting it off the old gas tank, and remounting it to engine.
Then built a gas tank mount, and mounted old tank on it(no idea what it's from). Now I have a great running 5hp, tunable carb, and governor to keep the rpms down for the kidde's. Still have to mount air filter.
Fun part is other than a chain, plug, and carb kit, all the parts I had laying around. I really didn't want to spend money on this project...
Top speed is a whooping 18mph. But man, is it a fun 18 mph, and it's plenty fast for the yard. Governor spring is a little weak, I could tweak it and get another 5mph, but like the rpms being slower for the kids.
I really don't know how you would upgrade the brakes, since the rear tires are not connected. I have a couple ideas, but they involve a decent amount of work and money to do. Maybe we'll bolt a couple pieces of rubber on the scrub brakes.
I'm pretty darn proud to bolt on a completely different carb, and make the governor work.
I'm throwing an air filter on, and calling this project done. Too many other projects to work on. It runs nice, and should be pretty reliable.
Well- you've done well so far- be proud! You are indeed correct in thinking that it will take some engineering on your part to retrofit that thing with better brakes. Sometimes you (I, LOL) take these things for granted, and as a given. The kart I am working on now, was originally set up as a 1-wheel-drive with all the mechanical nightmares that go with it. Shortly after getting it, I whipped out the grinder and hung a live axle in there... Disc brakes, etc.
This kart just got a major upgrade. New motor, 5.5 OHV briggs. Came as pretty much a parts engine, new plug, carb worked on, governor put back together, gas tank, and then had a random chunk of metal I had to get out of it.
New bearings and sprocket for the one wheel drive.
Brakes got worked on a little more, they were hanging up.
Frame was bent, so straightened that out, and welded in some reinforcements.
Here's a video with all the changes, and some driving time!