Go kart build assistance!

[jbreeden69]

Hey guys,

I'm new to building karts but I have done my research however there are just some questions that I can;t seem to find answers to, so I decided to go ahead and post a thread here. I recently acquired a Buggy frame, it's a two-seater (Can fit two adults, I'm 6' 1" 220 and my wife can fit right along side in it), I'd say frame is somewhere in the neighborhood of 150 - 200 lbs. I'll try to post some pics as soon as I can, but headed out of town this morning.

I was contemplating whether to build out a PRedator 212 or go with with a 420CC. Pros and cons either way, but I think I'm going to go with a 420 (40 series torque converter) just for the option of being able to upgrade it for more overall torque. My frame currently has a 32 tooth sprocket on the drive Axle, I'm pretty sure I'll need to go a jackshaft route, however need to figure out all of my components first.

My First major question that I can;t seem to find any answers on, is the wife really wants a reverse gear. I can find small-ish gearboxes all day long, and I can find one on amazon that says rated for up to 13HP, but I fear that once this engine has been built out it will shred this gearbox. so my question for you guys is, what are people using on bigger engines to get a reverse gear? I can;t seem to find anything, but maybe I'm not searching with the right keywords.

Appreciate the feedback, I'm sure I'll have other questions, but for now this is my main one.

 

[7thofa2nd]

You should probably just scour all the youtube videos. There you'll see a lot of pros and cons.

 

[madprofessor]

Replacing that 32-tooth axle sprocket should be your first step no matter what motor you use.
My own personal preference is putting a sprocket hub on the axle just the one time, then swapping around 6-bolt split sprockets from there. That swap takes about 5 minutes, and split sprockets can be had for less than $15 anytime.
For your motor, a Predator 212 can be had at Harbor Freight for $140 any day, or $100 on sale with a coupon like my current one. Mine's been hotrodded to 15+ hp., but that was over $300 more in parts. Unless like me you just want the fun of building out a motor, a 13 hp. ready-to-run 420 might be the right choice for you at $400 on any day.
The 420 weighs 38.5 lbs. more out-of-the-box than the 212, but that's not much of a deterrent considering the total kart weight.
Have no clue to offer about gearboxes.

 

[7thofa2nd]

Replacing that 32-tooth axle sprocket should be your first step no matter what motor you use.
My own personal preference is putting a sprocket hub on the axle just the one time, then swapping around 6-bolt split sprockets from there. That swap takes about 5 minutes, and split sprockets can be had for less than $15 anytime.
For your motor, a Predator 212 can be had at Harbor Freight for $140 any day, or $100 on sale with a coupon like my current one. Mine's been hotrodded to 15+ hp., but that was over $300 more in parts. Unless like me you just want the fun of building out a motor, a 13 hp. ready-to-run 420 might be the right choice for you at $400 on any day.
The 420 weighs 38.5 lbs. more out-of-the-box than the 212, but that's not much of a deterrent considering the total kart weight.
Have no clue to offer about gearboxes.

YES... definitely make a sprocket change. A 32 tooth is practically highway driving, but it would be a dog at takeoff.

 

[jbreeden69]

Thanks for the replies guys. I do like the split sprockets, I have that on one of my other karts. Ill have to do some research to find a sprocket hub that will fit the axle (1.5 inches), but I do think that is where I am headed.

Do people even worry about putting reverse on big karts? I had an idea, but not sure how it would work. Has anyone ever tried a second engine, like a 212, mounted in the opposite direction so that it runs in reverse, with a centrifugal clutch hooked in the drive of the kart. The idea would be that when it was running, the outer portion of the clutch would free spin in the opposite direction with the kart going forw as rd, and when and if you need reverse, the kart stops and you could throttle the second engine to move it backwards? Obviously it would be independent throttle from the first engine, maybe a hand operated....

 

[msrfan]

Thanks for the replies guys. I do like the split sprockets, I have that on one of my other karts. Ill have to do some research to find a sprocket hub that will fit the axle (1.5 inches), but I do think that is where I am headed.

Do people even worry about putting reverse on big karts? I had an idea, but not sure how it would work. Has anyone ever tried a second engine, like a 212, mounted in the opposite direction so that it runs in reverse, with a centrifugal clutch hooked in the drive of the kart. The idea would be that when it was running, the outer portion of the clutch would free spin in the opposite direction with the kart going forw as rd, and when and if you need reverse, the kart stops and you could throttle the second engine to move it backwards? Obviously it would be independent throttle from the first engine, maybe a hand operated....

I would think you wouldn't need big power and speed for reverse. Peerless transmissions offer a lot of configurations with low geared reverse like used on garden tractors.

 

[madprofessor]

Yes, the bigger and heavier the kart, the more you would appreciate a reverse gear when up against something.
A friend asked my help on that with his bare bones kart long ago. We took an old rim with a bearing in it and a half decent tire on it, mounted it in front of the left rear wheel of the one wheel drive kart.
We just made a swing bracket of some rod and angle iron, with the wheel a little sloppy on the rod but okay.
A lever held and locked the tire up off the ground and away from the tread on the kart tire, then slid it down and and a little bit back to contact the driven kart tire.
The kart tire would try to climb up the swing tire, and by scrubbing make the swing tire run backwards with the kart tire spinning forward and not really in contact with the street.
We did manage to adjust it to work fairly well on the street, but was iffy on dirt, and useless in sand.