Mini-buggy plans/ideas, need feedback please!

[RedRider_AK]

Hey guys. I've once again been brainstorming ideas on how to build a mini-buggy or mini-rail, using only common ATV parts and some basic square tubing, etc.

Anyway, here's my main ideas:

- Home build a main chassis. I have several friends who are fairly good at welding, and I will actually spend good money on tubing to make the chassis nice and strong. I expect this kart to be a single-seater, with approximately a 250 to 500 four-stroke engine (shifter and chaindriven, more on that ahead). Can anyone recommend a gauge and size of tubing I'll have to get to get the maximum amount of strength and not TOO much weight for the small engine to push around? I'm thinking something like 1" square tubing, maybe about 1/16" to 1/8" thickness, probably mild steel. Would that be sufficient? I prefer square tubing because it's easier to weld onto, you don't need to notch the tubing (we don't have a drill press or any serious machine shop implements).

- Use a four-wheeler rear suspension for the drive system. Most likely an IRS system, with some kind of drive system rigged up to fit. What rear drive units can handle to most abuse without breaking? Personally, I was going to use King Quad front diff. units in the back of the kart, with home-made extended arms and axles. I estimate they'll probably grenade if you use a large engine with them, though, so it's not my first choice. I have 4 King Quad 300's, though, so I have to do something with them, maybe make a couple really small beginner's karts, or something. Would a Sportsman 500 rear unit and engine combination work all right?

More on the King Quad system: I would use the stock front driveshaft that goes from engine to front diff, and on that driveshaft I would weld a sprocket hub from any solid axle sport type quad (Quadsport 230?) and then mount a chaindriven engine sideways in the chassis to match it up with the sprocket. Maybe a QuadRunner 250 engine or something of that type. The shifter would be operated with linkages.

- Front suspension will probably consist of Quadracer 250R a-arms, extended with steel tubing slipped over the arms and welded in position, and set up with long-travel Polaris shocks or snowmobile shocks of some kind.

- Dual brake pedals, one for the front, and one for the back. The rear pedal will be able to depress on it's own, for setting up drifts, and the front pedal will connect both of them for maximum stopping power with one foot.

Does anyone have any ideas or suggestions? Please don't suggest things that are expensive ("You should stick a CBR929 motor in it!" or "Why don't you just part out an Outlander 800 and use that as the drivetrain?" comments will make me cry :cry: )

Thanks for the help!

[84honda200s]

ok homie. i would use 1/8 inch walled tube steel probably around 3 inches x 1 - 2 or something like that. if you go 1x1 it may "bounce" as you riding. if it bounces around too much it will bend then break. so id go with something taller than 1 inch. i know its not a cheap way to go man but you will thank me later. ive learned that lesson the hard way a couple times.


now for the rear end. do you have any old ricer cars around ? ive herd of guys that used the front ends out of front wheel drive smaller cars. cars like the civic, neon, aspire, metro, ect... it would probably take allot of work but if you have a old small car around its freebies. plus they are already set up for being the drive line.


ill think some more man and do some searching online and see if i can find some more info. i know ive seen it done before.

[RedRider_AK]

ok homie. i would use 1/8 inch walled tube steel probably around 3 inches x 1 - 2 or something like that. if you go 1x1 it may "bounce" as you riding. if it bounces around too much it will bend then break. so id go with something taller than 1 inch. i know its not a cheap way to go man but you will thank me later. ive learned that lesson the hard way a couple times.

All right, so it'll be rectangular tubing? I was just thinking, this machine isn't going to be going very fast (it all depends on the engine and driveline I'm using in it) but most likely around 45 to 60 mph at the very most. The weight will hopefully be maybe 100 or so pounds more than a typical large utility quad (around 600 or 700 lbs), and I'm going to be using plush shocks so it'll be a nice cushiony ride. What about 2" square tube, I really think that's enough for the actual frame, and maybe 1.5" tube for the roll-cage and bumpers.



now for the rear end. do you have any old ricer cars around ? ive herd of guys that used the front ends out of front wheel drive smaller cars. cars like the civic, neon, aspire, metro, ect... it would probably take allot of work but if you have a old small car around its freebies. plus they are already set up for being the drive line.

I was thinking about that myself, but I think it'd be too much hassle to rig that sort of thing up. I need something small and agile, not something the size of a regular compact car and with terrible suspension. I doubt my available engines (200 to 500 four-stroke auto-clutch) will have enough balls to actually push that kind of drivetrain anyhow. Now, if I ever got my hands on, say, a Sportsman 800 or so, then we'd have something to talk about... :twisted:


Thanks for the feedback bro, it's food for thought!

[84honda200s]

I was thinking about that myself, but I think it'd be too much hassle to rig that sort of thing up. I need something small and agile, not something the size of a regular compact car and with terrible suspension. I doubt my available engines (200 to 500 four-stroke auto-clutch) will have enough balls to actually push that kind of drivetrain anyhow. Now, if I ever got my hands on, say, a Sportsman 800 or so, then we'd have something to talk about... :twisted:


Thanks for the feedback bro, it's food for thought!




the drive line on the aspire is very small. im surprised its even on a car. the aspire it only a 70 hp car. the shafts are only about 2 inches round if that and are very lite weight. trust me i worked on the front end of one a few times. the suspention part will be a doozie trying to get figured out. but other than that it should work.

[The Goat]

if you grease that engine and rear end on that sportsman it will be indestructible.

another option is like he said...go in a junk yard and pick up a totaled (from the rear) civic for hardly anything. 100+ hp and bulletproof. put the front wheel drive in the rear with the steering locked...fab your own steering. voila.

not quite that easy...but then again...not tooo hard. shouldn't be more than 4 or 500 bucks for the civic.

[RedRider_AK]

the drive line on the aspire is very small. im surprised its even on a car. the aspire it only a 70 hp car. the shafts are only about 2 inches round if that and are very lite weight. trust me i worked on the front end of one a few times. the suspention part will be a doozie trying to get figured out. but other than that it should work.

Hmmm, maybe just use the engine and transaxle out of a rice car, extend the driveshafts out farther, and custom make A-arms for them, then bolt the stock spindles to the custom arms? That would work pretty good if I was looking for a larger sandrail project.

[RedRider_AK]

if you grease that engine and rear end on that sportsman it will be indestructible.

So you're saying to use the Sportsman 500 engine and rear end? All right, I've got one of those sitting outside my house as well, I'll see if I can't get it running or maybe just strip the rear end out of it.

[Nick_R_23]

Ive thought about doing something similar to this and I have a fairly good idea of how I think I would want mine to be built...

I have whats leftover from a junked 91 Polaris Trail Boss 350L 4x4. Its basicly the swinger, tranny, and motor but the motors been used now. The frame was cut out about half way up the posts, so theres basicly an engine cradle right there. (if this is confusing I can post pics later). What I would do is use this cradle, tranny, and swinger (solid axle), because the tranny gives me R, Hi, Lo, and N. It also is belt driven so that gives me a wide range of motors I can choose from, anything that is belt drive really. Plus, this tranny is chain driven 4x4, so I can make the kart 4x4 if I want to.

I would keep it all in the cradle, because thats a good base to start welding from, and everything lines up already. I would set it up so that the motor is sitting behind or directly under you, no farther forward then that. For the front end, I would probably find another junk polaris with the front 4x4 setup. That way its got front independant, and I can have 4x4 if I so choose.

Also another good thing about using this setup, is that the rear brakes are hydraulic and mounted on the transmission, and WILL lock up your rear end for some nice drifts if thats what your after. The front brakes are also hydraulic and theres one on each wheel. They are already set up the way you want them, theres a pedal that stops the rear only, and the front brake stops both front and rear.

I personally would stay away from the differentials as much as I could, unless this is a hardtail, its only going to complicate it and make things harder.

HTH

-Nick :TrikesOwn

[RedRider_AK]

I have whats leftover from a junked 91 Polaris Trail Boss 350L 4x4. Its basicly the swinger, tranny, and motor but the motors been used now. The frame was cut out about half way up the posts, so theres basicly an engine cradle right there. (if this is confusing I can post pics later). What I would do is use this cradle, tranny, and swinger (solid axle), because the tranny gives me R, Hi, Lo, and N. It also is belt driven so that gives me a wide range of motors I can choose from, anything that is belt drive really. Plus, this tranny is chain driven 4x4, so I can make the kart 4x4 if I want to.

I would keep it all in the cradle, because thats a good base to start welding from, and everything lines up already. I would set it up so that the motor is sitting behind or directly under you, no farther forward then that. For the front end, I would probably find another junk polaris with the front 4x4 setup. That way its got front independant, and I can have 4x4 if I so choose.

I personally would stay away from the differentials as much as I could, unless this is a hardtail, its only going to complicate it and make things harder.

I will agree with some of your points, but I mostly disagree with them. I wanted the differential in the back because it's much more compact suspension-wise than a swingarm, which would force you to stretch the back end of the kart out at least twice as long, because of the pivot point for the arm, etc. The differential and IRS system in the back would allow me to have a good amount of travel without the huge amount of space the swingarm would take up. Also, I want to have the seat as low as possible, which isn't possible with that chain drive for the 4wd. Can you imagine a chain running between your legs?! You'd have to raise the seat at least a foot, which means taller center of gravity, etc. I'd rather stay away from that.

I think I'll personally go with the King Quad and Sportsman differentials and IRS systems, because it'll just be so much more compact. Also, extending arms for them will be simple and easy, as will extending the axles themselves. Thanks for the ideas.