Total beginner looking for direction and advice

[Crockett87]

Hey all.. I've dreamed of making a kart/buggy for a while and it's about time I did something about it.
I don't have a wealth of mechanical knowledge but I know enough to usually figure it out. I work as a millwright so I'm familiar with gearboxes, bearings, belts, pulleys, sprockets and chains but by no means a master.
I've just got my hands on a Champion 6.5HP, 196cc motor and now I need the rest lol
I'm looking to build an on/off road kart/buggy type unit.. Speed isn't my goal just fun this time around.. I want to be able to do gravel roads, grass, some hills etc. I have access to a metal fab shop(no machining) so the frame, brackets and everything I can make myself.. Hubs and pulleys I will have to source.. But I figured before I start building a frame I would get a handle on all the mechanical stuff and figure out the drivetrain.
I'm looking for some do's/don'ts, pro's/con's and just general advice on what I've gotten myself into lol.

From all the research I've done so far I've figured out a torque converter/cvt is probably best for my needs.. If I could get a drivetrain for dummies lesson though that would be appreciated.. Pros and cons of mounting arrangements.. Proper gear ratios.. Power production. That kind of thing

Thanks for all your help in advance
~crockett


Sent from my iPhone using Tapatalk - now Free

 

[KartFab]

For your drive train you will need
Engine
30 series torque converter
Jackshaft
Jackshaft mounting plate (what the motor sits on top of)
Two 5/8" bearings that the Jackshaft will spin in
Jackshaft sprocket
3/16" keyway for Jackshaft sprocket to sit in

Axle sprocket 1" w/ 1/4" keyway #41 pitch
Chain (#41 or 420 pitch will work on a #41 sprocket

Keyed hubs w/4"x4" bolt pattern
1" keyed Axle anywhere from 36-42" long is ideal

8" rims w4"x4" bolt pattern
Tires I would suggest anywhere from 18" to 22" knobby (eg 18x8-11)
Get disk brake. A 6-7" for 18" tires or a 8" disc for 22"
Mechanical disc is cheaper and works fine, but lots of people like hydraulic.
Axle bearings (1")
Axle bearing flangettes
That should get you started

You want a 6:1 ratio for 18" tires and probably a 7:1 for 22"
Eg 10 Jackshaft teeth and 60 axle sprocket teeth

Get some of your stuff from bmikarts.com

Good luck!

 

[Crockett87]

Thanks for the info.. With my 196cc..6.5 hp motor.. I'm guessing 4-500lb total weight with driver.. I'm 250lb and I'm going to try to keep frame as light as possible. Am I going to have enough power to do anything or do I need a bigger motor?


Sent from my iPhone using Tapatalk - now Free

 

[Half-breeder]

Well, looks like you got the 'fever'

IMHO... unless you have a 'special' type frame in mind... Id attempt to get ahold of a 'factory' frame your happy w/ from CList or someplace like that. Reason... off road karts(buggys) tend to be 'larger'= more math/work/mats, than your average 'yard-kart' or race kart. If your goal 'is' an 'original' yard bomber... then theres alotta guys on here that have the knowledge of such endeavors. I personally figure factory=built(no build work/time), but theres no saying it cant be 'improved' upon(upgraded)... My build is an example of this theory.

To calculate your speed use this.

Yes a TC is a good idea... but if you go w/ a cent. clutch w/ a JShaft... use this.

If you happen to make/get a kart w/ front facing steering... read this. Its a 'simplified' way to get done 'proper' Ackermann geometry.

Hope your karting fever is as enjoyable as it is/has been for others on here. Keep us informed and post as many pics as possible(more details) and a vids are GREATLY accepted and useful(helps others and gives ideas).

 

[OzFab]

For offroad use, I'm gonna suggest a 1 1/4" axle, slightly more difficult to bend...

Apart from that, garn pann seems to have a comprehensive list there...

 

[Crockett87]

I plan on building my own frame only because its cheaper for me. My boss is pretty awesome and doesn't charge me for materials. So I can custom fit the kart to me and it won't cost me anything


Sent from my iPhone using Tapatalk - now Free

 

[Half-breeder]

Nifty... now all you need is a 'plan'. These guys have plans fav'd. They can make suggestions/links... another resource of knowledge of those things is T-man. He's got youtube vids of builds and procedures/steps/gears/calculations...etc. He's a member on here...(just never seen him post since I been a member).


Infact he's building a 'buggy' now...."Fullscreen" machine... thats the name of it...

 

[Crockett87]

Thanks for the advice all I appreciate your insights.. I plan to start getting parts after I've done a little more research on everything and have a solid set-up in mind. I figure if I mock up my drivetrain first being that those are the parts I'm least familiar with I can build my frame around/ to suit the set-up of that.
Couple other questions..
The output shaft on a TC is the jack shaft?
I'm unfamiliar with this stuff so forgive me if I sound like a dumb*ss..but bear with me... The input pulley on the TC connects directly to the crankshaft of the engine... And the output pulley rides on one end of the JS while the driven sprocket is on the other end.. Then chain connects it to the drive axle?

And is there any thing wrong with pillow block bearings vs. a bearing in a flangette? For shaft or axle applications?


Sent from my iPhone using Tapatalk - now Free

 

[Half-breeder]

The input pulley on the TC connects directly to the crankshaft of the engine... And the output pulley rides on one end of the JS while the driven sprocket is on the other end.. Then chain connects it to the drive axle?

And is there any thing wrong with pillow block bearings vs. a bearing in a flangette? For shaft or axle applications?

Correct on the TC JS question...

ive heard pillow blocks are more than adequate.

 

[icebox187]

yeah.. pillows are tough. also see my threads, I think I have something listed in fs that will work very well for your drivetrain setup. From what I gather, you want a trailrider... you should probably go with a 16 inch balloon/knobby rear if you aren't going to run any rear suspension. If you want to get through mud you may want to go bigger. For this type of kart/buggy, you want to figure out the tire size, and then figure out what size gears to run. 5:1 gears won't put that 6.5 hp on the ground very well with 20" tires no matter what cvt you run.

 

[OzFab]

And is there any thing wrong with pillow block bearings vs. a bearing in a flangette? For shaft or axle applications?

Your choice of bearing mount comes down to two things:
1. Personal choice
2. The application

To use pillow blocks, they must be mounted to a level, flat surface, as do flanges but, with a flange, they are bolted to a vertical mount which is then welded to the frame.

Pillow blocks are mounted horizontal so, unless you use reinforced square tube which is wider than the mounts, you need to bolt it to a length of angle which is then welded to the frame. This acts as an advantage (or a disadvantage, depending on how you look at it) as the axle can then be mounted closer to the frame; with a flange, you're governed by its height...

 

[machinist@large]

I plan on building my own frame only because its cheaper for me. My boss is pretty awesome and doesn't charge me for materials. So I can custom fit the kart to me and it won't cost me anything

So we can take it that you're comfortable with your welding/ fabrication skills?

Thanks for the advice all I appreciate your insights.. I plan to start getting parts after I've done a little more research on everything and have a solid set-up in mind. I figure if I mock up my drivetrain first being that those are the parts I'm least familiar with I can build my frame around/ to suit the set-up of that.
Couple other questions..
The output shaft on a TC is the jack shaft?
I'm unfamiliar with this stuff so forgive me if I sound like a dumb*ss..but bear with me... The input pulley on the TC connects directly to the crankshaft of the engine... And the output pulley rides on one end of the JS while the driven sprocket is on the other end.. Then chain connects it to the drive axle?

And is there any thing wrong with pillow block bearings vs. a bearing in a flangette? For shaft or axle applications?

There are many ways to set up a TC/ JS combination; for your size engine you might be happiest with one of the 30 series knock off's that integrate the JS into the mounting plate that bolts to the output side of your engine. It makes for a pretty tidy package, and helps minimize the head scratching because it's pretty much a plug & play.

Heavy duty cast pillow block bearings work well in karts, and as a millwright you're probably as familiar with them as I am (machinist/ CNC machinist/ machine builder/ machine repairman here). The thing I like about pillow blocks over sheet metal flanged mount bearings is that they usually come with grease zerks and a better selection of high grade seals. Use what you're comfortable with, and you should be fine.

Fabroman (aka Tony) is correct about looking at a 1 1/4" axle; depending on what your idea of play is, it can be a REALLY good idea....

 

[Crockett87]

Thanks again. And yes I am comfortable with all the welding and fab work ill need to be doing.. 50% of my job is maintenance.. Belts and bearings, etc.. The other half is all fab.. And I've taken advantage of our shop on many occasions lol.. I've got a bush bumper on the front of my truck that has taken a few deer and even a cow.. It's a little worse for wear from the cow but the welds didn't break lol...
I was thinking pillow blocks mainly because I can probably grab them from my shop for free and the ease of greasing.. I'm planning 1 1/4-1 1/2 square tubing .125 probably.. And then take 1/4-3/16" plate and weld that to the out side of the frame and gusset for my axle bearing mounts.. I still haven't decided if I'm going to go with suspension or a rigid mount yet.. Ill determine that when I start building the frame and if cost allows... I want to see what I can find for scrap atv parts In the next month or so and go from there... The kart is going to be urban/trail used mostly.. I imagine 80% of the time will be gravel or asphalt roads but I want the ability to do hills and rougher terrain as well.. This first go round is mainly proof of concept/ability for me and then after its done and works I can upgrade/tweak as I see fit. Nothing to complicated to begin with until I know it'll go.. After that I can play with gearing, upgraded suspension etc and see what kind of monster I can create hehehe


Sent from my iPhone using Tapatalk - now Free

 

[mckutzy]

Hey cool another person with a champion motor. they are pretty good motors, can run most of the clone parts on them, have better rockers and other stuff on the head.

IF that is the material you are going to use, that is going to weight a ton. A bit much for that motor.

1" .120 wall would be a better choice, a little lighter.

 

[landuse]

Nifty... now all you need is a 'plan'. These guys have plans fav'd. They can make suggestions/links... another resource of knowledge of those things is T-man. He's got youtube vids of builds and procedures/steps/gears/calculations...etc. He's a member on here...(just never seen him post since I been a member).


Infact he's building a 'buggy' now...."Fullscreen" machine... thats the name of it...

He posts, but just not too often....

 

[OzFab]

I'm planning 1 1/4-1 1/2 square tubing .125 probably.. And then take 1/4-3/16" plate and weld that to the out side of the frame and gusset for my axle bearing mounts..

If you use square tube, you can mount the block directly to the frame but, you will need to reinforce the inside of the tube to prevent crushing

I still haven't decided if I'm going to go with suspension or a rigid mount yet.. Ill determine that when I start building the frame and if cost allows...

Here's an idea: If you want the kart to have suspension but can't afford the shocks right now, build it with all the swinging parts & fit a length of tube in place of the shocks & replace them with shocks as you can...

It's a lot easier to undo a few bolts than reconstruct the entire frame

 

[Crockett87]

Yeah.. It's easier to weld the plate to the frame than mess around with reinforcing the tube.. But that's only if I go rigid... How do most karts tackle rear suspension? Is it shocks on swing arms? And then how does the axle set up normally go?
I can handle a straight axle and wheel hubs but when it comes to suspension I'm out of my comfort zone?
Also I've been looking online(only bmikarts.com)
For prices and availability.. I've found torque converters but I can't tell which is 20,30 series etc.. I see the parts listed as 30,40,500 series but those are separate and I was looking to get a whole unit just to make it easier. What is the difference in the series and how do I know what I'm looking at?


Sent from my iPhone using Tapatalk

 

[OzFab]

Yeah.. It's easier to weld the plate to the frame than mess around with reinforcing the tube.. But that's only if I go rigid... How do most karts tackle rear suspension? Is it shocks on swing arms? And then how does the axle set up normally go?

Using a solid axle, a swingarm is the usual setup; simply create the rear end of the frame as a separate unit, attach to the front frame with pivots & mount the shocks between the two, usually on an upright bar.

Of course, the more expensive but better way to go is independent where you would have a centre section connected to the front frame for mounting the engine & axle centre & trailing arms to mount the wheels.

I've found torque converters but I can't tell which is 20,30 series etc.. I see the parts listed as 30,40,500 series but those are separate and I was looking to get a whole unit just to make it easier. What is the difference in the series and how do I know what I'm looking at?

The differences between them are size & HP rating; a 30 series is used mostly on small honda clones, 5hp B&S, etc with a 3/4" PTO shaft & a power output under 8hp. 40 series & up are for larger, more powerful engines. If you intend to used a Predator 212cc engine, you need a 30 series tav2.