New kart project

[JHen]

So I sold some stuff I had laying around and raised some cash for a kart. It is going to be a full suspension kart, double a arms on the front and the rear will be a swing arm, pretty standard. The engine though will sit on its own little shelf behind the rider and won't bob up and down with the tires. I will utilize a chain tensioner I am going to make to facilitate adjusting to the changes caused in the chain. The tires are going to be
http://www.bmikarts.com/item/15-Super-Turf-Front-Tire-on-Silver-Rim-260045S-6942 obviously the rear tires for the rear.
It is going to be powered by a 7-8hp engine with a 12 tooth sprocket clutch going to a 60t sprocket. I will be using a mechanical disc brake system on an 8 inch brake rotor. It will be live axle straight across. The seat will be a standard lawn mower seat cause shipping on seats is expensive!

Here is the initial design idea:

It is 77 inches long from wheel center to wheel center right now. The seating area is 24 inches wide tapering down to 12 inches wide and is 48 inches long. I'm kind of tall at 6 feet and I don't like being scrunched up. The seat will be adjustable. The tubing is going to be 1x1x.083 and I'm considering making the bottom rail 2x1 for extra strength, though I'm not sure it will be needed.

I am going to make some changes, namely to the rear section. Going to make it a tad shorter and the swing arms are going to be made out of 2x1 rectangle tube. At the ends I will weld on 1/4" plate to mount a flange bearing block and the axle will run through the swing arm. That way I can get more ground clearance.

The shocks im going to use are just simple cheap mechanical shocks, each rated at 450 pounds with 2" of travel. Total suspension weight would be 1800 lbs then.

I hope to talk to a friend and utilize his machining tools to make a lot of the parts myself like the hubs, axle, and spindles. Now I'm just waiting on my tires and what nots to get here so I can get measurements from them so I can design the fine details like the spindle and suspension and spacers i will need to get the rear tires spaced from the frame the distance I want.

I plan to document the entire build for everyone's enjoyment.

 

[JHen]

Here is what I think I will use for the rear mount on the swing arm to mount the flange bearing block:

This is the bearing flange I plan to use, well not this exact one but something very similar.

 

[fowler]

should get a bike engine

 

[JHen]

I thought about that, but I don't want to go too fast. According to calculations, this will top out at 32, which is plenty fast for me. I just wanted a simple kart design. Get going too fast and I'll be inclined to add a roll cage and a better seat as well as a harness which takes the cost and complexity higher than I want to go.

 

[JHen]

Went and picked up a seat today from local Rural King, after disputing with a manager about the price because they had five of them on the shelf with a 42.99 price tag and they were ringing up at 79.99. I got it for the 42.99 price. Pretty good deal. It is very comfortable as well. Here is a picture of the seat. I would have taken a picture of it but my wife took the camera so this tiny picture will have to suffice. It stands about 14 inches tall and is about 21 inches wide.

I plan to mount it to an adjustable slider I ordered and mounting it so that the front is elevated at a 15 degree angle. This creates more of a bucket seat and it also makes it easier on your back since less of the force will be concentrated at the base going straight up your back and more like your lying down. This will put the seat back at about a 30 degree angle back from vertical in total.

 

[JHen]

Ordered the wheels and tires, seat slider (cause I don't feel like making one), sprocket (also don't feel like making one, though this is pretty much just a blank), brake rotor, which was like 3.25 so i figured may as well. Already have the clutch, brake caliper, and shocks. Only part left is engine, which is where I'm debating with myself the most on what to get. Then I can get measurements and start designing the frame details and then building!

 

[JHen]

Got me a kill switch now. Hurray for nickel and dime stuff! 3M Heavy Duty Metal Toggle Switch, rated up to 35 amps.

 

[JHen]

Picked up an engine today, a Harbor Freight Predator 212cc. 150 plus tax and a free 2 year replacement warranty to boot. Getting ready to inspect it and see what this thing is made of.

 

[jrmints1415]

you know the tires you plan on using will not work for a live axle unless you drill through the rim and axle and put a bolt through... also they are 5/8 bearing and im pretty sure you did not buy the axle or hubs yet. How do you plan on having your steering setup without steering parts?? As of how it looks now be ready to shell out about another 500 bucks, not to mention chain, steel, and paint. Also what kind of welder do you have?? Haha you still have a little more than an engine to get... Good Luck!

 

[JHen]

you know the tires you plan on using will not work for a live axle unless you drill through the rim and axle and put a bolt through... also they are 5/8 bearing and im pretty sure you did not buy the axle or hubs yet. How do you plan on having your steering setup without steering parts?? As of how it looks now be ready to shell out about another 500 bucks, not to mention chain, steel, and paint. Also what kind of welder do you have?? Haha you still have a little more than an engine to get... Good Luck!

Um, the tires I have for the rear are for the rear, and I think I said that.. yup right here

The tires are going to be
http://www.bmikarts.com/item/15-Supe...m-260045S-6942 obviously the rear tires for the rear.

Front:

Rear:

The rest of the parts I'm going to make myself, which I also stated in my original post...

I hope to talk to a friend and utilize his machining tools to make a lot of the parts myself like the hubs, axle, and spindles.

My welder is a Hobart 140. Steel is going to cost me like 70 bucks. I can get 10 feet of chain for 10 bucks and paint is going to be like another 12.

Next time you're going to be an ***, try to read the entire thread you're being an *** in.

 

[jrmints1415]

whoa there bro calm down, all i was doing was asking. Glad you cleared that up for me... Thank you.

 

[JHen]

whoa there bro calm down, all i was doing was asking. Glad you cleared that up for me... Thank you.

If I took you the wrong way, I apologize. It seemed like you were talking to me as though I were an idiot. Text is terrible sometimes at conveying meaning.

 

[jrmints1415]

haha i know what you mean! I just wanted to make sure you had all the parts sorted out with the build before you start... best of luck to ya!

 

[bighead]

Group Hug

 

[JHen]

Hehe

 

[JHen]

Got to work on making the rear axle bearing mount mounts. These will be welded to the sides of the rear swings arms and the axle will run through them. The bearing block flanges will then bolt up to these with 4 grade 8 7/16" bolts.

This is testing the fit of the bolts after I got the holes drilled for the bolts:

Here is where I have the pilot holes drilled for the hole saw arbor for the center holes:

Here is the center hole drilled and the bolt holes counter sunk. The finish is terrible on the countersinks though, but I don't think they show up very well:

And this picture shows what it looks like as you face the business end of the bearing down the rotating axis of the axle, kind of. Not perfectly over head but whatever.

Drilling the center 1.25" hole was super fun. The hole saw had horrible run out, like an 1/8" or more. I just let the plate flail around with the hole saw. It's not an important hole, just needs to be big enough for clearance.

Ran out of time but next is chamfering the center holes with a file and then cutting the pieces out. Then radiusing the corners on the grinder and bevel the edges on the plat and sand all the surface gunk off.

The only critical things on there are the bolt holes and they are near perfect.

I'm also playing waiting game on some parts I ordered from BMIkarts. I had two orders, one was some tie rod ends and the other was some wheels and tires, a sprocket, a brake rotor, and a seat slider. Still haven't gotten a shipping notice. Going to give them a call next week and find out what's up. Anyone else have a problem like that?

 

[JHen]

Got the axle mounting plates done. Need to work on the finish of the chamfers of the holes though, but not critical.

Here is one of them partially freed from the larger plate:

And yes, I did all the cutting with that hacksaw.

And here it is finished.

I radiused the cornered on my 8" bench grinder and I made the surface pretty darn flat by taking a bastard file and draw filing across the entire surface until I had it level. Then I moved to a smooth mill file and draw filed, then I used a sharpening stone on it. I did this to both of them on the sides where they mate with the bearing flanges. I did the same to the non-mating sides, but not to such great detail. I just made those sides look more decent. Then I sprayed them off with brake cleaner, cleaned them up with soap and water, then rubbed them down with 3-in-1 oil.

And here is the finished product mated up with the bearing flanges.

 

[dave1701]

Looking good. You sound like you sure know what your doing.

 

[JHen]

Thanks, I try lol.

 

[landuse]

Nice work. A hacksaw is sometimes better at getting straight lines then a cutting wheel on a grinder or a chopsaw.