Boy Scout kart build - dubbed "The Hot Rod"

[Bugzuki]

Made some progress

Here are some pictures of the progress, finally.

Building the shelf to mount the engine on:

Front suspension mostly complete. Still have some steering issues, but have made some progress.

Welded in the seat mounts:

Mounted the seats:

Mounted the engine. I have a 6x9x0.25 plate under the motor that is welded to the frame. I have some slots in it that it can be adjusted with.

Frame bracing at the front of the passenger compartment:

Close up. I got the MIG welder adjusted so it is working pretty nicely. The boys are more comfortable using that instead of the TIG.

View from the drivers seat.

*** Now comes the question. We have a lot to do before August. Part of my slowness is designing the rear suspension. I was thinking it would probably speed things up if I just used the swing arm from the quad for starters and then add the independant later.

Here is a mockup of the swing:

Here is the design I am working on. I have to rethink it because I did not look at the inside diameter of the wheel close enough and it will not fit.

So what do you think about the swing arm? If I put the wheels on inside out it will move the tires out almost as wide as the front tires. The issue might be getting the reverse drive to fit.

 

[B man]

that sure is turning out nice!

 

[redsox985]

I would go with the IRS as you have 2.5 months still and it will be far superior. It will have better drive, a better ride, and will be wider than the front.

 

[bighead]

Are you using the sled engine or the Yamaha 350 engine? What brand sled engine is that?

 

[Bugzuki]

I will see what I can get done on the rear suspension this weekend and try to make a descision from there.

I am now using an Arctic Cat 2 stroke 2 cylinder engine. The engine has a Suzuki badge on it. It is a 440cc engine.

 

[bighead]

I will see what I can get done on the rear suspension this weekend and try to make a descision from there.

I am now using an Arctic Cat 2 stroke 2 cylinder engine. The engine has a Suzuki badge on it. It is a 440cc engine.

Did you measure the center distance from the two clutches like we talk about a page or so ago? Will you make the bar? or just run with it? It would be nice to get the belt in the original location and not have to worry about slotting the engine mounts to mess with belts lining up.

Mount the drivin. Then hang the engine from racthet straps. Slide to mounting bar you made on. Then make your mounts from there while the engine is hangin.

this is a honda Odyysey but you get the picture. This moter is hangin in the pics as well. It was right before the engine mounts were made. If the bar slides freely on both shafts your engine and clutch are in the correct original location and lined up perfect. No belt wear problems. If you do this part right your clutches should work just like they did in the sled. You always know what belt you need as well.

 

[Bugzuki]

We could not get the drive clutch off. So we measured as best we could. I will be making the best measurements I can on the installation. I will be mounting the driven clutch instead of the engine like you did.

 

[redsox985]

Not to get too off topic here, but that's one nice shop you have there! I can see a big Miller machine in the back there as well as the Lincoln arc welder and a blasting cabinet.

 

[Bugzuki]

Not to get too off topic here, but that's one nice shop you have there! I can see a big Miller machine in the back there as well as the Lincoln arc welder and a blasting cabinet.

I borrowed the lincoln TIG welder from someone for this project. The Miller Dynasty is mine. The blasting cabinet I got from someone else that got it from Harbor Freight, I have not been able to get it to work at all.

Pretty much everything else in there is mine, including all the junk. I am still working on the shop, and there is a lot I could have done better. But that is a different story.

Thanks for the comment about it. It was a lot of work to build so it is nice when someone notices it. And it is a lot of work doing extra projects to pay for stuff in it.

 

[Bugzuki]

Some work done on the rearend.

Well, I finally have some pictures to show of what I have been working on.

I got the rear control arms tacked in place.

Here is a front/side view:

After getting the arms on I decided it was time to put on some gussets. The gussets will also act as mounting locations for the floor pan.

Here is a full bottom view of the kart.

After the gussets, I started working on the drive system. Engine, pullies, reverse drive and output hub are in works.

Here is the belt drive. The driven pully is not held in place, so it is slide down on the shaft a little. This makes it out of alignment with the drive pully.

Here is a look from the bottom. The output shaft on the reverse box started out as a hex sided shaft. I turned it. I will be mounting a hub to it with a sprocket on it.

I always seem to move forward with the build before I fully design everything on the computer. Here is a shot of the current issue I have. Looks like I have to reposition the engine yet again to make room for the brake disk, sprockets and chain. Back to the drawing board.

Hopefully I will be able to get some more work done this weekend. Got to get it painted and see if this engine runs. August is just around the corner.

 

[DCProductions]

I'm not sure if I'm right, but is the driven pulley on backward the way you have it assembled now?

 

[redsox985]

How did you calculate the length of your rear arms? I've always wondered how to properly find the length for uneven a-arms.

I tried talking to the one guy on here SAE Baja Captain, but couldn't get any info since it was all school property... This thing has crazy long travel and no bumpsteer. I waned to know how they did it.

 

[Bugzuki]

I'm not sure if I'm right, but is the driven pulley on backward the way you have it assembled now?

That is the way this pulley came off. So, that is the way it is going back on. If you are talking about the location: it was behind the engine on the sled. But, that doesn't really make a different, since it turns the same direction no matter where it is. Thanks for checking though.

How did you calculate the length of your rear arms? I've always wondered how to properly find the length for uneven a-arms.

I tried talking to the one guy on here SAE Baja Captain, but couldn't get any info since it was all school property... This thing has crazy long travel and no bumpsteer. I waned to know how they did it.

The object to get unequal arms to work is to set it up so that the wheel angles out at the bottom in the up position and in in the down position. This way the tires flex to have the most tread on the ground at all times.

In a situation where you are using tires that are not flat on the bottom (ie. motorcycle style) I don't see any real benefit to unequal arms. It looks like the arms on the baja in that picture are equal. If they are not equal the wheel in the up position would be angled. I guess the only benefit I can see would be to have the outside tire stick out farther in a turn.

My arms on the back are actually equal length. Just the 2x4 makes it look like I was planning them to be unequal.

Bump steer is a function of the steering arm being the same length as one of the A-arms and in the same plane as it. If the steering arm moves in a different arch than the A-arm it will cause the wheel to turn as the suspension flexes.

I used the front suspension off the quad, so it has unequal arms.

I think the easiest way to figure out arm length is to build some paper examples that are to scale and see how it acts, and how much the wheel angle changes.

I will try to come up with an example.

 

[redsox985]

I like the paper idea. If I were to ever do this, I would definitely mock them up with something prior. Maybe make cardboard models and try those out? Thanks for the info!

 

[r97]

looks great! makes me want an off road buggy even more! i would love to have a full suspension project to design, build, and test!

 

[Sentrek]

Kart looks awesome, great work. I am curious what size tubing you used for the frame work and how you bent it?

Sorry if it's been mentioned, it's getting late and I didn't read every post word for word.

 

[theo]

Looking good what are you using for rear axles?

 

[rabies]

considering its from scratch, nice work

 

[Bugzuki]

Thanks everyone.

Kart looks awesome, great work. I am curious what size tubing you used for the frame work and how you bent it?

Sorry if it's been mentioned, it's getting late and I didn't read every post word for word.

I am using 1 1/4 inch DOM tubing. I started out using 0.093 wall but switched to 0.065 to save some weight and cost. In the pictures the darker/dirtier tube is the 0.093 wall. The main structure is the thicker tube.

Looking good what are you using for rear axles?

The rear axles are over sized, but they won't break. They are out of a Mitsubishi Galant. I have to rework them to be the proper length. I probably should have gotten them from a metro or something, but these have the hubs and bearings combined and the same bolt pattern as my wheels. Larger bolts though. And the centering hub is smaller. But, those can be fixed.

 

[Sentrek]

Still curious how you are bending the tubing.