Newbie just bought a Kart with potential #2

[perceptionist]

I've seen that, it's perfect but a tad steep. I saved pics of it to study. I would definately be interested in those plans if you are offering. I also wanted to incorporate a differential so I would not have steering issues on hard ground. I liked this as a starting point:

http://www.westgarage.co.uk/chaindrive/chaindrive1.html

But it comes out to about a grand.

 

[modelengineer]

Sorry, not offering the plans. I only have them in hard copy, and I like to support small business.

If you've ever driven one of the buggies from http://edge.au.com you will notice that they turn just fine without a diff, even on sealed surfaces. Also, since you're buggy will be longer, with the tandem layout, but not any wider than a normal buggy the need for a differential will be even less.
Trust me, you will not need a diff. They make it so you can only do 1 wheel burnouts and they get bogged much easier than straight axle (unless you get an LSD which is even more expensive).

 

[perceptionist]

The reason I was considering a diff, When I first brought the kart home, it was in semi drivable condition with solid live axle. Turning the wheels all the way in either direction while moving forward did absolutely nothing. The kart would just push straight forward on the street grinding the front tires. I tried a little experiment by detaching one of the wheel hubs from the axle allowing it to freewheel which resulted in functional turning. This experience was why I wanted to incorporate either a diff or I was considering a locking hub at one wheel so I could disconnect it as needed for street and then engage it for full live axle in the dirt.

I also had a thought of cutting the axle in half right in the center between the sprocket & brake rotor, and weld two flanges on the ends that can be bolted together or disconnected.

0---||---0

Or if it would be possible to manage the connect/disconnect (for live to one wheel) from the driver's seat that would be the ultimate.

Doesn't a full live axle undergo stress and possible damage from turning on the asphalt if the tires are gripping effectively? Somethings got to give right?

I don't know for sure, just seems logical.

 

[jr dragster T]

The reason I was considering a diff, When I first brought the kart home, it was in semi drivable condition with solid live axle. Turning the wheels all the way in either direction while moving forward did absolutely nothing. The kart would just push straight forward on the street grinding the front tires. I tried a little experiment by detaching one of the wheel hubs from the axle allowing it to freewheel which resulted in functional turning. This experience was why I wanted to incorporate either a diff or I was considering a locking hub at one wheel so I could disconnect it as needed for street and then engage it for full live axle in the dirt.

I also had a thought of cutting the axle in half right in the center between the sprocket & brake rotor, and weld two flanges on the ends that can be bolted together or disconnected.

0---||---0

Or if it would be possible to manage the connect/disconnect (for live to one wheel) from the driver's seat that would be the ultimate.

Doesn't a full live axle undergo stress and possible damage from turning on the asphalt if the tires are gripping effectively? Somethings got to give right?

I don't know for sure, just seems logical.

It doesnt hurt a thing. Tires just break loose on one side. Pretty hard to damage a solid 1 inch or 1 1/4 peice of steel.

 

[modelengineer]

Because you've made the kart longer the radius which the rear tyres follow in a turn will be more similar, if that makes sense, so it should turn alright.

I advise make it live axle. Then IF you are not happy with the turning (unlikely) then you can put a freewheeling hub on it or something else. Just remember that 2 wheel drive is more fun than 1 wheel drive (I just know I'm going to get flamed by somebody with a 1 wheel drive kart for that. Bring it on )

 

[perceptionist]

I just measured the frame.

Length = Just under 10 ft

Width (@ widest point) = 4 ft

And while I'm posting, I wanted to get some advise on angles and positioning on bracing for the extended front. I am a bit worried that as long as it is, it might bend. I also considered welding an extra square tube along the full length of the bottom for added support but I am no structural engineer

 

[modelengineer]

Easiest way is to look at it side on and make the rectangular parts in to a series of triangles, by welding in square (or round) tubes. Called triangulating, it will make it very strong.

 

[perceptionist]

That is what I plan to do with square tube, but I was unsure if specific positioning of the triangles was crucial to the integrity.

BTW modelengineer, do you work at "Edge"? I was planning to put my fuel tank under the rear seat since it will be lifted anyways and that will provide the perfect location for it. Then I realized that I would need to include a fuel pump since the motor I have is typically gravity fed. My research led me to the FAQ here:

http://www.git.com.au/~theedge/faqs.htm

Question: "What type of Fuel pump should I use on my Motorcycle powered buggy?"

This is what I drew as my interpretation of method 3:

 

[modelengineer]

No, I don't work at Edge I am just active on their forums and I am building one of their buggies. No other affiliation.

That diagram is exactly what they mean. If you use an electric fuel pump that diagram is perfect, if you are using a diaphragm pump then you need an extra connection between the intake manifold of your engine and the fuel pump. The diaphragm pump doesn't need electricity to work and is, usually, cheaper. Unless you can get an electric fuel pump from wreckers or somewhere cheap.

 

[perceptionist]

Yeah I noticed the mention of a diaphragm pump but I didn't quite grasp the concept of how they function. I will do some more research on them.

 

[jr dragster T]

The Diapragm pumps use pulses from the intake or the block to make a rubber flapper move up and down and pumping fuel.

 

[perceptionist]

More Pix...

The operating room:

Overhead View, Hey it looks like a coffin, hmmm.

Another angle

These were taken last night. It has been getting cold and my heater has trouble keeping up in my un-insulated garage. I think I may begin shopping around for the main fuel tank now. The maximum space I have to work with is 30" x 19" x 6". (14.81 US gal) I am shooting for around 12 gal though if I can find something 30" x 15" x 6".

The main tank will sit beneath the rear seat so I plan to mount some kind of skid plate on the frame under the tank. The rear seat will not be supported by the tank, I will weld in supports to "Cage" it in.

These seats even have magazine holders on the backs in case my passenger feels like reading while riding around in the coffin shaped kart

 

[perceptionist]

That diagram is exactly what they mean. If you use an electric fuel pump that diagram is perfect, if you are using a diaphragm pump then you need an extra connection between the intake manifold of your engine and the fuel pump. The diaphragm pump doesn't need electricity to work and is, usually, cheaper. Unless you can get an electric fuel pump from wreckers or somewhere cheap.

I tried searching for diaphragm fuel pumps and mostly got mechanical diaphragm pumps and much larger than I thought pumps. Can you recommend one to look at, or key words I can use to fine the right one for this application?

 

[kibble]

Overhead View, Hey it looks like a coffin, hmmm.

just hope it's safe enough in the end NOT to become one!

Looking good!

 

[perceptionist]

If you wanted to put CV joints in the rear consider copying/buying this design:
http://edge.au.com/product_pircv.htm

I have the plans and they are very detailed, but you would need a machine shop to build it (cheaply).

I went to check out the price list for the plans on that design here:

http://edge.au.com/store/category1_1.htm

And there appears to be plans for another rear suspension (in that price list) that I did not see pictures of. It was titled

"Plan- Double A arm - Comprehensive plans to build the Double "A" arm rear suspension"

I was curious to see the alternate design but couldn't find examples of it, only the PIRCV Rear Susp. Am I blind

 

[perceptionist]

Pix

I just welded in the riser frame for the rear seat last night. This will also serve to house the main fuel tank and possibly a small tool storage space.

On another note...

I was brainstorming about the routing of my shift linkage and thought it would be cool to allow an option for the passenger to handle the shifting. Not exclusively though, shifting would be accessible to driver and passenger. If the linkage is passing by the passenger seat on the way to the front, well I figure what the hell right? I would figure out a way to disconnect it as needed.

I was also contemplating other cool fun functions that the passenger could optionally serve just to make the riding experience a bit more interactive.

Any "think outside the box" ideas welcome.

 

[modelengineer]

Seriously, DON'T let the passenger do the shifting. Unless you give the passenger the clutch and the throttle they won't be able to shift properly.
You're just as likely to get some idiot in the back (who you forget to tell about the shifter) to pull you down into 2nd when you're redlining in 3rd, and screw up the engine from overreving.
You could have the passenger control the headlights, the horn (musical of course haha), maybe the ignition if you really wanted to, non-critical stuff like that.

Here are pics of the suspension from edge:
PIRCV Rear

Double A Arm Rear

Standard single A Arm Rear

 

[perceptionist]

Oh I know the potential for idiots in the passenger seat which is why I would incorporate a lockout. The shifter would be for someone I trust to coordinate our efforts.