Finished....

Well, it's finished. Mostly.

It goes, it stops, kids love it.

A few things need looking at:

1) After all the effort on the pedals, the brake pedal needs modifying. There's too much slop before anything really happens to the linkage to the master cylinder.

2) The front wheels are a little small - I think a small increase in diameter of about 2 inches or so would bring the kart more level, and perhaps make it less prone to understeer.

3) At some point some sides to the seat would be good - at the moment with the bench type seat, it feels as if you could slide out of it on the corners, which leads to hanging on to the steering wheel.

But all in all, it's doing the job! I'm pretty pleased.

One lesson learned though - I ended up changing the axle, hubs and sprocket carrier for commercially bought go-kart parts. The parts I made were OK, but making them was never ending, and the mounting method of bolting through the axle was never as good for adjustability than a proper keyway'd axle. I'd have never got the sprocket and disc brake lined up where they needed to be in relation to the engine and brake caliper respectively. And the parts were pretty cheap too.

So close....

In the last post I'd got to the stage where the kart was close to moving under it's own steam. The chain wasn't on though - I had to wait to get a decent chain tool sent from a kart bits supplier on ebay. So I sorted the chain out and  actually had it's maiden voyage, although I didn't write about it.

Because no pedals, I had a little go on it sort of reaching behind me to open the throttle on the engine directly . It moved along OK, but in the end it threw the chain off. Even though the axle is 30mm solid steel, the little engine still pulls hard enough to create whip in the axle (this is where the axle bends between the two supports and twangs back). So I needed a central bearing for the axle. I needed some steel plate, but I hadn't got any, so I cut up some large angle steel that I had stored safely at the bottom of the garden(!). I used this to make up a bearing mount and then welded that onto the frame. It was pretty simple - I bolted the bearing to the mount, put the axle on, and then welded it where it sat.

Here's some pics to show what I mean. The first shows the plate/bearing  in position:

This is after welding the plate to the chassis and slapping some more orange paint on:

And here it is with the sprocket and chain back on:

In that last picture, you can also see the brake line and caliper - yes, this means the pedals are complete!

It might be a bit hard to make out, but the pedals are in, and the linkages are complete. I probably should have taken a picture of the engine end to see how the throttle is arranged that end, so I'll try to remember that next time. The brakes lines are done. I got a load of brake line components from Car Builder Solutions, and made up the system with them. In the above pic, you can see the caliper is not fitted, but that's just two bolts. Then it's bleeding the system, and that's the kart done!

Leaps And Bounds....

Bored with pedals, I decided to paint the go-kart frame.

This is the 2nd incarnation. I had some John Deere yellow tractor paint, which I'd painted over some Bilt Hamber Electrox primer (good stuff, the Bilt Hamber). The yellow looked really pissy (forgive the expression), so a new plan was hatched. Given we have a Kubota mower, I thought maybe it would be good to get some of that paint and use it for the kart. So that's what I did.

There was much other work that went on after that, but for whatever reason, I didn't have my phone handy. So, I've nearly finished the pedals(!), panelled out the floor, and painted the bolt on components in deep Ferguson grey. I've gone with tractor enamel because I hoped it would be hard wearing. It's not proved the case so far, with it easily chipping and losing its finish fast. Hoping the paint will harden off over the next few weeks. Got some touching up to do even so.

So where are we now then? Well, we're here:

This is the little patch of grass outside the workshop. The two hop-ups are what the kart was sitting on as I built it up. You can see that it's pretty close to being done now. It would be a little further on if the cheap and very crappy chain tool I had from ebay had actually worked and I'd got the chain on. As it is, it's at a point where probably a good day with a following wind will see it done. The main obstacle is the brakes - I've got a couple of braided hoses to make, and some copper brake pipes to bend up and lay down. Then the throttle linkage and pedal stop to make (completing the pedal box finally).

Here are some other pics:

I feel a little ashamed - I've taken so long over this that the adjustable steering column (it adjusts for height) didn't need to be adjustable for the boy to use the kart. He's grown!

The fuel tank had to be split from the engine - the seat gets in the way. Looks good in that black against the orange. The back of the seat looks a bit 'home made' - I should have covered the whole back in red vinyl...

The rear track looks narrower than the front. It's not - it's exactly the same. Having said that, it doesn't 'look' quite right, so I'm thinking about how I can extend the axle. Perhaps a winter project.

One feature this view gives is the panelling underneath the sprocket and brakes. One most karts I've seen  this isn't bothered about (e.g. I spend lots of time on Cars and Cameras  Rather B Welding and Build Break Repeat channels on You Tube). I think that can't be good for a chain. I used to run motorcycles and getting dirt and grit in chains isn't good for them at all. So I've built a 45 deg angle fore and aft and a plate underneath to protect those components. I didn't weld those tubes on though - made up some brackets so that the tray can be removed to mess about with chain etc. if necessary.

Apologies for the background on the last few pics - the junk pile will be piled into a skip. Just waiting for some other rubbish to join it from next stages of house renos....

Weeks later, still doing pedals!

Well, I almost finished the brake pedal! The linkage to the master cylinder is done, and it works fine. It's got a little play in it, which I'll dial out by playing with the spacers.

In the above shot, you can see the mounting holes where the pedal assembly can be positioned in different places to suit different lengths of leg.

Probably the clearest view of the linkage.

I mounted the fuel tank too. The little tab with the socket headed screw  in it was the missing piece there.

Annoyingly I had to cut a brace to get the exhaust to fit. Silly mistake not having the engine sat there when I was building up that structure.

View of how it will all fit together...

Got to do the throttle pedal now!

It's getting on for a year since I started this thing - must pull finger out!

Go Kart pedals and other odds and sods

I've been wondering how to make the pedals and seat. The problem is that my kids are 9 and 6. My daughter is a tall 9. Very tall. So tall that there's no hope of her and the boy sharing the kart without some sort of adjustment in the pedals and/or seat. In previous photos there's been a sort of semi-completed seat (that frame sticking up with the diagonal brace):

Unfortunately, that seat was too far forward and too upright. Also the steering wheel ended up too low. Actually, might have been OK for the 6 year old lad, but no good for the daughter. So begins the challenge of making stuff adjustable.

So first is to relocate the seat further back and reclined some more. This will represent it's third incarnation. It's been even more upright before. I had also put the second diagonal brace in as an X shape behind the seat, so cutting this all off and having to reweld it all was a massive annoyance:

However, it's in. The completed X frame, two extra verticals behind it, a horizontal brace just below where the X crosses, and the seat frame is very sturdy. Because it's had to be moved back, it's meant that the petrol tank that usually sits on top of the engine can't live there anymore, and that's mean that I've had to make another bracket system for that that sits above where the X crosses. Perhaps a better pic of that next time. The bracket for the mounting of the brake caliper can also be seen. It goes from the floor of the kart to the horizontal brace.

The steering needed to be made adjustable too. It's not finished but here's the current state of it:

It's currently in the 'up' position. It can drop a couple of inches from here. Needs a good tidy up and a little extra bracing at the front, but other than that, it's done.

So, onto the pedals. This was a good deal more involved.

Needed to make a spindle onto which the pedals can rotate. I wanted to make a thread on each end so that I can put a lock nut on each end to hold the whole thing together.  The bar is 13mm, and so the nearest metric thread is M12 (12mm), so need to turn it down by 1mm. Onto the lathe:

Then need some bracketry made up. I also added the two tubes that the bracket is now sitting on:

The idea is that the pedals are in their own sub-assembly that bolts to the main chassis. There's an angle that locates the sub assembly onto the two tubes. Spindle is there in this shot, however, I might end up with R clips and not lock nuts. We'll see. Next make some pedals:

This is from the front, so throttle pedal is on the left. I used two different designs for the pedals, and i prefer the brake. So the throttle may get modified. The aluminium spacers can be seen too. The pedals fit nice and snug on them. Made the spacers on the lathe:

Then I realised that to actuate the brake, but have the whole thing adjustable still, that the brake master cylinder needs to be mounted where the pedals are. So that was next up:

This arrangement was a bit trial and error. The master cylinder is sitting above a piece of the same box section the chassis is made of, the two mounts are welded to that, and it is also welded to the pedal bracket. It wasn't strong enough like that, so the extra piece of bar was welded in alongside:

This is the assembly as of now. It's changed position to more like 'full tall person'. Just because it made it easier to work on. Those two holes in the foreground are 'full midget' spec.

Lots of little finishing up things to do on it (there's a linkage between brake pedal and cylinder to make, for example), but it's getting there. The pedal thing has taken probably 8 hours (including my usual 'putting stuff down and forgetting where' time wasted....)

Go go go-kart again.....

Small update. I wanted to do a couple of things - lots of the time with this, I have to leave with a problem still unsolved. I kind of have the thought about how I'll solve it, but not sure if it will work until I try. One example is how I am going to transfer drive to the wheels. In a normal go-kart that you'd buy, the axle has a keyway cut in it. A sort of square-ish channel. There's another cut in the wheel hub, and then when you go to assemble it all, you line up the two keyways and push a piece of rectangular bar called a key into the hole. This means that the axle and wheel will turn together.

If I had a mill, or a broaching machine, I could probably make the keyways, but I don't, so my plan is to drill and tap through the wheelhub and into the axle, and screw in a high-tensile steel machine screw into it. I'd done this, and got to the stage where I was about to screw in the screws, when I realised an error - I'd made the holes fractionally to close to each other and the screws interfered with each other. I was wondering if I could turn the screwheads down just enough for them to miss each other, and, luckily, I could!

Just a few odds and ends to address. Need to dress the welds holding the wheelbolts on and trim them to length.

I've also carried on with the other wheelhub. I had to weld up the hole I'd made down the middle because I need to have a flat surface for marking out the wheel bolt holes. So I welded it up and faced off the weld in the lathe. Then I did a bit of schoolboy geometry and marked out and drilled the holes.

Next I needed to drill a 30mm hole down the middle to match the axle:

Starting with a very small drill bit, and then moving up to the final size hole which is cut with a reamer.

Bit of a test fit.

And then weld on the wheel bolts and mock up:

I need to go through the same process with the drilling and tapping on this side too, and then that's the wheels done. All 4 of them!

A little more go kart? It's only waffer thin...

On with the steering. On the last update, we had the steering column (or whatever it's called in this context) done, and the front uprights and steering arms in. Now need some steering rods to go from column to uprights. These are made out of 12.5mm bar, but I needed to turn the ends down to get an 8mm thread on them to accept the rod-end bearings. Pic on left shows the turning, pic on right shows using the die for the thread - you can see the thread on left end of the rod already has the bearing on it.

And the completed rods connected to the steering arms and to the column

Now need to make a steering wheel boss. The technique I've used is the same for wheel hubs, sprocket carrier and now this. Cut out a rough circle the right size out of steel plate with a grinder. Take a piece of bar (in this case some of the same stuff as I've been using for the axles). Drill a 5mm hole in the centre of both and use the 5mm drill bit to align the two. Then weld them together, put the now joined part in the lathe, face it, turn it to a true circle, and then drill it for the column and wheel.

So it ends up like this. I've marked it for the steering wheel.

And drilled and tapped the holes to attach the wheel....

I drilled through the lower part of the boss and into the steering column to make sure the column turns when the wheel does. So this is how it looks now. I've missed an episode where I've got the left hand back wheel on. It's more or less the same drill as the steering wheel boss:

 Below is the process of making a wheel hub, or steering boss, or sprocket carrier. Cut out rough shape (I did mark out the diameter that I needed first - it's not all guesswork!)

Got to a rough circle.

Next step is to smooth it out a  bit - it has to go on the lathe and the less the tool gets smashed into by sharp edges, the better. Because it needs welding, it also gets a good sanding down so that the weld can penetrate.

Turning a piece of bar in the lathe. The diameter isn't crucial - I'm just trying to get the edges parallel and get rid of any corrosion. I get the ends square too, so when the other part is welded to it, it should run true (this rarely seems to happen 100%, so the whole lot gets faced again to ensure the face is perpendicular to the axis. I also put a chamfer on the ends too. The idea is that there's more for the weld to get into when attaching the circular plate.

The two pieces are welded together and spun up in the lathe.

Need to swap to a 4 jaw chuck - want this to run really true.

What it ends up like. Time will tell if this works out....

The part I'm making above isn't the sprocket carrier - it's the hub for the right hand rear wheel. Once that's done, it can sit on 4 wheels. I think that will feel kind of satisfying.

Since I've done all this, I've found somewhere in the UK that looks like they do bits for off-road karts, so I'll look at those next time to see if there's time I can save just buying bits. There are things that really don't need to be made. It's enjoyable to do though - apart from the odd ruined part, it's been fun doing everything from scratch...