Building a kart

[Hardyx]

Hi guys, I'm not sure if this is the right place to post this, hope it is. I've been thinking a lot lately on getting involved on the karting world, just for fun, not willing to compete (yet ). There's a karting track pretty close where I'm living now so when I have some free time I use to get some laps. Unfortunately it is quite expensive (30€, about $40 for just 8 minutes with a competition kart) so yeah, I don't have fun for too much time.

So I've been thinking on buying a kart, but uh, they're quite expensive too. So another alternative is to build a kart by myself. I have an old Aprilia RS50, which is not legally able to be used on the road, so I'm thinking on using its engine, radiator, etc. and sell the rest of the parts. It's just a 50cc engine with around 6hp which isn't too much, but it can be greatly improved with little money, ok, it will not be too powerful, but as I said before, I just wanna have some fun. Regarding the chassis, my cousin is welder so I can ask him to help me out with it. And for the rest of the parts, well, I'll have to invest some money.

So what do you think, it's a feasible project or I'm just crazy?

 

[ECGadget]

It's completely feasible, but make sure you take every precaution regarding safety. When it comes to chassis design, you may want to try a modelling software first, that way you can make sure all the stresses will be okay. In terms of welding, just make sure they are strong. Another bit of advice, not sure if it matters with karts though, is triangulation. Make sure all the components of the chassis are properly triangulated.
Make sure also that you do proper research and are willing to look around for a while to find a cheap deal ^^

Best of luck and post some pictures here if you are going to do it!

 

[v4orce]

an old gsxr/cbr 600 engine could be more fun when you get used to the kart with the 50cc

 

[jjsahagun]

i always

Hi guys, I'm not sure if this is the right place to post this, hope it is.

I always wondered why there is not a karting thread in GTP...

 

[Lizard]

i always

I always wondered why there is not a karting thread in GTP...

There is.

https://www.gtplanet.net/forum/threads/karting-thread.126005/page-49#post-9615498

 

[Hardyx]

It's completely feasible, but make sure you take every precaution regarding safety. When it comes to chassis design, you may want to try a modelling software first, that way you can make sure all the stresses will be okay. In terms of welding, just make sure they are strong. Another bit of advice, not sure if it matters with karts though, is triangulation. Make sure all the components of the chassis are properly triangulated.
Make sure also that you do proper research and are willing to look around for a while to find a cheap deal ^^

Best of luck and post some pictures here if you are going to do it!

Wow! Thank you! That makes me really happy. Certainly this is not something that I'm gonna do in a short period of time since I'm not having too much free time lately so my plan is to spend quite a while gathering information, working on the design, etc. But I would like to have it ready for the summer. Tomorrow I'm gonna start by disassembling and overhauling the parts of the aprilia I plan to use and selling the rest, hopefully I'll get some money to invest on other parts. I'll keep you updated!

an old gsxr/cbr 600 engine could be more fun when you get used to the kart with the 50cc

That sounds crazy lol, but would be awesome actually.

 

[Bopop4]

50cc would be way too slow unless you're 5 years old.

A 600 would be impractical as well.


A Honda GX200 is what you would want . About 8hp after you take off the governor and put a pipe on it.
A 125cc motocross bike engine would be better, but it would be so fast that I would get a professionally made chassis.

Although it's all rather meaningless when it'll cost you more to buy the necessary parts than it would to actually buy a used kart.

Hubs, tires, rims, axles, seat, braking system,chain, gears, clutch, plastic bodywork.

If you want to build a kart to rip around a field in, then do it yourself, but if you want to take it to a track, definitely get a premade one. I don't even think they'd allow you on the track in something that you put together in a shop.

 

[phillgt2002]

50cc would be way too slow unless you're 5 years old.

A 600 would be impractical as well.

Psshh. Get out of here.

OP, feel free to do what you want. Strap a tank/jet engine on that thing and take off towards the stars.

 

[lbsf1]

Karts are far more complex than you think, I don't have time to give a full explanation now however I will later.

 

[Bopop4]

Karts are far more complex than you think, I don't have time to give a full explanation now however I will later.

Yeah, a 2mm difference in the tubing thickness will make it handle extremely bad.

And that's before you get into trying out different combinations of metals.

 

[Grayfox]

Try finding an old cart with a dead engine and use the chassis.

I would say go for an electric.
About 6 3000Farad Ultra caps wired up in series will easily give you 12-13v and you will have 500farads of energy storage which is a fair amount.
So you will have a huge amount of power, a lightweight body since batteries can be heavy unlike capacitors which are much lighter, fast at recharging

 

[lbsf1]

Right, here is the full explanation.

Kart chassis are really difficult to make, as said above when a company makes a chassis they spend lots of time/money on computer modelling of the materials and design. Even then there can be problems (Intrepid Storms from 2012 had a really bad tendency to crack and snap around the engine joint if a vibrating engine (TKM) were mounted).

The materials used are also very precise, tonykart for example are rumoured (seen it mentioned lots of time but never any complete proof) use a slightly different material at the front of their chassis then at the back.). Also a couple of mm difference in tube makes a big difference, 28mm is considered very flexible, 32mm is stiff as buggery (Tonykart vs TWS/octane for anyone in the know). Also kart chassis are made from tubular steel not angled/square which makes the production and sourcing more of a pain.

Kart chassis have to cope with lots of physics that are unique to karting. The main part of this being the jacking effect. Because a kart has no differential the inside rear wheel actually needs to lift/slip round corners otherwise you will have horrible understeer. This is done using lots of complex geometry at the front of the chassis, ackerman steering means the inside front wheel turns more than the outside, the stub axles are also angles so that the inside wheel actually lifts the kart up, thus pivoting the kart on the inside front and outside rear tyres and allowing this inside rear to lift.

The above is possible to do yourself, however it is a precise balance, when racing karts you will be making tiny adjustments (moving wheels in or out 1cm for example is drastic) or adjusting camber and caster by a few degrees. If you have it wrong by those couple of degrees the kart will handle like a dog.

By no means am I saying that it’s impossible to do it by yourself. Back in the late 80’s when my dad raced karts one of his friends was a key technician/metalworker at the Tyyrell formula one factory, he created his own chassis from scratch, however he was very skilled at what he was doing and had huge experience with lathes and welding.

My advice would be to by yourself a cheap old chassis, even something 10 years plus old will be far better than anything you could make by hand, these will also be dirt cheap. If you do use your engine (Which sadly will be pretty slow) simply getting that to fit on the chassis will be more than enough work.

Good luck, hope you have lots of fun with your project whatever you decide to do.

 

[ECGadget]

Wow! Thank you! That makes me really happy. Certainly this is not something that I'm gonna do in a short period of time since I'm not having too much free time lately so my plan is to spend quite a while gathering information, working on the design, etc. But I would like to have it ready for the summer. Tomorrow I'm gonna start by disassembling and overhauling the parts of the aprilia I plan to use and selling the rest, hopefully I'll get some money to invest on other parts. I'll keep you updated!



That sounds crazy lol, but would be awesome actually.

You're welcome. And as @lbsf1 has mentioned, it is a difficult job! I was part of a team designing a formula racecar and it is very difficult to make sure that the chassis can handle the different loads. Now that being said, I think there are plenty of people here that could advise you through the different steps. I for one would be happy to help you out! I believe that if you use tubing with a 1.6mm wall thickness (a 25mm tube diameter), it should be adequate for your engine (which isn't the best unfortunately), but remember that it is a balancing act between weight and safety!

 

[Hardyx]

Thank you guys for your advise and for keeping my feet on the ground. To be honest, at this moment I can't afford even a secondhand kart, hence my crazy idea of building one by myself. I thought it wouldn't be easy, but I didn't expect that it would be that complex either, so probably is time to think about it. Being realistic, spending money and time on something that is unlikely to work properly is kinda stupid, isn't it? And probably as @Bopop4 said, the track owners wouldn't allow me to use a handmade kart.

I'm still not giving up the project, but I'm gonna take some time to think about it before doing something stupid.

Many thanks to ALL of you again.

 

[Tom]

I'm a previous Kart owner, I had a Wright chassis with a TKM Rotax 100cc engine that went like the clappers after a bit of fettling. I paid £350 for that in working condition, which isn't much more (if at all) than building your own would cost. I think with my weight of 53kg I managed to top out at around 70mph.

The main problem (as a fellow RS50 owner) that I can see with using an engine from a motorcycle aside from the unreliability problems is that they are designed to rev a lot higher and thrashing it when cold may do serious damage to the engine. Something to think about.

 

[Hardyx]

I'm a previous Kart owner, I had a Wright chassis with a TKM Rotax 100cc engine that went like the clappers after a bit of fettling. I paid £350 for that in working condition, which isn't much more (if at all) than building your own would cost. I think with my weight of 53kg I managed to top out at around 70mph.

The main problem (as a fellow RS50 owner) that I can see with using an engine from a motorcycle aside from the unreliability problems is that they are designed to rev a lot higher and thrashing it when cold may do serious damage to the engine. Something to think about.

Wow, 350 pounds sounds pretty cheap to me. The cheapest second hand kart I found so far was around 1500€, which it's out of my budget.

 

[lbsf1]

Wow, 350 pounds sounds pretty cheap to me. The cheapest second hand kart I found so far was around 1500€, which it's out of my budget.

That is far, far too much. The kart in my profile pic was £500 for the chassis (2 years old at the time) and £1000 for the engine (A proven 2009 engine), so the whole kart was only just over what you saw that cheapest one for. If that is what karts cost in Spain I'm incredibly surprised, in the UK you can pick up an old rolling chassis (Everything but the engine) for £150.

For example a very quick search brought me these in the UK:

Cheap Prokart Rolling Chassis
Zip Kart Prokart rolling chassis.
Tillet Seat (L), Mojo Slicks, Q/R axle bearing clamps, Ackerman steering.
Centre fuel tank inc fuel pipes, throttle cables, chains & sprockets.
Axle runs true, brake is operational.
Can email pics.
Priced to sell at £225.

Or this one is only £200 (I'm surprised at the price of this, it looks in really nice condition)

 

[ECGadget]

That kart is in really good nick! If I had time to race, I would have bought that!

 

[Hardyx]

Yeah, sadly that's the situation here

I'll be in UK in july for a week (job stuff) so it could be a good idea to take the trailer with me and look for a bargain like that. I'm gonna try to sell the RS50 parts in order to gather some money. So, what kind of kart (engine, chassis, etc.) should I look for?

Thank you guys!

 

[Hardyx]

Hey guys, I just found this: http://www.milanuncios.com/venta-de-karts/kart-125-prd-gilkart-127054270.htm

Someone knows about the Gilkart brand? And what about the PRD engine? I've never heard of them :S

What do you think?

 

[lbsf1]

Never heard of Gilkart before, however thats not necessarily a bad thing, a friend of mine won championships on a chassis brand that no one had ever heard of. Their website its here however http://gilkarts.com.br/

Engine looks like a PRD fireball engine http://en.wikipedia.org/wiki/PRD_Fireball , these seem reasonably popular engines from what the internet is telling me, I have never seen them in the UK, however from the amount of stuff online you shouldn't find yourself stuck for resources. It looks really nice however I will just warn you, with a two stroke engine like that even if you are running it gentle and slightly rich you will be looking at a top end (Piston and rings) rebuild every 10 or so hours, if you are mechanically minded you can do it yourself however it will need doing.

 

[Hardyx]

Thank you @lbsf1! Although I'm not professional, I'm quite experienced with 2t engines, so I don't think I'm gonna have problems with it, anyway, thank you for your advice!

By the way, I found another candidate which seems to be a bargain, but I'll need some advice once again. It's a 2008's Tony EVXX with a IAME x30, the seller wanted 1800€ (~ 1500 pounds) for it, but after talking a bit he has dropped the price to 1200€ (~ 980 pounds), he needs the money urgently to pay the mortgage of his house. Here you have some photos:

What do you think guys? Looks like a good opportunity.

 

[lbsf1]

Thank you @lbsf1! Although I'm not professional, I'm quite experienced with 2t engines, so I don't think I'm gonna have problems with it, anyway, thank you for your advice!

By the way, I found another candidate which seems to be a bargain, but I'll need some advice once again. It's a 2008's Tony EVXX with a IAME x30, the seller wanted 1800€ (~ 1500 pounds) for it, but after talking a bit he has dropped the price to 1200€ (~ 980 pounds), he needs the money urgently to pay the mortgage of his house. Here you have some photos:

What do you think guys? Looks like a good opportunity.

Iame x30 engines are much better known (in the UK anyway) and I think much more suitable for your use (longer times between rebuilds.)

The EVXX is a really nice chassis, I know a few people who still race them. This one looks in nice condition however with tonykarts because they are more flexible chassis you need to check that there are no bends and that it is completely straight (shouldn't be an issue considering it looks like he is running the original plastics and stickers), also spares are more expensive for tonykarts (You can find some items that are cheaper copies of parts, however the official OTK spares cost an arm and a leg.)

Overall however for that price it looks really nice, is he offering any spares/parts/tools with it for that price?

 

[ECGadget]

It doesn't look too shabby at all. Though I have to say that seat (if it is the OMP one I am thinking of) needs some padding to be comfortable. Chassis looks good, bodywork probably just needs a respray. Chain looks decently looked after and I can't see anything problematic with the engine. May want to pop new tyres on to it, and always try and gets tools with it, like @lbsf1 said. Though I think most of the tools should be standard, no?

 

[Hardyx]

Iame x30 engines are much better known (in the UK anyway) and I think much more suitable for your use (longer times between rebuilds.)

The EVXX is a really nice chassis, I know a few people who still race them. This one looks in nice condition however with tonykarts because they are more flexible chassis you need to check that there are no bends and that it is completely straight (shouldn't be an issue considering it looks like he is running the original plastics and stickers), also spares are more expensive for tonykarts (You can find some items that are cheaper copies of parts, however the official OTK spares cost an arm and a leg.)

Overall however for that price it looks really nice, is he offering any spares/parts/tools with it for that price?

Umm, I think only the kart is included, anyway I will ask. Probably I should ask if all of its parts are OTK as well. He needs the money for tomorrow, so I don't have too much time to decide...I'm quite confused right now

 

[Hardyx]

It doesn't look too shabby at all. Though I have to say that seat (if it is the OMP one I am thinking of) needs some padding to be comfortable. Chassis looks good, bodywork probably just needs a respray. Chain looks decently looked after and I can't see anything problematic with the engine. May want to pop new tyres on to it, and always try and gets tools with it, like @lbsf1 said. Though I think most of the tools should be standard, no?

The aesthetics aren't a problem at all, I can get a respray for free. My biggest concern is if the chassis is bent and I'm unable to identify the issue since I have near zero experience with kart chassis. Also I'm concerned about its age, isn't too much 6 years for a kart?

 

[ECGadget]

Some more details


The aesthetics aren't a problem at all, I can get a respray for free. My biggest concern is if the chassis is bent and I'm unable to identify the issue since I have near zero experience with kart chassis. Also I'm concerned abouts its age, isn't too much 6 years for a kart?

From the pictures all the welds look solid, the chassis work all looks free from buckles or anything. I can't see any visible signs of overstressing the chassis. As for the age, I'm afraid I wouldn't know too much about that!

 

[Bopop4]

Bodywork isn't painted, it's coloured plastic with decals.

The PRD is a budget engine, but from what I read years ago it's a good engine.

6 years isn't too old either.

 

[Hardyx]

Bodywork isn't painted, it's coloured plastic with decals.

Ouch! I would have liked to paint it like a Mercedes F1, I really love that colour scheme

 

[Bopop4]

Ouch! I would have liked to paint it like a Mercedes F1, I really love that colour scheme

It would be cheaper and easier to get a set of decals made up by a graphic design shop.

It would look way better than if you tried to paint it.