GoKart Senior Project Advice

[kitzimoose]

Hi, a friend and I are planning to build a go-kart for a senior engineering project. We will design and weld the frame (we know people with welding experience to help us learn). We are planning to use a Predator 420cc 13hp engine and will most likely end up with something like a yard kart frame design. We are on a tight-ish budget tho.

here is a link to our current parts list:
Build Sheet Google Sheet

I just had a few questions:
- Would all these parts work together?
- What wheels would be recommended and would work with this setup?
- What other parts am I missing that's a requirement?
- What material should we use to make the frame (we were thinking steel)?

 

[panchothedog]

With a 420 engine, you are going to need a 40 series torque converter. I think your
estimate of $70 is for a 30 series. It is not strong enough to use with a 420. Also,
most 30's are for a 3/4" shaft. The 420 has a 1" shaft..In general, the 40 cost about twice as much as a 30. Still, A torque converter is the way to go. They function as an automatic transmission, and work great.

 

[kitzimoose]

With a 420 engine, you are going to need a 40 series torque converter. I think your
estimate of $70 is for a 30 series. It is not strong enough to use with a 420. Also,
most 30's are for a 3/4" shaft. The 420 has a 1" shaft..In general, the 40 cost about twice as much as a 30. Still, A torque converter is the way to go. They function as an automatic transmission, and work great.

on the list everything is a hyperlink not just an estimate and the torque converter I linked has a 1" bore and claims to be rated for 8-13hp engines.

 

[Master Hack]

You want to use steel for sure. 1 inch x .120 tubing is the best choice. I prefer round tubing, but then ya need a bender. A lot of the DIYers here use square tubing cuz ya can cut and weld angles easier. Either one works well, just a matter of preference and equipment.
Where are you buying enough steel for $25? A handful of rems cost more than $25 here.
Most of the DIYers use water pipe with good luck, just avoid the galvanized stuff.
Welding galvanized steel releases toxic fumes that are best avoided.

l did not see on yourr list:
wheels
chain
hubs
sprocket
spindles
brakes
steering wheel
paint & primer

 

[kitzimoose]

You want to use steel for sure. 1 inch x .120 tubing is the best choice. I prefer round tubing, but then ya need a bender. A lot of the DIYers here use square tubing cuz ya can cut and weld angles easier. Either one works well, just a matter of preference and equipment.
Where are you buying enough steel for $25? A handful of rems cost more than $25 here.
Most of the DIYers use water pipe with good luck, just avoid the galvanized stuff.
Welding galvanized steel releases toxic fumes that are best avoided.

l did not see on yourr list:
wheels
chain
hubs
sprocket
spindles
brakes
steering wheel
paint & primer

sorry the "weld metal" is weld wire It was just mislabeled but its fixed now thanks

The wheels/tires are what I'm looking for advice on
The chain, hub, sprocket and brake is in the live rear axle kit
The steering wheel and the spindle is in the steering rod kit
paint and primer I'm planing on just using Rustoleum in black from home depot (I've already got the color i just need the primer)

thanks for the advice on the steel I'm planning on going to scrap yard.

 

[Master Hack]

Sounds like ya got it covered. I'm not familar with any "kits". Fact is im not familar with new parts at all.
Fabrication shops are my favorite sources for steel. Rems are $0.25 - $1 per pound
and an occasional treasure.
The weld metal? Weld wire? Are you planning on TIG or MIG welding? Just curious.

 

[bob58o]

To add suspension without adding suspension, large, low pressure, balloon type tires in the rear will give your ride some cushion. Maybe something like 19” rear tires? Then find a wheel to fit the tires you want. The tire size will need to match the gear ratio so let us know what pitch and tooth count on rear sprocket comes with the axle kit.

With 19” rear tires, you could probably do a 5.4 : 1 sprocket ratio if using a 40 series Torque converter and 420cc engine.

 

[bob58o]

The axle kit looks like it comes with a 58T #530 sprocket and chain. The torque converter comes with #41. One is 1/2” pitch. One is 5/8”. They are not compatible.

You would need to swap out the 10T #41 for a #530 sprocket. The TC kit linked uses a 5/8” jackshaft so the sprocket would need a 5/8” bore.

"C" TYPE SPROCKET, 10 TOOTH, #50/530 CHAIN, 5/8" BORE, 3/16" KEYWAY, NO SET SCREW, 10 TOOTH

OMB Warehouse - Go Kart Parts and Mini Bike Parts. OEM and Aftermarket supplier of Outdoor Power Equipment Parts, Arborist and Landscape Supplies.

www.ombwarehouse.com

That torque converter kit may not hold up to the HP and TQ of the 420cc engine. I would only suggest that kit for the smallest 1” crankshaft engines, like a 301cc.

 

[bob58o]

I don’t have experience using 40 series TAV with the self mounted shafts using the backplate. I believe the cheaper options are like this one posted here. You’ll notice 40 series TAV usually come with 3/4” jackshaft, larger than the 5/8” ones that come on 30 series.

Again you would need to swap out the 1/2” pitch sprocket, but for this kit you’d need a 3/4” bore sprocket.

 

[bob58o]

Since your building your own…
You could price out the parts to mount the jackshaft to the frame.

Tou can buy 40 series driver, driven, and belt.
Some 3/4” pillow block bearings.
A 3/4” keyed jackshaft.
A 3/4” bore #530 10T sprocket.
Some 3/4” lock collars.

Should be able to get everything for under $200

 

[kitzimoose]

Sounds like ya got it covered. I'm not familar with any "kits". Fact is im not familar with new parts at all.
Fabrication shops are my favorite sources for steel. Rems are $0.25 - $1 per pound
and an occasional treasure.
The weld metal? Weld wire? Are you planning on TIG or MIG welding? Just curious.

im planning on doing MIG welding but without gas so from what I've read online I need welding wire then

 

[Sparkwizard]

You could save a pile of money by starting out with a smaller engine.

 

[kitzimoose]

You could save a pile of money by starting out with a smaller engine.

yea i wanted to just go 212cc but the friend I'm doing this with is insisting we should just use a 420cc engine

 

[Functional Artist]

yea i wanted to just go 212cc but the friend I'm doing this with is insisting we should just use a 420cc engine

Kool idea

Do you'all have a budget for this project?
...'cause you'all are gonna need A LOT more stuff
...& even (the cost of) all of the little stuff (nuts, bolts, washers etc.) adds up quickly

As said before...if you'all can re-evaluate the "plan"
...a Predator 212 (6.5HP) & accessories
...can be obtained for ~50% of the cost of a 420 & accessories
...& will propel (zip around) a kart quite nicely, with a full size human

&/also,

As said before...its best to make sure everything is compatible like the chain & sprockets (pitch) & even gear ratio (including tire size)
...& it's best (& cheaper) to do ALL of this...before purchasing...anything

 

[Sparkwizard]

^^^^AMEN^^^^
Honestly, it might make sense to find a used frame and go from there.
Building a kart on any kind of a time crunch is very, and I mean VERY expensive.
If you have time to let it sit while you accumulate used parts, then the price goes down, but the time goes up.

 

[bob58o]

im planning on doing MIG welding but without gas so from what I've read online I need welding wire then

Flux-core?

 

[Sparkwizard]

gasless welding is NOT THE WAY to weld any type of tubing. Learning how to weld with flux core wire is to be done on solid steel SCRAP metal, not a frame that you intend to keep.

I saw that fact the other day, but I forgot to add my two cents worth of learning from my failures.
Flux core wire is hot, burns holes, does not fill those holes well, and it makes dirty, ugly welds.

 

[kitzimoose]

Kool idea

Do you'all have a budget for this project?
...'cause you'all are gonna need A LOT more stuff
...& even (the cost of) all of the little stuff (nuts, bolts, washers etc.) adds up quickly

As said before...if you'all can re-evaluate the "plan"
...a Predator 212 (6.5HP) & accessories
...can be obtained for ~50% of the cost of a 420 & accessories
...& will propel (zip around) a kart quite nicely, with a full size human

&/also,

As said before...its best to make sure everything is compatible like the chain & sprockets (pitch) & even gear ratio (including tire size)
...& it's best (& cheaper) to do ALL of this...before purchasing...anything

yea ik 212cc is going to be way cheaper. the budget is as low as possible. I'm going to talk to him again today and see if i can convince him to go 212cc even if we spend a bit more to build the engine. What other stuff will I need? and yea i need to find tires/wheels but I'm not really sure on what to go with at all. The nuts, bolts and washers I'm estimating around $100-$150 for (does that seem right?)

 

[kitzimoose]

Flux-core?

yes

 

[Sparkwizard]

Flux core NO....see post #17.