My Dirt Devil gokart build

[Nodroz]

Getting there, looking good!
Are you still going to redo the roll hoop?

Yes. It doesn't look good right now, lol.

 

[mysteryboy28]

i would make the roll hoop round on top. have seen too many videos on youtube of karts flipping on top of the driver. a pointy hoop would kill ya for sure!

 

[OzFab]

Just out of curiosity, what is the angle of the swingarm?

 

[Nodroz]

i would make the roll hoop round on top. have seen too many videos on youtube of karts flipping on top of the driver. a pointy hoop would kill ya for sure!

Yeap, this will become round once I get acces to a bender.

Just out of curiosity, what is the angle of the swingarm?

With or without weight on the gokart?


Btw, I went to the machine shop and together with a dude I managed to get my axle stepdown.
It's now 19mm in diameter on the ends, for the wheels. 20mm in diameter just on the place where my two bearings are attached and 25mm in the middle where the brake and sprocket will be placed.

I attached my 18" wheels on the axle and they fit perfectly! Now I need to drill a small hole through the axle to prevent my tires from sliding sideways.

My Honda Engine runs great. I'm going to see (probably buy too) another 5 speed motorcycle engine. Not sure if I'll dissambly the Honda mount and make a mount for the motorcycle engine, or I just stick with the Honda for now, and upgrade to the 5 speed in the future (in a couple of weeks).

Expect an photo update later today.

 

[landuse]

Yeap, this will become round once I get acces to a bender.



With or without weight on the gokart?


Btw, I went to the machine shop and together with a dude I managed to get my axle stepdown.
It's now 19mm in diameter on the ends, for the wheels. 20mm in diameter just on the place where my two bearings are attached and 25mm in the middle where the brake and sprocket will be placed.

I attached my 18" wheels on the axle and they fit perfectly! Now I need to drill a small hole through the axle to prevent my tires from sliding sideways.

My Honda Engine runs great. I'm going to see (probably buy too) another 5 speed motorcycle engine. Not sure if I'll dissambly the Honda mount and make a mount for the motorcycle engine, or I just stick with the Honda for now, and upgrade to the 5 speed in the future (in a couple of weeks).

Expect an photo update later today.

You have really done well on this build. Soon you will be riding it. I look forward to seeing what the wheels look like.

 

[OzFab]

Just out of curiosity, what is the angle of the swingarm?

With or without weight on the gokart?

Well, both but with weight more importantly. If it sits less than level, you may want to move the shock mounts...

 

[Nodroz]

You have really done well on this build. Soon you will be riding it. I look forward to seeing what the wheels look like.

Thanks! I will upload a picture once the weather is decent.

Well, both but with weight more importantly. If it sits less than level, you may want to move the shock mounts...

I'll try to check tomorrow. Sorry for the delay.

Small update today:
- Tack welded supports for fuel tank. Had a hard time getting the right position. It's a tight fit there.
- Getting the pedals positioned and welded in place.
- Tomorrow the axle will get it's keyway over the whole lenght.
- Tomorrow I'll try to make a new hub for my brake disc.

If everything goes as planned, I should be doing a first test drive this weekend.

Pictures tomorrow.

I've also decided how I'm going to organise with the 2 engines I have now. In the coming weeks, I will use the Honda Engine. Everything has been welded and lined up for that engine, so I'll use it for a bit of time. Also, because it will take a while before I get that 5-speed 200cc engine running.

Just got a mail back from the website I ordered my parts from:
€25 goods and €24.90 for shipping. Once I saw that, I annulated my order. Going to the shop this weekend... should be cheaper.


EDIT: I have a question regarding gear ratio and gearing.
I have a 13teeth sprocket on my clutch on the engine and I have a 38teeth sprocket on my axle. This clutch is a wet clutch with build in reduction of 1:2.

I'm having trouble to calculate my final ratio...
(Or: I have trouble?)
(Or: I'm having trouble calculating.. ? Lol my brain got messed up now.)

 

[exenos]

Just multiply the ratio from the clutch to axle by 2 to get the final ratio.

38/13=2.9

2.9*=5.8:1

5.8 is probably a bit too low for 18" tires, you may want something closer to 8:1-10:1

 

[Doc Sprocket]

You're making good progress- way to go! In the interest of durability, I would caution you against cross-drilling the axle to keep thing in place. Use locking collars instead.

 

[OzFab]

Just got a mail back from the website I ordered my parts from:
€25 goods and €24.90 for shipping. Once I saw that, I annulated my order. Going to the shop this weekend... should be cheaper.

I get really annoyed when I see this; it's even worse when the shipping costs more than the goods...

EDIT: I have a question regarding gear ratio and gearing.
I have a 13teeth sprocket on my clutch on the engine and I have a 38teeth sprocket on my axle. This clutch is a wet clutch with build in reduction of 1:2.

I'm having trouble to calculate my final ratio...
(Or: I have trouble?)
(Or: I'm having trouble calculating.. ? Lol my brain got messed up now.)

Just multiply the ratio from the clutch to axle by 2 to get the final ratio.

38/13=2.9

2.9*=5.8:1

5.8 is probably a bit too low for 18" tires, you may want something closer to 8:1-10:1

... so, something around 50 - 60 is good...

 

[landuse]

... so, something around 50 - 60 is good...

You are not going to have any fun without torque

 

[Nodroz]

Thanks for all the replies. I didn't know it was that easy to calculate, lol.

I decided to change my rear sprocket, but the rear sprocket is already very big. It's a really big, heavy chain. If I want to get a bigger sprocket, I need to get a smaller chain (probably #41) and then I can have a sprocket with more teeth on, but with the same size as the one I have now.

I've seen that industrial sprockets are really expensive here, so I was thinking to use a chain from a Skyteam Dax. This has 420 chain sprockets. The rear sprocket with 47 teeth (the max available) is €20. The chain is around €15. This could do.

However, the same chain size sprocket for the front is not available for my engine. In other words, the one you can buy for these motorcycles are different then sprockets with a keyway for on my engine.

I've seen a 420 is really close to a #41 size chain, so I've been thinking to buy a small industrial front sprocket.
Do you understand this? LOL

47 teeth as rear should be better than 38... maybe I should look a bit further for a bigger sprocket in that 420chain. Any ideas?

You're making good progress- way to go! In the interest of durability, I would caution you against cross-drilling the axle to keep thing in place. Use locking collars instead.

It's just a small hole at the end of my axle. Would it be that bad?

 

[Doc Sprocket]

No. I thought you were planning holes at midpoints of the axle, inboard of the wheels. You'll be fine with what you have in mind.

 

[Nodroz]

No. I thought you were planning holes at midpoints of the axle, inboard of the wheels. You'll be fine with what you have in mind.

Ah ok, thanks. The sprocket and disc brake will be hold in place the same way hubs for karts are locked - with a screw, that tightens the hub to to axle.

Btw: testing pictue upload on phone. Hope it works! Its a picture from todays work on the axle - cutting a keyway. Hopefully the rain will be gone tomorrow so I can show my tires and fuel tank mount.

 

[Nodroz]

Few pictures!

Attached sprocket today btw. It fits perfectly between my frame. My chain is too short though, I need a few more centimeters. Hopefully the local shop will have this in stock.
After a bit of measuring, I think the chain is #50 or 530. Quite big as you can see. If the local shop has it in stock tomorrow, I'll be driving that thing!

 

[Doc Sprocket]

Nice! I'll bet you're raring to go... Good luck!

 

[Nodroz]

New update!

Won't be long till I'll be driving this! I'm waiting for my clutch sprocket to get finished and then we're good to go for a first test!

I choosed to use another size of chain, the #40, with a 1/2" pitch. This will be lighter and a sprocket with the same size will have more teeth.

I didn't get a lot of choice for my rear sprocket, so I had to take the 45 teeth. I'll be able to get a 12 teeth sprocket for on my clutch, so my gear ratio will be fine, if you include the 1:2 clutch reduction.

On the photos you can see my throttle setup hooked up to the pedal.

I've also attached my exhaust. Not sure about the place of it now. I would love to move it more upwards.

Is there anything you think is wrong? Or do you have any question? Whatever, I'm open to anything!

 

[mysteryboy28]

so your final gear ratio will be?

 

[r97]

so your final gear ratio will be?

(axle sprckt teeth/engine sprckt teeth)clutch reduction=crankshaft rotations:axle rotations
(45/12)2=7.5:1

Nodroz,

The kart looks pretty good so far. Do you have a throttle return on your engine as well as the one on the pedal? Are you brakes fully functional? Do you have an easily accessible kill switch installed? Do all bolts have some kind of locking device on them? You gear ratio sounds good to me, with 18" tires your theoretical top speed is about 26mph, or about 42kmh at 3600rpm. FYI, your wet clutch/reduction case has a ratio of 2:1, not 1:2.

 

[Nodroz]

so your final gear ratio will be?

According to r97, 7.5:1, which is quite good in my opinion.

(axle sprckt teeth/engine sprckt teeth)clutch reduction=crankshaft rotations:axle rotations
(45/12)2=7.5:1
r.

Nodroz,

The kart looks pretty good so far. Do you have a throttle return on your engine as well as the one on the pedal? Are you brakes fully functional? Do you have an easily accessible kill switch installed? Do all bolts have some kind of locking device on them? You gear ratio sounds good to me, go out and measure your tires so you can throw your numbers into a speed calculator.

Yes, I have a throttle return spring on my engine aswell. If the cable ever gets loose or brakes, then the throttle will always be set to idle.

Brakes, that's another story. I'm having trouble with a bolt on my brake. The whole bolt head got ruined. I couldn't get it loose again. The brake disc with the hub has been braught to a dude who will fix this for me.

No kill switch installed yet. I have the switch laying here, just need to get it attached to the frame!

About the bolts, no. I'm going to the shop Wednesday to get bolts with a nylon nut so it won't get loose.

I have 18" tires. According to the speed calculator I'll be able to go 29MPH @4000rpm(or 46KPH for the Europeans here). That's perfect for me. You don't want to much faster in this.

The governor has been removed from my engine and I'm unsure about any other mods that has been done to this engine. The 4000 rpm I used in the calculator is a guess. I'll probably go faster...