110cc Single Tao Motor with 3 speed trans. What axle-sprocket tooth count should I run?

[Jacka$$withawrench]

More of an opinion post, I want to hear what number of teeth yall have on your karts. Engine was originally from an ATV, with the 3 speeds being 0.65:1, 0.85:1,and 1:1 as best I can tell. PTO shaft sprocket is a 16 tooth, what number of teeth should I run on the rear axle? It is the same live axle arcade racing kart as before.

 

[panchothedog]

Tire diameter will have a lot to do with it. If the tire size on whatever you are putting this into is the same, or close to the ATV it came off of, then you should use the same size axle sprocket the ATV had. If tires are a lot smaller, then you can use a smaller axle sprocket. Figure out the circumference of the two different sizes and calculate accordingly.

 

[Whitetrashrocker]

I used a taotao 250 engine 4 speed. Came with a 15/39. I got a 16t and 17t with a 40t on the axle. 18" tires. I like the 17t best.

 

[Jacka$$withawrench]

Tire diameter will have a lot to do with it. If the tire size on whatever you are putting this into is the same, or close to the ATV it came off of, then you should use the same size axle sprocket the ATV had. If tires are a lot smaller, then you can use a smaller axle sprocket. Figure out the circumference of the two different sizes and calculate accordingly.

Original were 18" tires, now they are 6" OD slicks, so I think I'll go with a 30 tooth. Any ideas on where best to get it? I mainly use Mcmaster-Carr for hardware.

 

[bob58o]

with the 3 speeds being 0.65:1, 0.85:1,and 1:1 as best I can tell. PTO shaft sprocket is a 16 tooth, what number of teeth should I run on the rear axle?

Best you can tell might not be good enough.
I assumed these engines might be geared liked something below.

Primary? 3:1?
1st 3:1 ( 9:1 total)
2nd 2:1 ( 6:1 total)
3rd 1:1 ( 3:1 total)

if you are inverted, 0.65 is about 1.54 :1
0.85 is 1.18 :1

I have no clue what your primary reduction is and those gear ratios seem suspect to me. If you can find out what the true sprocket counts are in the gear box I could provide better suggestions.

going from 18” diameter tires to 6” diameter tires reduces circumference to 0.333 of the original size. To keep ratio consistent, you would need to decrease the rear sprocket tooth count (from the original vehicle) to have 1/3 of the teeth. For example: 16: 48 with 18” tires is the same as 16: 16 with 6” tires.

Depending on weight and desired speed and or need for torks, you probably want to adjust.

Little slick tires and too large of a sprocket might have you doing burnouts and or wheelies.

 

[bob58o]

With 6” tires, the axle needs to turn 1680 RPM to go 30 MPH. If you want 30 mph in 3rd gear at 6000 rpm, then you want overall reduction in the range of 3.5 :1 in third gear. If primary is 3:1 and 3rd is 1:1, with 16T on output shaft something like 19T on the axle would give 30mph at 6k

Somebody correct me if this seems off.

If everything else stays the same in the previous estimate but we swap to a 30T instead of 19T we’d be doing about 14mph at 6k rpm in 3rd gear.

 

[bob58o]

BTW, what are these 6” diameter slick tires and what wheels are they on? 6” tires or 6” wheels?

 

[panchothedog]

I could be wrong, but I think most all go kart tires ( not wheels ) are a lot taller than 6". That's almost toy sized.

 

[bob58o]

I could be wrong, but I think most all go kart tires ( not wheels ) are a lot taller than 6". That's almost toy sized.

I was wondering if this was the project where they insisted that hand truck wheels were good enough, but the “slicks” made me think they were indeed gokart tires. Maybe the wheels are 6”? I think 6” wheels are normal for karts. Maybe 10-12” tires are “normal”? Even a 4” rim and tire with 2” sidewall would be 8” tire diameter.

 

[bob58o]

Not gokart wheels nor tires.

 

[Jacka$$withawrench]

I was wondering if this was the project where they insisted that hand truck wheels were good enough, but the “slicks” made me think they were indeed gokart tires. Maybe the wheels are 6”? I think 6” wheels are normal for karts. Maybe 10-12” tires are “normal”? Even a 4” rim and tire with 2” sidewall would be 8” tire diameter.

they are 6" Go kart racing slicks, 3 bolt pattern. I posted photos to the thread "How to transfer power sideways 3 inches?"

 

[bob58o]

they are 6" Go kart racing slicks, 3 bolt pattern. I posted photos to the thread "How to transfer power sideways 3 inches?"

Oh ok, I’ll take a look. But as mentioned before, I only got the two. Lol

Just to be sure, did you measure the 6” height of the tire? Or does the tire say something like “x6” indicating “RIM” or “WHEEL” size. Even 4” rims with 4.10-3.5 x 4 tires are taller than 10”.

 

[bob58o]

I guess I don’t believe the tires are 6” diameter. The tire looks as tall as it is wide and it is as wide as the engine.

In the words of Morpheus….

 

[panchothedog]

So Jacka$$. Instead of sending us on some kind of search to another unrelated thread, why don't you just get out a tape measure or a yardstick and tell everyone thats trying to help answer your question, what is the diameter of your tires. How tall are the round rubber things your kart rolls on.

 

[Jacka$$withawrench]

So Jacka$$. Instead of sending us on some kind of search to another unrelated thread, why don't you just get out a tape measure or a yardstick and tell everyone thats trying to help answer your question, what is the diameter of your tires. How tall are the round rubber things your kart rolls on.

Measured, wheel in total is 8 inches in diameter. I apologise, I don't know where I pulled 6 inches from (certainly wasn't out of my pants). I mounted the engine with a temporary gas tank (cup+tape) and used a 48 tooth pitbike sprocket and that seemed to work fine.

Next up: Can yall please advise me as to how do I find/make a cheap gas tank?

 

[Whitetrashrocker]

Old fire extinguisher bottle.

 

[panchothedog]

Sounds like a workable idea. Do you have the ability to drill and tap it for the appropriate fittings, as well as a port for filling and a vented cap to seal it.

 

[Jacka$$withawrench]

Sounds like a workable idea. Do you have the ability to drill and tap it for the appropriate fittings, as well as a port for filling and a vented cap to seal it.

I have a drill press and taps. Just drill a hole in the bottom and tap/screw a barbed nub in, then replace the original spray head with a vented cap?

 

[Whitetrashrocker]

You can steal my idea. I used an oxygen bottle. Welded on a neck and cap from a power steering box.

Post in thread 'A tale of two Dingo's' https://www.diygokarts.com/community/threads/a-tale-of-two-dingos.34201/post-433540

 

[Jacka$$withawrench]

You can steal my idea. I used an oxygen bottle. Welded on a neck and cap from a power steering box.

Post in thread 'A tale of two Dingo's' https://www.diygokarts.com/community/threads/a-tale-of-two-dingos.34201/post-433540

Two Questions:
1) Is the right angle turn in the bung important? Or can I just flow the fuel straight down?
2) How did you find the bearings for so cheap? I'm looking at replacing one of mine (it stuck, but works with heat and WD-40) but cheapest I could find was this: SKF - 1-3/16" ID x 2.4409" OD, 3,380 Lb Dynamic Capacity, Insert Bearing Insert Bearing | MSC Industrial Supply Co. (mscdirect.com)