Engine doesn't move the kart.:(

[Angel]

Hey guys, 2 days ago i finished building my go kart but now i'm kinda upset. When i pull the throttle the engine's axle is rotating faster but it doesn't move the whole assembly and the clutch smells burnt. That's a pic of my transmission :

Any advice?

 

[jonboy]

Belt looks like it may be a little too tight.

 

[mckutzy]

I'm going to guess, you are going to need a bigger axle pulley, I'm going to assume the 6:1 ratio still aplies to pulley.

 

[Doc Sprocket]

Yup. Way overgeared. You need a MUCH larger axle pulley (that's NOT welded on there, is it?!?!)

 

[landuse]

Yup. Bigger axle pulley needed. It looks like that one is welded on, which might be a problem getting it off

 

[Angel]

it is welded but i can get it off. So you think the size of the pulley might be the problem?

 

[mckutzy]

Oh ya.
Don't weld it to the shaft, need to get a keyed shaft and appropriate pulleys.

 

[Angel]

so i should use a six times bigger axle pulley than the engine' as mckutzy said?

 

[landuse]

so i should use a six times bigger axle pulley than the engine' as mckutzy said?

Yes, that is correct. With pulleys, you can use the pulley diameter. Sprockets we use tooth count

 

[anderkart]

so i should use a six times bigger axle pulley than the engine' as mckutzy said?

Maybe, but that size might be larger than your back tires...

We could give you better advice If you measure and post, what size your engine (clutch) pulley is, and also tell us how tall your back tires are?

 

[Angel]

clutch pulley has a diameter of 7cm, axle pulley has 11 cm and back tires have a diameter of 25cm. But would a variator help?

 

[anderkart]

clutch pulley has a diameter of 7cm, axle pulley has 11 cm and back tires have a diameter of 25cm. But would a variator help?

Wow, Your 7cm clutch pulley is 2-3/4" diameter, that's equivalent to using a 21 tooth (#35 pitch) clutch sprocket...

Your 11cm axle pulley is 4-21/64" That's the equivalent of a 34-tooth axle sprocket, and that calculates out to your current gear ratio being a 1.6:1.

Your 25cm rear tires = around 10".

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You'll need to install a jackshaft (like the 4 pulleys in this picture) if you want to use your belt clutch.
Is that what you call a Variator?

If you install a jackshaft on your kart:
You could use your 7cm pulley clutch, with its belt running to a 22cm (9") jackshaft input-pulley.
And then you could install a 6cm (2-1/2") jackshaft output-pulley, with the second belt running to the 11cm axle pulley you already have on your kart now. That would give you around a 6:1 ratio that should work good on your kart

 

[Angel]

that's what i'm gonna do, but wouldn't it affect the speed?

 

[firemanjim]

Yes, slows your top speed down to something realistic.....but you will have great take off!

 

[anderkart]

that's what i'm gonna do, but wouldn't it affect the speed?

What engine do you have? If you post its cc/size, horsepower and max rpm specifications, we could estimate your karts top speed.

 

[Angel]

I absolutely don't know, i guess it's about 60-70cc but i don't know anything more

 

[Angel]

Yes, slows your top speed down to something realistic.....but you will have great take off!

what do you mean by realistic?

 

[firemanjim]

Realistic as in the 35-50 mph.....

 

[OzFab]

Post some pics of your engine, we may be able to figure it out...

 

[Angel]

Pics of engine

Here are some pics of my engine


The serial is ENB 390754 R D