gear ratio

[chadm3us]

i am new to go karts, more of a fun kart big tires on back and small on front.I am having trouble with the gear ratio.i am running a jackshaft just because that is the way it was set up. i have 72 teeth on the motor and the wheel and a 12 tooth clutch i have tried a 36 tooth gear and it has no torque if i use a 16 tooth i cant start the motor because it wants to pull the wheel.any help is much appreciated. i could also provide pictures if someone could tell me how?

 

[2or3wheels]

Pics would work great? You hav e a 72 on the motor?

 

[chadm3us]

i have the pics on the computer but i dont know how to get them here and i work nights so im only on here in the morning

 

[2or3wheels]

If you have 72 on the motor i can see how that may give you way to much speed.

 

[chadm3us]

is that why i have no torque and i have the pics but dont know how to put them on here if i jack up the back end and start it the wheel goes pretty fast with no weight as soon as i sit on it it goes nowhere.

 

[2or3wheels]

Isnt there a clutch on the engine?

 

[chadm3us]

yes i have a 72 tooth gear on motor to a ? gear on the jackshaft to the 13 tooth clutch to a 72 tooth gear on the wheel.

 

[2or3wheels]

need to figure out the ? gear and how tall the drive tire is.

 

[chadm3us]

i can measure the tires but that is why i started this thread was to figure out the ? gear that is where i put the 36 tooth and have no torque and if i put the 16 tooth on there i have too much and cant start the motor

 

[mikeandike]

ok, take off the 72 tooth gear on the motor. Then put 2 equal gears on. One on the jackshaft where ? is and the other on the motor.

 

[chadm3us]

what will that tell me?

 

[2or3wheels]

put a much smaller gear on the motor plain and simple, i dont see how a 72 tooth sproket can fit on a motor without it being lower than the block, please pics would make this much much easier.

 

[chadm3us]

i have measured the wheel at 19 inches including the tread im still trying to post the pics but the ones from my camera are to big i think and now i have some on my phone but still trying to post them.

 

[chadm3us]

 

[chadm3us]

hey it works

 

[pete]

Do what 2or3Wheels said. Change the sprocket on the motor to the same size sprocket on the jackshaft.

 

[chadm3us]

wont it have too much torque and no top end

 

[chadm3us]

and where would be a good place to get one its a one inch shaft and i have a 36 or 14 tooth sprockets to go on the ? spot

 

[pete]

If I understand correctly you are trying to run a 72 on the motor, 13 on the jack shaft, 13 on the jack shaft and 72 on the wheel. That's a 1:1 ratio. That will never work. You need about a 6 to 7:1 ratio.

 

[2or3wheels]

Do you have a clutch somewhere? It would be great knowing the ? gear.