Help with gear ratio on CG125 kart

[3gd16]

Hi guys i am new here but not new to the go kart scene i have a one seater kasea go kart witch i have modified a bit to fit my liking. I moved the rear tire 5.5 inches back to make it long so the engine would fit properly and modified the strut mounts and mounted a cg125 5 speed engine. The problem i am having is the gearig the engine revs and works fine it is being rebuild and modified right now, there is a 12 tooth sprocket on the engine and a 31 tooth sprocket on the axle (2.5:1 ratio). The engine has an overbore kit from 56.5mm piston to a 62mm piston putting it at 150cc, has a mild custom cam, ported head, 27mm carb. My question is how do i figure out the ratio with it being a 5 speed engine? I don't need speed i want low end torque

 

[KartFab]

My question is how do i figure out the ratio with it being a 5 speed engine? I don't need speed i want low end torque

I am pretty sure you are going to get ridiculous amounts of both speed and torque with your 5 speed engine.

 

[3gd16]

I am pretty sure you are going to get ridiculous amounts of both speed and torque with your 5 speed engine.

It feels as if it needs more torque down low in the rpm

 

[Joe-405]

If you want more down low torque then go bigger on the axle sprocket. I'm guessing about +5 should do the trick for what your wanting to accomplish. Just remember you will lose your top speed some.

 

[3gd16]

Thanks i will look into a bigger rear sprocket, i am not to worried about top speed cause its a trail buggy more then it will be a street buggy

 

[firemanjim]

Try a 50 tooth.... You will have stump pulling low end torque......

 

[OzFab]

On a side note, one thing to consider is, as a result of moving the axle back, the steering will suffer...

 

[3gd16]

On a side note, one thing to consider is, as a result of moving the axle back, the steering will suffer...

It steers really good actually

 

[firemanjim]

Flip your back tires around..... They are backwards.......

 

[landuse]

Flip your back tires around..... They are backwards.......

Yup.