CVT transmission ratio for Honda GX-35

[Otto Neumann]

Hi,
I'm a new user,and I've started my plans for my first gasbike,with the additional personal challenge of running the entire project on a very low budget,and until now it's proceeding greatly,but I stepped into a problem
that I can't solve alone.

I'm using a GX-35 engine,and I can't find a proper transmittion mechanism to fit on it.
Recently I've spotted on ebay some 3:1 chain driven transmissions and some 5:1 gearboxes destined for minibikes,but I don't know which ratio I should choose.
Actually I've seen a bit of people around using the 5:1 gearbox with this little mechanic wonder,but it's still not enough to convince me;

Do you have any suggestions?

Thanks for your time
-Otto

 

[machanic]

How are you connecting the engine to the wheel friction, direct chain or shifter, the 2 stroke china motors have 4/1 at the engine clutch, a ten tooth on the output to about 40/50 teeth at the rear wheel.

 

[Otto Neumann]

I'm connecting the engine with a direct chain,I've seen those,but a 4 stroke it's more convenient for me,in therms of fuel consuption.

 

[curtisfox]

3:1 or 5:1, you still have to reduce the ratio after the transmission. You need a total of about 10:1 or 12:1

It is figured with teeth count like 10 front tooth divided into 40 tooth rear = 4:1. Belt is figured by size 2" into 6" = 3:1

It can also be done with jack shaft, with a series of belts or chains. That's about all the trans does, aside from the clutch bell or drum. It is a jack shaft in a case.

I do believe the one of them trans changes the rotation direction, double check...................Curt

 

[Otto Neumann]

Thanks
Originally I calculated that my optimal set of sprocket would be a 12T / 44T sprocket

 

[curtisfox]

Here is a chart that will give you speed also, but all depends on load and hills also.

http://jimsitton.net/ratiocalc/

 

[Otto Neumann]

Here it's mostly flat,plus I'm intended to use the engine for sustain speed and cruising,I don't mind to have a quick thing and pedal a bit more ^^

Omg 57 mph with a 12T / 44T at 2700 RPM with a 26 inch wheel?
Good,the gear ratio is at 3,67 : 1,it matches my calculations

 

[curtisfox]

Now all you have to worry about is if the motor has enough power to pull it, may have to go lower................Curt

Staton-inc has a lot of parts for them motors. http://www.staton-inc.com/store/

 

[Otto Neumann]

I've seen quite a bit of bikes running with a Gx-35,but they used a bigger sprocket,a 47T one,I choose a slightly smaller sprocket for get a 20% of extra speed,as I will bring the bike to the optimal speed for after engage the engine,I really don't mind to accellerate by pedaling a bit.
Of I don't have enough torque I can still improve it by changing the driving sprocket:
Like,by using a 3:1 transmission with the stock 11T sprocket I can gain a 8% of torque,and if I change it with a 14T I can gain even a 16% of Torque

 

[curtisfox]

Sounds good, good luck with your biuld..............Curt