Ideal rear sprocket size? 44? 36?...

[Nehmo]

Assuming
a 49cc 4-stroke engine
26" wheels
Mostly flat terrain
Not a racer, just practical getting around

What's the best size for the rear sprocket? Most kits come with a 44 tooth one, but most CNC ones that mount by clamping the hub are 36t, it seems.
I don't like the rag connection, and I want to replace it with one of the more accurate clamp-on-hub type. But I need to decide on the tooth number before I order.

 

[Greg58]

I run a 44 with my 48cc 2-stroke, I have tried a 41 and didn't like it. Unless you are willing to do a good bit of peddling I'd go with the 44.

 

[Nashville Kat]

I have a 39 on my 48cc build- Been wanting to change it to 36, just don't have the time. You get better speed and less vibrations, and it handles flat terrain fine. Plus, it's easier to eliminate the chain tensioner then, the chain has more frame clearance the smaller the sprocket

 

[MotorBicycleRacing]

I run a 44 with my 48cc 2-stroke, I have tried a 41 and didn't like it. Unless you are willing to do a good bit of peddling I'd go with the 44.

4-stroke engine

 

[Nehmo]

You are Assuming that we know what transmission you have on your Hausheng.
...

The engine I have didn't come with much documentation, and I don't know what kind of transmission I have. How do you tell?

 

[MotorBicycleRacing]

You are Assuming that we know what transmission you have on your Hausheng.
Can't give you an answer without knowing that ratio.
Ignore the advice for 2 stroke motors above.
You probably need to go bigger than 44 but definitely no smaller.

Assuming
a 49cc 4-stroke engine
26" wheels
Mostly flat terrain
Not a racer, just practical getting around

What's the best size for the rear sprocket? Most kits come with a 44 tooth one, but most CNC ones that mount by clamping the hub are 36t, it seems.
I don't like the rag connection, and I want to replace it with one of the more accurate clamp-on-hub type. But I need to decide on the tooth number before I order.

 

[Greg58]

From the picture you probably have rode it so how good does it work now? If you need more top speed go smaller, more low end go bigger. A persons size makes a difference also.

 

[Nehmo]

Actually,

From the picture you probably have rode it so how good does it work now? If you need more top speed go smaller, more low end go bigger. A persons size makes a difference also.

I haven't even put the oil in this one yet. I just finished putting it together, and I still need some finishing touches, like a gas cap.
I was looking for opinions from people who already had experience with a similar setup.
BTW, what kind of gas cap works? It's a 3cm hole with a 4.5cm OD for the filler tube.