4 stroke Duel Chain transmission issue

[BellStar]

I recently bought this Chinese 100 cc, 4 stroke bicycle motor for getting back and forth to work. The engine is running great but the duel chain transmission is not work and has not since first firing the engine. The first chain spins smoothly but the sprocket that connects to the wheel has zero power. I can smoothly pedal it but when revving the motor there's no additional power. Obviously the second chain was attached at the time of testing.
I really need this motor to work and will appreciate any help that I can get.

Thanks,
Joe Bell

 

[Chainlube]

This is the end of the crank, a piece of steel fits in that slot.

 

[DAMIEN1307]

This part should have a small square piece of steel that fits in a groove on the engine crank shaft. It's call a key.

There is probably a key on the output sprocket on the other side as well.

Here is the basic description to what is being introduced to you as a "key".

https://www.huyett.com/blog/woodruff-keys

 

[BellStar]

There should be one going to the rear wheel. However, from the description dual chain he's saying the input side of the jackshaft is spinning but the output side isn't moving. Which suggest a backwards freewheel or a missing key.

 

[BellStar]

Here is the basic description to what is being introduced to you as a "key".

https://www.huyett.com/blog/woodruff-keys

Is it typical that a key would be missing from a new product? Can I purchase, with some certainty that it'll fit, a replacement key?

 

[Sidewinder Jerry]

Is it typical that a key would be missing from a new product? Can I purchase, with some certainty that it'll fit, a replacement key?

Was everything already assembled? Did the engine come with the transmission attached to it?

 

[michael whiteman]

Even the sprockets have keyways that align with the keyway in the shaft. These keys are rectangular, 3/16" square and about 1/2" long. All these keys can be found at ACE Hardware. When it's all fixed and you have the back wheel jacked up off the floor it will turn when you turn the drum (the outside) of your clutch by hand. You'll find the problem, I'm sure. BTW welcome to the forum.

 

[BellStar]

Thank you very much! I did not expect this much help and I appreciate it.
I'm going to make a run at it today and this has definitely given me things to work with

 

[Chainlube]

Thank you very much! I did not expect this much help and I appreciate it.
I'm going to make a run at it today and this has definitely given me things to work with

Best test to see if the key is missing from the assembly is to hold the big gear of the trans and pull the rope. If the rope moves the gear well, then the key is there. If when you pull the rope and the gear stays relatively put, may turn a bit from friction, then the key is missing or broken.