here's the problem, I was riding today every thing going fine. I stop to get gas and when I try to start my bike the starter engages and the open primary just spins im lost any ideas. It is a custom bobber with Ultima 113 motor Ultima 6 speed Trans and Ultima open primary. Thanks for any help.

 

Basics first, is there fuel getting to the carb? Is there spark getting to the plugs?

 

yes its getting fuel, its like the engine is just free spinning

 

Your explanation is unclear.

Exactly what happens when you push the start button.

Is the starter motor spinning?

Is the engine turning over when the button is pushed?

 

Yes the starter is engaging and spining the entire primary, but the crankshaft just spins, the motor not even trying to start

 

Sounds like something broke on the engine side of the primary belt. Is there something like a compensator there?

 

Sounds like no compression. You need spark, fuel, air, and compression. Not trying to insult your intelligence. Pull the plugs and coil wires and put your finger over each hole and crank. It shoud pop your finger off and both cyl should sound the same. Do you have gear drive or chain?

 

well it looks like the teeth on the sprocket offset collar that go over the crankshaft are stripped. I dont know how that could happen. thanks to everyone for the help.