I'd be more than a little shocked if you can buy a 'rebuild kit' for your engine. What you really need to do is open it up and find out what's going on. You may find something that can be relatively easily repaired and can assemble a short list of the needed parts. On the other hand, you may discover catastrophic internal trauma. Diagnose the specific problem first, then determine the strategy to resolve it. Don't dismiss the option of buying a used motor as well.
It would be a great idea to add your bike info to your signature.
It would be a great idea to add your bike info to your signature.