Check to make sure you didn't accidentally plug up the exhaust port, or pull a wire lose. I don't think it can be anything else, IF it was running well before you did anything. How long has it been sitting? old gas can gum up carbs and or injectors. IF it was running and replacing the muffler made it not run, all it can be is a plugged exhaust, or a wire erroneously pulled loose.
Answers & Comments
Check to make sure you didn't accidentally plug up the exhaust port, or pull a wire lose. I don't think it can be anything else, IF it was running well before you did anything. How long has it been sitting? old gas can gum up carbs and or injectors. IF it was running and replacing the muffler made it not run, all it can be is a plugged exhaust, or a wire erroneously pulled loose.