Re: Please Help
Welcome to the forum. We're glad you've joined us. Please keep in mind that this is a family forum so we ask that you keep the content of your posts in that context.
You'll find plenty of help and good advice here to assist you in getting your motorized bicycle up and running.
As said above, running without a muffler is not a good idea for several reasons. Primarily if the entire exhaust system is what is "falling off" you need to address that because of potential damage to the engine. If it is just the end cap on the muffler that is coming off there are remedies for that such as drilling a small hole and threading in a screw.
Another reason for keeping the muffler on is the negative attention your bike will draw without it. Our hobby has some legal issues that we try to keep away from and running a bike without a muffler is one of them. Please don't ride the bike unmuffled for your sake as well as the hobby in general.
When you say the bike "sputters" when going slow, how slow is "slow"? If your speed drops below 10 mph you should disengage the clutch and pedal. The engine will sputter, run rough and jerky below about 10mph with the clutch engaged. Not quite sure what you mean by "The clutch makes me uncomfortable". Can you explain? The clutch is a critical part of the motorized bicycle and should be used as it was designed.
Hope we've helped a little and we're always here to offer advice.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"