so after two days of trying to start my motor ( 80cc) it finally started. the way i got it to start was by taking the muffler off. it started first try after this. i put the muffler back on and it wouldnt start. i then took off the end cap and now it starts and runs good. my question is, will leaving this end cap off ruin my engine? also, are there any aftermarket mufflers out there? thanks, brian.