Modern Vespa

i did not know if there are any ticks to installing prima pipes on my s.
the strap broke about a week ago and i had my work make me a new thicker one. it works well but now the motor sounds different. not by a lot but that is does not backfire anymore. (it is not loud anyway but it would make some noise when you back off the throttle) could this be a leak in the seal up where the motor is? visually it looks alright, but idk when it gets up by the motor if something is not fitting right and that is the problem. thanks for your help.

Good luck.

Prima exhaust keeps breaking on Vespa S150

thanks but i amn looking to know how to tell if there is a leak in the system. i turned the scoot and felt around and felt some air moving but it could be just from the cooling fan. but i made an exsact copy of the strap at work but it is about 2x as thick. works great, little different noise though, i also called my dealer and if you write the company they will send your dealer a new thicker strap for free. i guess they have fixed this problem. but like i said i am looking for the secret to telling if your pipe is leaking somewhere?.