theyalwaysland- YES! The YS-45 on a pipe not a stock muffler is about the closest thing to a Jett for sport engines... A Macs full-pipe 7.5CC and look out-

I have flown a WHip with the YS-45, a Patriot, and a Lanier F-4 all with the YS-45, OS-F plug and Powermaster 20/20% fuel

I bet your engine will run up just fine... make sure you still have the check (one-way) valve and the plumbing correct---- Keep us posted!

P.S. I have a YS-60 I got from Petec on here and I will not EVER part with it- YS-45's are always on Ebay though