Funny you post this now . I'm going through this at the moment . The pic was just a dry fit on the bike ( w/o reducer ) . I purchased a Supertrapp that needed a reducer that i had made in stainless from a co. in the UK . The motor is a total fresh rebuild ( primary chain-new cam ect...) . Motor starts up perfect , carbs synced ect... I did have some reversion and some white smoke that always seemed to be there and some popping .. I did the build in my basement and figured the condensation+ rebuild lubes ect.. would burn off . I removed the Supertrapp and everything was perfect , no smoke or popping . I used a set of Supertrapps on a 85 Maserati BiTurbo i built years ago ( i bent and welded my own exhaust ) so i figured i can adjust my back pressure with those mufflers by adding or subtracting discs. It took a weekend to dial it in but it worked great . I think the reduction in diameter would be a problem and some power band would suffer but w/o getting the bike on the road and experimenting i cannot be sure . I was confident i could dial it in ( probably adding a few more discs ) I know this is a ( long ) non answer but it is a good question . I was even thinking of flush cutting the Supertrapp and TIG welding it to the pipe or sleeving it to that diameter . The ST's do sound nice though. My BiTurbo sounded like a f-16 idling through the neighborhood.
