I've heard you loose up to 5% power through a 150cc engine using flex headers over solid headers. The flex headers are alot easier to use than the solid headers, especially in a Carden where everything has to be perfect to line up. I cannot fathum 5% power being lost just from 5" of flex tubing. Shed some light on this myth please. I would think that since the bend is solid that it shouldn't loose power for the straight part of the header being flex tubing.

-Kelly

P.S. Here is a picuture of my header for referance.