just to resurect an old topic...

due to a misfire from a leaky coil i blew my (old faithfull)crossbox wide open today on the way home,spare coil on and continued up the hill home

couldnt get the engine to rev past 4000rpm under load wheras untill the box blew it will easily pull to 6250. low end seemed un affected but i had to feather the throttle in 4th thru the village.....well gave it a blip at a certain house to try kick off the bmw alarm

so the box does more than just muffle the noise, but then i knew that.
To gain extra from an open pipe the carb will have to be re jetted...but i knew that
What did surprise me was that it was top end that was affected as theoreticaly an open pipe should let the engine rev more, the way my set up runs the engine is a rev happy one that sits at an indicated 70-75 all day with no problems

oh well will have to unpack some boxes to find a crossbox....i hate doing cross boxes

Sean