MoMo, the pipes are 4 into 4 customs made by a bloke here in Australia - I got them through the local CB750 Owners Club. They sound a bit like the originals with the baffles out, and really good at idle without sounding over the top when revs are up. Hoping for some 'on the road shots' soon! They're an amazing old bike. There's a bloke works where I live who's been riding a 750/4 to work every day for years - he's got the motor in a Santee frame - the frames where you put a swing arm in for some rear suspension. Met him on the road again today and she looked and sounded just like she would have back in '73. I've got the same frame and not sure whether I will one day try and build a low rider chop using my motor. Getting it registered here is a problem. Slug