Hi Udo - many thanks for response. You are right - my headers were designed in CAD and then mandrel-computer bent. The issue on the M8 is that the header bends don’t have enough straight length between them which is required for the grip length of the machine. Therefore I have to make the headers in a conventional way out of separate bits and pieces. Seeing your effort to get them to that perfect level scares me quite a bit …..Hi Wolfgang, Sorry to take so long to reply, I Haven't had a chance. I did my headers very old school. Firstly I got a chart off the net specifying the ultimate sizes and lengths for Primary and Secondary pipes for that size engine and rev range. ( See the attachment. ) Then I ordered a selection of bends, donuts, and pipe and a pair of header plates. Then I made up a couple of jigs to cut the bends square to the center of the radius, and bought a heap of hacksaw blades. You are right, I used a wire model and made the ones furthest away first ( nos 1 & 2 ), then proceeded to the next, doubling back to obtain the same length to the collectors. Making sure I had access to the manifold bolts, spark plugs and still get the rocker covers off.
I notice all of yours are one piece and beautifully bent up in I presume a computer programmed bending machine of some sort. You're not thinking of making them differently are you ?