Hi Flywilly. Interesting about the glow plug, I had forgotten about that. Seems to be very little about the DLE35RA on a pipe when it seems such an obvious thing to do. I managed to deduce the exhaust timing from the available info, stroke 30mm and rear view drawing. As i expected it was a conservative 148 degree duration, about right for a muffler. For a pipe 164 degrees would be better. This means grinding 2mm off the top of the exhaust port. For tuned pipe design Jennings two stroke tuners manual is the holy grail.
https://www.google.co.nz/url?sa=t&rc...gg3gqCxILowdeH
I design pipes for broad range though so the front cone is set for a lower rpm than the rear one. I make my pipes from .6mm ali sheet brazed together with a propane torch. However commercial ones will work fine. Header size looks like it should be 7/8".