Been doing some more mucking around with the new 70cc/Dellorto setup. I originally started with a very rich 98 main jet, and stuck with the 50 idle jet which came fitted to the Dellorto. I was actually having a lot of trouble to get the idle to crack cleanly in the 1-8-1/4 throttle range, so downsized to a 45 idle jet which seems a bit better. I realised after ringing the throttle harder, that the 1/4 throttle cleaned up a lot more, so i don't think it was a case of the original 50 idle being bad, so much as the plug was just fouling up at low rpm's.
Anyhow, first run on the 98 main jet was waaay too rich. I could barely get past 7,000rpm without it 4 stroking quite heavily. I then dropped right back to a 92 main, and went for a ride today. It rides much nicer, though it still hesitates in the upper rpm's unless you wind up the throttle very gradually. Essentially, it is still too rich but i'm getting results. Even with the 4 stroking in the upper rpm's, it's picked up a few more mph, up to 55.8kmh / 34.6mph. The temperature is slightly concerning, so I will be looking to use the Puch gigantor head, which can only make things better. In the mean time, i'll drop to a 90 main and do a plug chop.