Re: WOW ! I thought I was on my own...
The trick to tuning is NOT to open out the inlet, it's too big as it is. Using standard Honda bits, just find the piston with the greatest deck height and compression. Leave the cam, get a carb that breathes enough juice (they like being slightly rich). Shortish header, about 22" from the valve head itself. There's no top end go, but it will shove off the line at a thoroughly silly rate of knots.