So I drilled my Bing on my Puch Maxi Luxe 1.5hp from 12mm to 14.5 mm. No real top end improvement to speak of(maybe 2-3 mph faster), but the low end is killer now. I am doing 25 mph up pretty steep hills.
With the 72 jet it would not get over 25 mph flat ground while four stroking the whole way. Put the 70 in and it is like 100% better with a 33-34 mph top end (plug chop said I was running lean, so I taped up the air filter and not it is just right and I have the same top spead. With the pipe and the air filter it was a huge difference in the 72 to the 70 jet...then I had to still tape up the filter to get it richer.
anyone got any opinions?