I just got back from a test ride, where I attempted to vibrate the seat mount up my arse. It revs up much quicker, and I estimate has about 1/3 more power than it did before the intake modifications. One thing that I am tickled with, (besides vibrating seat mount) is the ease of carburetor adjustment, and how predictable the throttle and acceleration is.
I'm very happy. The ratio I will stick with is a final 1:5.5. It wants a bit lower than that, but carries the power okay. (Tires are 12" diameter) It will idle all day if I let it. No loading. Tilly clone is fuel pump down, and cover snug, but it will drip fuel until I shut off the tank. I can deal with that.
I wouldn't expect a lot more from this tiny engine on gas. (Using Burris at 20:1) Time for celebratory adult beverages, while sucking down cigarettes and blue castor oil smoke.