ORIGINAL: Jezmo
The 26 has the the regulator side of the carb facing the wind blast which is higher in flight than on the ground. The reference hole in the little cover needs to have a tube soldered in, a short piece of tygon put on and inserted into the fuse where the pressures SHOULD remain constant. The way it is stock, as the airspeed picks up the reference hole picks up increased pressure which presses down on the diaphragm holding the needle open more than normal resulting in a rich mixture when you throttle back. It may take a little experimenting to find a spot where the pressures remain constant and don't influence the carb mixture. You can search for pics of the mod here on RCU, that's how I found out how to do mine and it really helped. Good luck.
I concur 100%!
If you want, you can run the tube out the bottom of the cowl, and bevel the bottom of the tubing at a 45 degree angle so that the bevel is facing backward. THe factory velocity stack is also an important part to install. It will eliminate alot of the turbulence in the air entering the carb, which wil alow more constant mixtures.