I picked up a Sportster .20 NIB and I must say, when I first turned it over it gave me a moment of doubt. There was very little compression and it turned like it was filled with molasses.

Out on the test stand with 22% oil half castor and 10% nitro, I used the electric starter because it was so sluggish. Short runs rich, with leaning out briefly before shutting down and cooling. A few cycles, and what do you know?...it's got compression and isn't so sluggish! It just got better and better, and soon it was an easy hand starter. Holds compression beautifully at TDC. First time I felt a sense of accomplishment from an engine break-in.

After beginning with a 9x4, I moved up to a 10x4. Eventually I tried an 11x4 and that went fine, so tried one short run with a 12x4. It hummed along happy as a clam. I love this engine now. Just picked up a .28 NIB too.

Stock carb works fine by the way

Jim